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Gear suggestions

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69stang_250
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Gear suggestions

Post #1 by 69stang_250 » Sat Dec 24, 2016 11:31 am

So I have my car going and have gotten to do some driving on the interstate and around town and here is what I see.
Mind you I have a 4cyl t5 with a fresh rebuild, steel cluster shaft retainer, and an aftermarket shifter to keep from over shifting. Out back is 3.00 open rearend.

Driving around town: first-fourth is the only gears you can really use un to 55. I honestly put it in 5th once and it dropped the rpms to 2100. Not bad for cruising, but you have to down shift to 3rd to get any speed up. The engine starts to pull at 2400-2600.

Driving on the interstate: at 80 the rpms are around 2500. I don't mind that much as my truck runs a little lower rpms than that on the interstate, but you stay in 4th till you get to about 75 before you shift to 5th.

Pretty much my cars 5th is only usable when you are up around 80 mph. I plan on putting some lower gears in and have been thinking 3.20-3.55. I'm not sure just yet which ones, but after I put them in I will be going to the drag strip over near Baton Rouge and seeing what she will run.

What is y'alls suggestions on a good street/strip gear? I'm leaning more to 3.20 to keep my highway rpm under 3000, the 3.55 will keep my 80 at 2950 rpm. What do you guys think?

Just to let y'all know 80 is the normal flow of traffic in Louisiana on i10 and seems to be the same on i680 in California.
69 mustang coupe, 250 .030 over, forged pistons, port & polished CI AL head 54cc's 10.25CR, 280/280 Clay smith cam 1 degree advanced, 1.6 adjustable rockers,
Re curved DSII, MSD AL6, CI Intake, FITech 400HP fuel injection. T5 trans, 8" rearend w/3.80 gears, Eaton trutrack.

69stang_250
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Re: Gear suggestions

Post #2 by 69stang_250 » Sat Dec 24, 2016 12:04 pm

Sorry 3.25 gears were what I meant.
69 mustang coupe, 250 .030 over, forged pistons, port & polished CI AL head 54cc's 10.25CR, 280/280 Clay smith cam 1 degree advanced, 1.6 adjustable rockers,
Re curved DSII, MSD AL6, CI Intake, FITech 400HP fuel injection. T5 trans, 8" rearend w/3.80 gears, Eaton trutrack.

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powerband
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Re: Gear suggestions

Post #3 by powerband » Sat Dec 24, 2016 2:26 pm

The T5 overdrive 5th ratio for non-turbo 4's was typically 1:.79 compared to V8 T5's - 1:.68 ratio. I run V8 T5's in my 250 powered 61 with a 3.80 axle rear and 63 with 170 and OEM 3.50:1 axle. The 3.80 and .68 OD 250 and 170 with 3.50 rear and .68 OD are well matched with a little more 5th gear use with 3.80:1 than with the 3.50 rear.
For interstate cruise with the .79 OD ratio I would keep 3.50:1 or higher gearing like the 3.25 you mentioned.
But the 4cyl T5's First gear is 3.97:1 vs the V8T5's 3.35 or 2.95:1. 3.25 or 3.50 rear gears may make first gear lower than useful ... .

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Re: Gear suggestions

Post #4 by bubba22349 » Sun Dec 25, 2016 4:50 pm

I don't know that 3.25 would make much of a differance over your 3.00 you have now. Most of the T5 cars stock ran a 3.08 so you should be close depending on your rear tire diameter. What size tires are you running on the rear? I agree that the 4 cylinder T5 trans gearing probally isn't ideal for a 250 engines torque. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Gear suggestions

Post #5 by xctasy » Thu Dec 29, 2016 5:23 pm

What PB said

viewtopic.php?f=76&t=73629


a 1352-11-209 trans. The gears installed are 3.97 2.34 1.46 1.00 0.79




Youre probably too young to remeber Ollie North taking the 5th..




Read this....its why your gearbox has the strange ratios. The early 5 speed gearbox was not a T5, but a converted Hummer 4 speed with an overdrive slapped on. Fords overheated slide rule enginerring permeated all the ratio selections...as long as it added 3 or 4 mpg to the highway figure, who cared if it lost 1 mpg in the city, and had "Granny low" ratios that allowed it to idle in traffic without moving. They kept those dang ratios, and everyone commented on them,

in Europe,

https://www.flickr.com/photos/triggersc ... otostream/
https://www.flickr.com/photos/triggersc ... otostream/

Australia (That Wheels post above where they dissed the Thunderbird Turbo Coupe and 87 Mustang GT 5.0 5 speed),

and the US(Where they moaned more about the gearshift than the ratios).

http://www.caranddriver.com/reviews/198 ... eed-review
http://media.caranddriver.com/files/198 ... l-1981.pdf


Mariners use a 3 way fix to avoid dead reconing, so there are some guidlines to help you using a the tallest top, and lowest first gear recomendations form Past Precentant form the Ford Motor Companies 1978 to 1987 cars in the 2.3 to 5.0 liter capacity range in 2450 to 3300 pound compacts.

1. To work out the highest possiable top gear ratio gearing, you take the axle ratio, and times it by the 5th gear ratio.

Then look around for your info.

Fords highest geared US car was the 225 hp Mustang 5.0 with AOD or T5, 2.73 axle and 0.68:1 top gear some years. With a loaded tire, the diameter was normally 25.1". It had a roller cam which could vary a whole heap depending on grind, and Ford never told the factory specs, but its know to be for the speed density 5.0 litre H.O. approx 266 DEG. ADV. Duration, 210 DEG. @. 050" and .444" Valve Lift for Intake & Exhaust. LSA are all 115* and valve overlap is 36. Later,they went to a cam with the advertised intake duration increased to 276 degrees and infeered 0.050" duration was increased to 214* with a softer ramp opening. The exhaust valve opening/closing events remained basically unchanged when the MAF controlled engine came out.

Overall highest gearing ever was 1.86:1, or 40.16 mph per 1000 rpm.

At 80 mph, 1992 rpm in top,
2929 rpm in next gear down (3rd for AOD, 4th for t5)

Highest ever axle ratio was the Fox body line of cars. With C4 3 speed auto, the 115-120 hp 1980 4.2 255 V8 Mustang, it had 2.26:1 axle gears that year. All these cars had a stump pulling 244 degree tractor camshaft

With that years 24.53" loaded diameter tires, it did something like 31.87 mph per 1000 rpm, or 2510 rpm at 80 mph.

On the big Thunderbirds and Cougar XR7's they downgraded it to a 3.08:1 with C4 or optional AOD.

On the smaller Foxes, 3.08, and 2.47 and 2.73 ratios the next year as the gearing was really too tall, and there had been complaints.


Your current 0.79:1 5th and 3.00 axle with your current 24.5" tires matches the over geared 1980's Mustangs at 80 mph.


You can actually go taller than that, but you have a 278 cam.

Up to a 2.29 axle ratio if you want with that 4 cyl 0.79 5th, and get a 1.81:1 over all 5th, and have about, I don't know, 1992 rpm at 80 mph like the Mustang 5.0's did.


You can go as low as a 3.7:1 axle ratio,

Your 5th would be 2.92:1 overall, or 3206 rpm at 80 mph
Your 4th would be 3.70:1 overall, or 4058 rpm at 80 mph.


Now. lowest first gear ratio is has traditionally, on overseas Fords, been governed by Ford Australias internal memorandom from 1985 to 1992 when the new breed of in line sixes with Single Rail 5speed received crticism from Wheels Magazine and boat towing Austrlains and Kiwis. The Single rail 5speed of 1982 came out with the same gearing as the Rover 2600 and 3500 5-speeds, and on the 3.3 Falcon and 2.6 liter Rover, the 3.22:1 first gear was too tall with the 3.23 and 3.08:1 axle ratios.

Overall first gears were then downgraded to 3.47:1 to avoid customer compliants, or you couldn't pull your 17 foot boat trailer up a 11% incline with you tow hitch equiped Falcon or Rover six. Holden found the 3.08 and 3.22 were just fine in its lighter Coomodores.

That set benchmark as (3.22 x 3.08:1) or 10:1 overall as the tallest first gear for a Holden I6, Ford used a 3.47:1 first gear with a 2.77 axle on the 1986 to 1992 250 T5 gearbox sedans, pickups and wagons. 9.62:1 axle.

For the 3.3, they downgraded to a 2.92 axle with 3.47 first for 10.13 overall. Customer complaints with 3.3 manual's happened at the 10.4 to 9.6:1 overall first ratio, and plenty of 3 speed column shifts had 2.95 overall first gears with 2.92 axles for a 8.6:1 first.

Lowest? Well, from 1978 to 1987 Ford used 4.05, s, 3.97's with 3.45 axle ratios for the 4 and 5 speed 2.3 fours in Foxes and Rangers,
13.7:! over all

For 1981, IIRC, a 4.05 in first, 2.43 in second, 1.48 in third, and 1.00 in fourth and 2.47 axle ratio for the last Borg Warner T4 3.3 four speed in Mustangs and Capris. Same ratios as the later 2300 cc Hummer. There was no 1982 or 1983 four speed option for the 3.3 Foxes. For some reason, no 0.82 overdriven 5th like the 80-83 2.3's got, which gave a 9% boost in mpg with a 9% rise in top gear ratio in the 2.3 Highway MPG figure. 3.08 overall in the 4spd 2.3, 2.83:1 overall in the 2.3 5 spd with a 3.45 axle

10.00:1 over all first for the 3.3, 13.97 for the 2.3 5speed.

By those Ford US strictures, back anaylsis gives you a 3.45 axle ratio as the lowest gearing, and a 2.47;1 axle ratio as the highest with a 4.05 :1 first gear.


Its your car, and everything is a delicate blance between dollars, performance, and common sense.


My recomendation

Don't scared of going to the drag demon axle ratio's of 3.55's or even 3.7's.

You don't have to ever use 1st,

and you've always got a 27% over drive!


If it was my car, and I had to use the 4 cyl T5, I'd take a leaf from Varillux

viewtopic.php?f=1&t=71381&p=548006#p548006



and FirstFox's book, who had a turbo 3.3 Fairmont with stock 256 degree cam, 2.73 axle and 0.72:1 T5.

His overall top was 1.96, and he got 32 US mpg.

Some where between the two. Don't fear the gear!

You car has a 278 degree cam, and won't like too much more than what you have now for overall top, so you can even go down to as low as 3.7:1 and just not use first gear!

I've used 3.7's in an Aussie Valiant Charger with 390FE Autolite 1.33 2-bbl carb, headers, Hemi 265 in line six with a 351 Cleveland Single Rail 4 speed close ratio gearstack of 2.42/1.78/1.26/1.1:1 ratios and found it was fantastic,

but didn't like 4200 rpm at 80 mph.

But 3300 rpm at 80 mph with a 0.79 5th would have been real nice.


With 3.7's, your 2.34 2nd gear would be about the same as the 2.32:1 first gear on that 290 degree cam shaft Boss 302 close ratio 4speed and 3.91:1 axle ratio combo I posted on your Youtube link.

As the Aussie circuit racer Dick Johnson said in 1985 when stuck with the wrong homolgated axle ratios in his 5 speed Mustang Racing 5.0


"NO BODY SAID YOU HAVE TO USE FIRST!"


I often think about the old U shift wide ratio 5 speed 4 cylinder gearboxes, like the 80 to 83's had, same deal.

1980 RAP_AA_DA24_E0ZR_AA_ 1100
1981 RAP_AG_LB27_E1ZR_NA_ 0658


had nearly the same ratios.Just that they topped out at about 205 lb-fts, so they were only used on engines up to the 2.3 Carb turbos, which at best had around 5 lb-ft less than the 3.3's 155lb-ft.

Image

I'd say Ford was just so interested in Laboratory dyno FTP75 EPA figures without customer complaints, so a wide ratio 5 speed did it.

A car in a lab test can't stall, and has to do the same thing in the test it did brand new at an aged 50000 miles. So that gear spread was a solution to getting fair fuel economy in the City cycle, and reasonable emissions. In the old days, something like a close ratio 289, 302 or 351 with a close ratio Toploader, it wouldn't have a hope in passing the Federal sniffer test with such a tall 2.32 first and some of the more common 8 and 9" axle ratios.

So although the Pinto and Ranger had similar wide ratio gearboxes, it was really the 1980 cars that kept the wide ratio theme alive.

Three examples, namley


1. the 1980-1983 87 hp 2.3, Tremec T140VS, a Mexican made Hummer based gearbox with a Ford stamped case.

Ratios 4.05 in first, 2.43 in second, 1.48 in third, and 1.00 in fourth, 0.82:1 in fifth, 3.45 axle

2. 1980 94 hp 3.3, EA code wide ratio SROD gearbox

Ratios 3.29 1st, 1.84 2nd, 1.00 3rd, 0.81 4th, and 3.08 (quoted as a 2.49 final drive in Ford promos)

3. The 1981 91 hp 3.3 , BW T4

Ratios 4.05 in first, 2.43 in second, 1.48 in third, and 1.00 in fourth, 2.47 axle.

Notice how they changed to the lower numerical axle ratio, and went to the similar to 4 cyl higher numerical gear ratios?


Youre in the same company. Your 4 cylinder T5 gearing is a hangover from that era.

I think you shouldn't be scared if forgetting first entirely, and going down to a 3.55 or even 3.7 axle ratio


*PS, although it probably doesn't matter here, the T4 ratios were the same as the Jeep and T4C Chevy, and 4 cyl T5
4.03 2.37 1.49 1.00,
NOT
4.05, 2.43, 1.48 1.00 (The 5 speed RAN gear ratios)
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Re: Gear suggestions

Post #6 by 69stang_250 » Mon Jan 23, 2017 12:33 pm

Well after driving it a bit, I can say that the car rarely gets out of 4th gear, but is still very nice on the interstate.
Here is a good question and will harp me decide on gearing.
I do know this is very subjective based on the engine, driver, weight of the car, tires, and many other things, but what would be a realistic E.T. Time drop if I were to go with 3.80s and install a posi?

The car is plenty great for driving around town right now and it does not hesitate at a stop sign by any means.
But, I do want to get this car running as close to the high 13s as I can.
69 mustang coupe, 250 .030 over, forged pistons, port & polished CI AL head 54cc's 10.25CR, 280/280 Clay smith cam 1 degree advanced, 1.6 adjustable rockers,
Re curved DSII, MSD AL6, CI Intake, FITech 400HP fuel injection. T5 trans, 8" rearend w/3.80 gears, Eaton trutrack.

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Re: Gear suggestions

Post #7 by edgewood bronco » Mon Jan 23, 2017 9:32 pm

Thanks, Xctasy for an awesome post. I'll surely be coming back to that on my next project car.
62 F100 223
66 Bronco 200; autolite 2100 2 bbl conversion: Lovin' it!

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xctasy
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Re: Gear suggestions

Post #8 by xctasy » Wed Jan 25, 2017 7:47 pm

69stang_250 wrote:Well after driving it a bit, I can say that the car rarely gets out of 4th gear, but is still very nice on the interstate.
Here is a good question and will harp me decide on gearing.
I do know this is very subjective based on the engine, driver, weight of the car, tires, and many other things, but what would be a realistic E.T. Time drop if I were to go with 3.80s and install a posi?

The car is plenty great for driving around town right now and it does not hesitate at a stop sign by any means.
But, I do want to get this car running as close to the high 13s as I can.



I have a gear ratio program that horse trades MPG, MPH, and ET.

Its based on the best info from English (David Vizard's Car Craft experience), New Zealand, Australian and US practice.

You have that info already from my previous recomendations of a close ratio 5 speed gearbox with 3.73 or 3.55/3.50 gears.

That is the total answer.

But if you wanna see inside the recomendation process, then here it is:-

Horse trading:

1.mpg at 62 mph,
2.verses top speed
3. and 1/4 mile ET.

All my previous recomendations are based on it.

Ak Miller used this kind of prcess to get 35.6 US Mpg out of a 1-bbl 1967 200 Mustang in the MobilGas Total Economy runs from 1957-1967. So I just studied his life work...Ford engineering technician style. Total Inovation by the smartest engineers in the world, FoMoCo Dearborns Elite!

It runs of the It is based on the Index of Thermal Efficiency, found in French Grand Prix and English RAC litrature by Hodges, and the Total Economy Run variation by Snook and Bowland/Grippo Meqasquirt assumption that maximum fuel economy comes form over gearing the top gear, and then finding another ratio back from top that maximises 1/4 mile trap speed form the Moroso flywheel net hp figures.


You run it through a computer program. Kustom Bitz from Australia used to post one, but mine is based on the older school kinds the Aussie and US and English used.

Heres a run I did for a 4.2 liter V8....

http://vb.foureyedpride.com/showthread. ... eded/page2

xctasy wrote:That's what I'd expect. You can see the old CAFE numbers on the net, and drive reports show that at 55 mph, a 4 speed manual 3.3 liter 1980 Capri used to get 30 US MPG flat, and 22 mpg diven with economy. Any time else, it'd drop to 16-17 mpg.

Image

I've studied this at length and have three answers. Through the discipline and information on these old Ford and Fox engine combinations, the Corpoarate Average Fuel Economy (CAFE) average fuel consumption figures showed that it is possible to do a fuel consumption prediction for flat roads.

It was here that I learned there are many primary factors for mileage.

Power to weight ratio
Engine tune (Idle speed influences, ignition, HP per liter)
Gear ratio, tires, and aerodynamics
Climate (warmer climate uses less fuel)
Driving style (getting optimum mileage takes skill)
Terrain (flat terrain gets a lot better mileage than hilly terrain)

I have a computer simulator which calculates field US miles per gallon given some basic details. I've used it to forecast different miles per gallon for different engine combinations. And then backed it up by realworld testing.

It stems from an argument that arose in the early 80's when Chrylser Australia sold a four 1.6, 2.0, 2.6 and 4.3 liter sedans, and they all got the same real world fuel economy figures. Wheels May, 1980 found no difference in 2.6 vs 2.0 fuel consumption, and then the blunt old 3200 pound 4.3 liter Electronc Lean Burn CM Chrysler Valiant posted US 26.4 mpg (33 imp mpg) at 62 mph and used to get 21 US mpg (26.2 imp) city to higway.

Image

The adds in Australia and the United States were crazy. Fords Mustang 2.3 with T5 got 38 mpg at 55 mph,
Image

while the Aussie 3.3 Cortina got 28.2 mpg US (35.3 imp) at 62 mph

Image

Ford Cortina verses Sigma verses Faclon verses Valiant fuel economy wars were extingished when the Total Economy run came out.

adds


The three points are:-

1. In 1978, Ford started responding instantly to CAFE regulations by making its cars

a) 20% slicker through the air (better coefficent of drag, reduced frontal area through downsizing, 400 hours of wind tunnel desgin for every new design from 1978 onwards), and
b) over gearing everything 25%.

The areodynamics results in a huge reduction in engine power needed at speed, and at 65 mph, a 25% reduction in engine revs needed results in a 8% reduction in fuel use. So SROD's, 5 speed over drives, and the Fox body automatics with Moon Shoot gearing were how Ford got the 25% reduction in engine revs. This was the era of the 25% (0.81 and 0.79 in the SROD 4 and 6 and T5), 39% (0.72 in the SROD V8) and 49% over drives (0.67 in the AOD 4 stage), and a 50% overdrive is enough to save 15% in highway miles per gallon.

Ford did this because maximum fuel economy happens when gearing and capacity is optimised to the car... a modern Chevy, Ford or Mopar 6 liter capacity engine can match a 4.2 if its geared right, and the Corpoarate Average Fuel Economy figures 1981 5.8 LTD got better economy than the 4.2 or 5.0 LTD.

2. Due to the need to mandate stoichiometric air fuel cruise ratios in the Federal high way and city emissions cycle, some 1, 2 and 4 bbl carb enginess seem to do better than EFI for MPGS on certain engine combinations (300cube /4.9liter F100 and F150's verses a 4.9 EFI or 5.0 carb or EFI spring to mind), especailly when there is a 4-bbl or EFI with 30 or 65 more hp...In the old days before closed loop and open loop EFI, some 1 and 2-bbl engine combinations met the Federal emission manually at leaner than 14.7 or the oygenated 15.2:1 that is stochimetery, and this allowed them to stay out of the later 12.5:1 open loop air fuel ratios. The modern 3 way cat, feedback system on oygenated fuel doesn't hurt the fuel economy one bit, but they have some inbuilt limits the old engines don't, and occassionally, the later EEC managed engines suffer just as many inservice problems as the early 1978 to 1982 engine. After 1983 in all states, feedback non lean burn engines became mandatory, even if they were called ELB, High Swirl, or Lean Burn, they weren't ever lean burn again because 14.7:1 became the ideal air fuel ratio. EFI engines can run at 22:1 in low load situations if the exhast valves are tough enough, but the electronics after 1983 forced car makers to adoped non lean burn air fuel rations, and so every engine is 10% less efficiecnt than a non emissions, lean burn engine. So some of those 1978 to 1982 engines could really fly great fuel numbers

3.The ideal gearing for economy was cracked back in th 50's but we had to wait till the late 70's and early 80's for the formula to be re-arranged for best miles per gallon for a given average cruise speed. It is based on the from the Index of Thermal Efficiency, found in French Grand Prix and English RAC litrature by Hodges,

and was revised in 1980 for the Australian Total Economy Run, to use the average frontal area and drag fact for a lates seveties, early 80's car. See http://www.snooksmotorsport.com.au/index.php?option=com_content&task=view&id=31&Itemid=39

Here is my computer out put for a 3.3 and 4.1 engine in a Fox Mustang, using the Snook variation on the Index of Thermal Efficiency


Image



That last one is like a 1979 to 1982 4.2 V8 with a 1.83:1 diff ratio. If it was lowered to the factory 2.47 or 2.26, and rerun with a 4.2 engine, the fuel consumptionat 62 mph would be 22.4 or 23.7 mile per US gallon at 62 mph.

I re-ran it with the 4.2 4-bbl and AOD with 3.45 diff and got 23.4 US mpg at 62 mph. Image


The above Capri 4.2 with AOD combo with a 2.31:1 overall final drive would have done pretty well.

The lock-up clutch sure would have helped too. If you can employ the lock-up, there is a potential saving beyound that, maybee an extra mpg at 62mph.

Oh, and a 2.3 with T5 running just a 3.45:1 diff gets 38.6 mpg at 62 mph using the same information. The point is that as an engine gets bigger, it can carry higher gearing, and to do that, the camshaft duration and lift can get dropped. A 4.2 runs 244 degrees of duration and has maximum power and195 lb-ft of torque at 2200 rpm, which is very low in the rev range. At 100 mph, its only turning 3400 rpm with 2.47:1 gears, so its pefectly geared for 115 hp.

It comes from the above formulae above, and it works.
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Re: Gear suggestions

Post #9 by xctasy » Thu Jan 26, 2017 7:31 pm

Okay.

First was the MPG preach...so with a 0.79 5th you can go as high as 2.29 :1 axle ratio if you were silly enough for a 1.83:1 top.

You like the 0.79 with 3:1's, which is 2.37:1 top.




Second step is the idealised Top speed.

Here's how this is done for Mike1157



http://vb.foureyedpride.com/showthread. ... &p=1828597

xctasy wrote:From your earlier info, your car has 3.73's

4R70W gearset is , 2.84:1, 1.55:1, 1.00:1 and 0.70:1 in top.

The rear Sumitomo HTR Z 315/35ZR17's are 25.68" unloaded and is incorrectly rated at 787 revs per mile...its actually 804. Based on my experience with contact patch at whatever psi you run in them, the loaded rolling diameter is in fact 25.13 ". Its always around 2.2% less than the book value dameter, BF GoodRich and Michelin have confirmed this over the last 20 to 100 years of raidial construction.

At 0.70 in top, thats 28.628 mph per 1000 rpm, or 2446 rpm at 70 mph, less if slipping.

So your right on the basics.


Incidently, tire tread depth is IIRC 0.5", so rpm could go up to 2546 rpm as the rapidly incinerated Lizard warms its tires up on a regular basis...to become...SLICKS!.

Good enough for 157-163 mph at 5700 rpm.

Given your excellent leakdown figures and low oil consumption, and open engine breather that won't be putting the PCV fumes into the intake tract, you can pop a 112 mph 1/4 mile at 5700 rpm through the traps.

Once you get the detonation threashold under control, I'm sure you'd be able to run 11 pounds.


With a computed weight from your vehicle of 3200 pounds all up with you,

You'd only need 369.51 rwhp to do sub 11.96's at 112 MPH trap speeds in 3rd at 5700 rpm.


In your case, I say the Sebring short ratio 5th gear is always the best. Due to the Aston Martin DBS, essentially a sanatized GT Zagato for the street.

and 3.4/3.8 D-type Jag gearing ratios for Le Mans, and the 13 second capable E49 Chargers issues with not getting high enough gearing for a good top speed. 132 mph was 1000 rpm into the red sector, so the E49 IS your goal post, with a little ZF 5-speed gearing thrown in

Now the solution process for optimised ET is like this

4.10:1Axle Gearing For Engine Power of 515 flywheel net HP Small Block Ford 347 1983 rEPLICA nOTCH Mustang from London UK's Joe Lounge

http://vb.foureyedpride.com/showthread. ... 4-56-gears

xctasy wrote:All important 112 km/h, 70 mph revs with 4.5% crush on a MT tire is 3581 rpm, no allowance for torque converter slip. You'd do 130 mph at 6700 rpm no sweat with your C4.


There are other better xls spreadsheets around, I did mine in 15 minutes, and mine is designed around manual gearboxes, with variable ratio steps which are out of sync without some input, but the 4.10:1 and 275 60 15 rough and ready reckoner is here. The drivedrain loss is based on an optimized torque converter. The race tires have a 4.5% loaded wheel diameter crush, not 2.2 % as is common with a set of Pirellis, Michelins or whatever other non MT modern radial you use, but its close enough.


It still has 302 ci listed, and assumes the AOD with my tallest manual 1st gear ratio no different to 2nd gear, and you won;t have a 067:1 overdrive. but if you take all that out, you have the info with your tires and your planned diff, and a conservative 2.2% wheel crush.

Have fun. I ran this on the 250 hp 1955 3.4 D type Jag with 3.54 axle and also the 265 hp 1957 185 mph 2.53 axle 3.8 D type, and the math is flawless. And that's got me thinking....You blQQdy Poms rule the world for making insanely fast cars because you guys talk to one another over warm beer in cold weather with polite conversation. Over here and in the NZ and Aussie, we still think cubic dollars, cubic inches and container loads of gear, but we trail and error it a lot more, you guys seam to understand the basics better and dial in the variables very well. For Joe & Co to do a car like that with so little access to speed shops speaks volumes of Peter and your band or bros abilities with spec-ing out a great small block 347. Your info from your Blighty http://www.outlawstreet.co.uk web site is very cool.

Well done!

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FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
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Re: Gear suggestions

Post #10 by xctasy » Thu Jan 26, 2017 8:22 pm

Option 1 You are best served by 3.7's or 3.55"s with a close ratio T5Z and Sebring 5th.



Option 2

With your stock wide ratio 4cylinder T5, just use 3.25's . 3.20's are a 7.25"ratio, not common.

You stay in 4th with the 3.00's, and the 5th is only like 85 mph.

Gearing each down just 18% will allow you to really use 4th instead of 5th, but still use 5th when ever.

The savage low 1st wont be injured as much with the 3.25's, and it will cope.



How I worked it out....


I do two people up acceleration simulations with a half full tank, so I add 404 pounds to your stock start line weight.

A bench mark I use.

Idealised flywheel hp for a 3864 pound 350 hp net car is actually making 277 hp at the wheels, for 13.95 pounds per hp; that gives 14.02 sec 1/4 mile at 95.55 mph.

This a 1971 Boss 351 with tube headers, an Australian solid lifter cam, or similar to the modified, non stock Hot Rod 13.9 second press car.

Or the Aussie Phase III Falcon in this music video...https://www.youtube.com/watch?v=kLBNnGxDgtY

The car that bet both the 351 C 4V HO and Boss 351 was the E49 Charger.

It made 295 hp net, or 233 rear wheel hp in a 2910 pound car with a 3314 pound start line weight.


idealised ET / MPH is 14.11 seconds and 94.94 MPH two up

If its a manual, take your net flywheel hp, and divide by 1.264

then use this website to run the idealised rear wheel hp to 1/4 mile ET and trap mph.

http://www.wallaceracing.com/et-hp-mph.php

Drop the gasoline and the passenger, and its ET / MPH is 13.75 seconds and 97.45 MPH, 3064 pounds at the start line.

Everyone races with just the driver, right?

Summary:-


The stock T5 gearing with 3.25 axle is all you need is to haul through the traps at 97.45 mph at just a touch above a 5500 rpm red line, maybee more. In 4th, thats 5020 rpm.

In your 1.43:1 third, 6016 rpm. That's a little too high for a 250 I6 normally, but you'll be right.

That assumes you'll get 295 flywheel hp with your CI head and 4-bbl 670 cfm carb. I know you'll be dang close....

Oh, and based on all the drag factor and frontal area and tire sizes, you'll get about 135 mph at 5500rpm in 5th.

When you can afford a T5Z close ratio gear set, you can drop down to a set of 3.7's or 3.55"s


Your bench mark is the wide bore spacing 265 Hemi, an engine quite unlike any other ohv I-6


See viewtopic.php?f=13&t=65739
Last edited by xctasy on Fri Jan 27, 2017 4:07 am, edited 1 time in total.
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XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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Re: Gear suggestions

Post #11 by xctasy » Fri Jan 27, 2017 2:59 am

And finally, if you want to know how to gear a car for more than 141 mph and sub 14.6 second quarter miles, then the Aussies have been doing it from 1971 to 2016...

http://vb.foureyedpride.com/showthread. ... ca-I-built
xctasy wrote:Probably right, although the Fairmont GT is one ULTRA rare son of a gun, one of a now only 19 in existance South African market export model, previously exported to the republic as a "re-coded" Falcon GT with Fairmont apointments as well as a pretty stout 300 hp SAE Gross 351c 4V 285 hp M code cam . A prety hard animal to tame. Manual cars were hydraulic lifter 15.5 second quarter milers with a 130 mph top whack, with that years 1971 GTHO, you got 300 degree solid lifter 350 hp SAE net engine with 14.6 second quarter mile capabilty, 13.9 secs with drag racing gears. Okay for 144 mph on the overun past where the 6150 rpm rev limiter kicked in.


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Again we chewed up the miles and spat them out. In remarkably short time we were striking the long straights of the Hume about 140 miles north of Melbourne, and with the speedo steady on 125 mph I squeezed down still farther on the accelerator as the ribbon of road speared straight ahead.

The shaker heaved in the bonnet, the car sort of shrugged and the nose rose up even further from the road. It might have been a tiger kicked awake; the noise alone said that. The speedo needle went determinedly around the dial, and soon it was showing 144 mph. A true 141 mph.

But whoa! The engine started missing; fluffing and farting. For God's sake - the rev-limiter! we'd run right up to it. In top gear. A full 6150 rpm (the tachometer actually said 6700rpm; it was optimistic).

And if I kept my foot hard down that hoary great V8 just kept thumping away against the cutout, straining for even more. So once Uwe had shot some pictures over my shoulder, to prove it really was happening, I lifted off a fraction to back it off from the limiter at a neat 140 mph.



They picked up around 40 net horsepower over what Mick Webb dynoed in 1972, that was 350 hp. The 1972 RPO83 Phase Four made it to 170 mph at 6800 rpm claimed by Bill Santuccione or the similar 170 mph top speed Howard Marsden and David Bowden have claimed at 7200 rpm...that car, could do 140 mph at 7200 rpm in 3rd gear with the 6200 rpm rev limiter un hitched.

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141 MPH at 6200 rpm (quoted from three other sources as 141 mph, but 144 indicated)
14.6 sec 1/4 mile at 95 mph
1971 Phase III GTHO FALCON 351,
350 hp net at 6150 rpm, (Mick Webb, Hot 302S AND 351s 1990)
Cobra Jet 428/Boss 302 4160 780 cfm Holley 3310 4-bbl vac sec carb
300 degree solid lifter, 505 thou lifft cam
H-M Tri Y headers and dual exhasts
3.25:1 axle,
ER 70 14 tires,
Wide Ratio Top Loder 4 speeed
Ist 2.78
2nd 1.93
3rd 1.29
4th 1.00:1

147 MPH at 4600 rpm
14.64 sec 1/4 mile at 95 mph
1985 Brock HDT Holden Calais 5.0 C Director
https://www.wheelsmag.com.au/features/c ... et-thunder
228 hp net at 4800 rpm,
725 cfm Rochester 4MC
304 cubic in Big Valvewith stock 276 degree XT5 Holden camshaft
H-M Tri Y headers
3.08:1 axle,
Pirelli P7 225/60 15 tires,
Ist 3.35,
2nd 1.93
3rd 1.29
4th 1.00,
5th 0.73:1

146 mph at 4550 rpm
14.9 sec 1/4 mile at 92 mph
1997 EL Ford Falcon GT with 1997 Explorer Truck 5.0 with GT40P heads and GT 40 intake
https://www.wheelsmag.com.au/features/c ... e-autobahn
254 hp net at 4700 rpm
Non OBD II EEC V Engine management
5.0 Exporer V8 with big valve GT40P's and the E303 variation, non 256/266 cam
H-M Tri Y headers
3.27 axle
245/40R17 Yokohama A510 tires
BTR Borg Warner Ion LE 97 4stage AOD
Ist 2.39:1
2nd 1.45:1
3rd 1.00:1
4th 0.67:1

157 MPH at 6150 rpm (quoted from three other sources such as Dr John Wright in Wheels 1983 as 156 mph.Unrev -limited, 170 mph was at 6700 rpm, as Bill Santuccione, the late Howard Marsden, and David Bowden [owner of two] have indicated is possiable)
1/4 mile unreported, but faster than 1971 car
1972 Phase IV GTHO FALCON 351,
390 hp net at 6150 rpm, (Ford Special Vehicles Bill Santuccione, Australian Muscle Car )
Cobra Jet 428/Boss 302 4160 780 cfm Holley 3310 4-bbl vac sec carb
300 degree solid lifter, 505 thou lifft cam
H-M Tri Y headers and dual exhasts (bigger diameter than 1970-1971 GTHO)
3.00:1 axle,
205/70 VR 15 Pirelli CN 36 tires,
Wide Ratio Top Loder 4 speeed
Ist 2.78
2nd 1.93
3rd 1.29
4th 1.00:1

185 mph at 6600 rpm in 5th, not 6th gear
1/4mile 12.8 sec at 111 mph
2014 Ford Falcon FPV GT-F
https://www.youtube.com/watch?v=0zVTMAOiL-8
470 hp at 6000 rpm ( 537 hp at 6000 on overboost)/420 lb-ft 2500 - 5500 rpm
5.0 litre supercharged Boss V8
3.73 axle
275/30 R 19Y tires
TR6060 6-spd manual; or ZF HP26E 6-spd auto
1st 2.98 (11.11 overall)
2nd 1.78 (6.64 overall)
3rd 1.30 (4.85 overall)
4th 1.00 (3.73 overall)
5th 0.71 (2.65 overall)
6th 0.55 (2.05 overall)
Image
XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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Re: Gear suggestions

Post #12 by xctasy » Tue Jan 31, 2017 4:45 pm

After all that, it was Dan who found out the right ratios back in 2011.

https://dev.fordsix.com/viewtopic.php?f=76&t=65534

rocklord wrote:
rbohm wrote:8) i suggest going big, get the T5 you wont be sorry with two extra gears, one being an overdrive. it also allows you to run a stiffer rear gear, say a 3.55 or 3.73, while maintaining decent rpm levels on the freeway.


If you go as rbohm suggests and upgrade to a 3.55 or 3.73 rear end, make sure to use T-5 out of a V8, which has the 3.35 first gear. If you get a T-5 out of a 4cyl, you can go with a 3.00 rear axle, and have the same effective gearing ratios.

Here are the calculations to make my point. Make sure you look at the overall gearing between the transmissions in first and OD.

Ford 2.77 three speed Transmission
Overall Ratio with 3.20
First gear -- 3.29 -- 10.528
2nd gear -- 1.75 -- 5.60
3rd gear -- 1.00 -- 3.20
Reverse -- 4.46 -- 14.272

Ford T5 1352-162 4 Cyl Transmission 1987 WC
Overall with 3.00
1st gear-- 3.97-- 11.91
2nd gear-- 2.34-- 7.02
3rd gear-- 1.46-- 4.38
4th gear-- 1.00-- 3.00
5th gear-- 0.79-- 2.37
Reverse-- 3.70 --11.10

Ford T5 1352-169 8 Cyl Transmission 1987 WC
Overall Ratio with 3.55
1st gear-- 3.35 -- 11.892
2nd gear-- 1.93-- 6.851
3rd gear-- 1.29-- 4.579
4th gear-- 1.00-- 3.55
5th gear-- 0.68-- 2.414
Reverse-- 3.15-- 11.182

I have a 4cyl T-5 and 3.00 rear end gears for my Mustang. 3.55 gears wouldn't work for me with overall gearing of 14.1 in first.

Hope this helps.
Image
XEC Ltd ICBE's Inter Continental Ballistic Engines-
FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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