Which jets?

[hasa68mustang]

Ok, I SHOULD be getting the final parts today to start assembly of this turbo setup... but I have a couple of questions. I was wanting to know what jets I should run? and what size power valve? Thanks, Tommy oh and for the time being I am planning on running with the factory wastegate which is set a 7 psi...

 

[xctasy]

If you have a Propane Impco CA 300, or K&N or Does 10's or Turbo_Fairlane_170 style hat on the carb, then:-

stick with the stock 73 jets that came with the 500 cfm carb, and use the 6.5 power valve rather than the 8.5 it came with. Pump squirters and Power valve holes can stay the same. A turbo will require more fuel under boost, and since your carb is already bench calibrated for a rich 289 to moderatetly lean 390ci Ford 2-bbl, then running it as it was will be fine.

The float just has to be hard formed plastic called nitrophyl, and every 2300 series Holley carb runs very well sealed throttle bodies and throttle shafts, so that should be okay up to about 16 psi.

Does10s says that for a proper turbo for beginers, the total timing should be limted back from the 36 to 40 degrees stock down to something like 25 or 28 degrees. You can weld a limiting plate on your ignition advance plate, or add a small rivet to stop the advance plate opening fully. Check full advance at 3500 rpm is no more than 28 degrees when starting out.

The fuel delivery pressure is best controlled by a Summit supplied fuel pressure limiter (Moroso 4309), and boost reference the fuel pump like Linc 200 did.

All in all,

a) leave the carb rich, with nitrophyl float
b) reduce the total advance,
c) increase the fuel pressure

.

With 7 pounds of boost, the car should recieve a boost ratio of 1.4, which means your little 200 will behave like a 289.


For more reading, get the ancient 1980 or 1988 reprint of the SA Book, Holley Carburetors by Dave Emanuel, and read pages 69 to 71 on Blow Through Modifications.

You'll see that Americans had the right Holley Turbo information 23 years ago, and that all the guys with Turbo I6's (Does 10's, drag200stang) have just relearned whatwas lost during the years of the gas crunch!

 

[XFlow_Fairlane]

I am running a 63 jet right now but might be going down to a 62 or 61

your jetting should pretty much stay the same as you have it now....I would just go up a couple sizs (1-3 steps) just for saftey.

if you have anymore questions just PM sometime tommy....not like I am doing anything right now (no job and no school)

 

[hasa68mustang]

I have the nitrphyl (SP) float and jet extensions, and I ordered the carb hat that mustangaroo is running or at least very similar, I also ordered a greddy type s bov, both should have been here yesterday but the post office has this crazy holiday called the day after the new year off??!! so hopefully they will be here today... I have a goal to get the car up and running by the 14th as a local mustang club has a dyno day setup and you get 2 runs for 40 bucks and they are supposed to give you your a/f ratio paper deal thingy but I dont know how they measure it and if on my car without all its computers if I would be able to get it. But I doubt its going to happen, and if not I will be able to get my n/a hp numbers.

 

[hasa68mustang]

so doesn anyone know where you can get a powervalve? and ummm I think thats about it for now, I did get everything today so mockup and assembling begins soon!

 

[kirkallen143]

As for the PV, first see what vacuum you are running at idle, then take half and add 0.5 and that should put you in a safe margin when coming on boost. For example my vacuum is 19 - 20 Hg at idle, so I will start out with a 10.5 PV and experiment from there. I am starting with the 68 jets and probably boosted to 8psi for now. Good luck.

Kirk

 

[xctasy]

I'd not use the 10.5 if you were running a larger jet. I'd go down to 6.5, 5.0 or 4.5 power valve, which comes in only under wide oen throttle. You'll never gonna stave it of fuel with a Holley 2-bbl with V8-style jetting.

I think Linc200 was runing just one :!: 72 Holley jet when he made a low 13 second pass in his Turbo 200. He had one 1946 1-bbl carb and 16 pounds of boost, you guys have like two and half the boost.

Most stock 200's with a 500cfm carbs like a 65 to 68 jet, and a good restriction to the two power valve channel restriction holes each side of the power valve. Using WsaIII and Linc 200's fuse wire trick, it may be a good idea to insert some15 or even 20 amp fuse wire in there to ensure the engine doesn't die of too much fuel. Bearing in mind a stock instillation in a 390 cube 500 cfm carb had 73 jets, a 10.5 power valve may mean the engine is running like 10:1 air/fuel ratio, or equal to running a huge 81 jet .

Even if you guys were getting , say, a 130 hp flywheel hp with some really good mods, the turbo at 7 to 9 pounds wouldn't need to be jetted as rich as a 390 Ford. The boost ratio is only about 1.6 times a standard 200, which works out to being like a 327 at full boost. 130 hp with a 9 pound boost is like 210 hp at the most. Stock 73 jets can yield 350 hp on a really good 289.

As long as you advance the ignition to about 14 degrees static, and then restrict the total advance to 28 degrees at 3500 rpm, then you won't need to fuel it up that much.

The 200 just doesn't need that much jetting when you've aslo got two 60 size holes putting gasoline into the intake as well.

I'd look at Does 10s jetting and power valves, he runs a tiny little 350 cfm carb, and IIRC its not even using a 73 jet with over 300 hp at the wheels. A 500 can run as big as an 82 jet on a big block 2-bbl.


I may be a little 'anti turbo' at times (possibly its envy. I've never had more than 9 pounds of boost to play with in a tiny 2.3),

It doesn't matter how you get your boost, the carb doesn't need to leak fuel like an English oil refinery to make a good blast

Enjoy yourselves. Wheres wsa111i and his Innovate LM-1 air fuel ratio tester?. Perhaps we need to set up a rental fuel ratio tester at mates rates, and do our own R&D!

 

[hasa68mustang]

ok well I bought it from automotive engineering, it was 7 dollars and from summit power valves start at 14 if I remember correctly. and after my extensive "testing" I have gone a whopping 64 miles on a littel over a half a tank of gas... and I put in 14 gallons ontop of the VERY little that was in there... so if I put the power valve in I would get a little better gas mileage correct? at least for now?

 

[xctasy]

The power valve rule works fine if the carb is a recomended Holley carb swap.No-one from Holley has done a recomended swap yet for our 200's and 250's. So we use giant size carbs from V8's, and make them work.Those power valves are good recomendations if its a V8 or a 300 cube six. We have tiny engines sucking from big juicers.

In our case, even in a turbo, we are better off using a lower Power valve, so that its leaner for longer. The lower the number, the leaner it'll be during day to day running. When you stomp on it, it will still go rich, as rich as it would be in a V8, but it not as quickly as before.


Remember, when the vaccu drops, the champaign pops, and all the fuel rushes in to make your engine run well. On a turbo, the car must be lean most of the time, then become rich when the pedal goes down. Having a 500 Holley on a log headed 200 ensures there will be a good supply of fuel. If there fuel pressure is above the boost pressure, there will be heaps and heaps of gas on deamand.

The main jets can go right down to 68 without a problem before turboing. Without a turbo, I'd still restrict the power valve channals down with thick wire.

Even shoving two 40 thou or 1 mm thin wires in each restriction will still allow lots of fuel to go into the carb.


I'd still use the 6.5 power valve, becasue vaccum isn't going to be that good with a big 500 carb. The idle vaccum could be 2" Hg different with just a samller 350 cfm carb, so its important to run a low power valve number or the car will be way rich everwhere.

When you do get under da boost, you'll just need to take the wires out of the power valve restrictions on each sit in the metering block. 68 jets and 6.5 power valves are enough for 200 hp because the 4412 carbs channel restrictions are just H-U-G-E!

 

[kirkallen143]

The power valve rule works fine if the carb is a recomended Holley carb swap.No-one from Holley has done a recomended swap yet for our 200's and 250's. So we use giant size carbs from V8's, and make them work.Those power valves are good recomendations if its a V8 or a 300 cube six. We have tiny engines sucking from big juicers.

In our case, even in a turbo, we are better off using a lower Power valve, so that its leaner for longer. The lower the number, the leaner it'll be during day to day running. When you stomp on it, it will still go rich, as rich as it would be in a V8, but it not as quickly as before.


Remember, when the vaccu drops, the champaign pops, and all the fuel rushes in to make your engine run well. On a turbo, the car must be lean most of the time, then become rich when the pedal goes down. Having a 500 Holley on a log headed 200 ensures there will be a good supply of fuel. If there fuel pressure is above the boost pressure, there will be heaps and heaps of gas on deamand.

The main jets can go right down to 68 without a problem before turboing. Without a turbo, I'd still restrict the power valve channals down with thick wire.

Even shoving two 40 thou or 1 mm thin wires in each restriction will still allow lots of fuel to go into the carb.


I'd still use the 6.5 power valve, becasue vaccum isn't going to be that good with a big 500 carb. The idle vaccum could be 2" Hg different with just a samller 350 cfm carb, so its important to run a low power valve number or the car will be way rich everwhere.

When you do get under da boost, you'll just need to take the wires out of the power valve restrictions on each sit in the metering block. 68 jets and 6.5 power valves are enough for 200 hp because the 4412 carbs channel restrictions are just H-U-G-E!

You know, I did not think about vacuum with a bigger carb being lower. Well, I do have an assortment of PV's anyways and I do not intend to restrict the PVCR's, but it is neat to see what tooling with these carbs can do. Hell, I haven't even got the head back from the machinist yet (lazy,no-good for nothing @#$%^) and it has been 4 1/2 months that he's had it... I HATE TRYING TO BE NICE ABOUT THINGS THAT AREN'T SO! I guess that's what I get for sending it to a small hick town lazy machinists that's retired. The head will be in my hands next Thurdays, finished or not, this is his eighth last chance! Sorry, had to vent, thanks guys and gals.

On another note: if you are running boost on a holley, don't forget to eliminate the PV blow-out protector. You know that little ball with a spring under it in the throttle body plate...just drill the little retainer out with the corresponding size bit and it will pop out. This allows the carb to perform properly under boost.

Kirk

 

[addo]

Hey Kirk, I hear so many stories like that about your slack machinist.

Take heart in one aspect. It proves we really are a bunch of nice guys - or they wouldn't do it!

Maybe stop by his place, and start talking about your scaling back of the medication for Tourette's, and how your anger management therapist's on vacation, but at least you could renew your gun licences...

 

[kirkallen143]

NOW THAT IS A GOOD THOUGHT TO CONSIDER!

 

[xctasy]

Subtle, Addo, VERY subtle!

 

[addo]

I'm over subtlety. The madder I get, the more I overcompensate. Anyone who gets called "sweetheart" is usually inches away from a hiding.

- So, if I sound grumpy, it's nothing to worry about! If I seem nice - RUN!

 

[kirkallen143]

Tommy,
Really these are all safe starting points, but the real challenge is when it is up and running, the fine tune. This is when the vacuum/boost gauge is your best friend. Stage the rpm levels and record both vacuum and boost psi and rpm. It will determine when you want your PV to unload. Idle tunning starts first (primary jets), let it warm up at idle and then adjust your idle mixture to highest vacuum reading and then check your plugs. Black: rich, brownish-tan: right on, and whitish-spotted: lean. Take jets up or down in two points, at least.
Once you have established your plotting (rpm vs. vacuum vs. boost psi) it will let you know just when to open up the PV under boost to let more fuel in. Like said before, don't want to dump fuel in at cruise, only at WOT.
Example, say your cruise rpm is at 2500 and making 4psi at 10.5 Hg, you would not want a 10.5 PV or higher number, would be riching up when you don't need it. Again, At WOT, 8psi @ 5500rpm (and vacuum should be little to none) your PV should be fully open. Checking at WOT, warm the engine, make a WOT run (using safety first), immediately shut the engine off, without idling and check your plugs. The same colors apply to the plugs as mentioned above. If not enough fuel at WOT (first you will hear denotation) then you might have to drill out the PVCR's (stock they should be @ 0.0625"), but will probably not have to drill, they are a good size already for these sixs. That's on assumption since William is restricting his PVCR's and getting good results without a turbo.
These are just some of the aspects and there are others as well, it just takes alittle research and hands-on. I have blabbered enough for now, also a good reference is www.turbomustangs.com, lots of helpful folks.

Kirk