2V Dyno Results - Part 1 & 2
- Thread starter AzCoupe
- Start date
I think alot of you are missing the point of the testing. We were there to compare the gains from three different carbs, verses the stock 1V, when mounted to a log head using a 2-1 adaptor. That's it, nothing else. Our only concern was to make sure the A/F ratio was where it needed to be. Only the Holley needed to be re jetted, as the Weber and Autolite were fine. Hence we paid no attention to jet sizes in those two carbs.
Several years ago I ran several different combos thru Engine Analyzer 3.0 using some rough flow numbers on the late model log head. In every combo of cam, exhaust, and carb, the numbers always fell short of expectation. No single item added a great deal of power and even good combinations of parts showed meager gains. The bottom line was always the poor performing head. It was the weak link in every chain.
In the simulations, even small changes in the head flow on the intake and exhaust had big payoffs. This was confirmed on multiple real world cases where a 2V head swap alone, with no other changes, yielded 30-35 hp gains on the dyno.
I don't really think the carb opening is the choke point. It's in the intake and exhaust ports, especially the pocket under the valves. There a large valve guides cast in and a very poor transition from the machining to the casting. The exhaust is very restrictive and has a tight turn down to negotiate.
Without some porting, I don't think a 2bbl direct mount will have significant gains because the head can't support the additional flow, but I'm looking forward to any test results.
In the simulations, even small changes in the head flow on the intake and exhaust had big payoffs. This was confirmed on multiple real world cases where a 2V head swap alone, with no other changes, yielded 30-35 hp gains on the dyno.
I don't really think the carb opening is the choke point. It's in the intake and exhaust ports, especially the pocket under the valves. There a large valve guides cast in and a very poor transition from the machining to the casting. The exhaust is very restrictive and has a tight turn down to negotiate.
Without some porting, I don't think a 2bbl direct mount will have significant gains because the head can't support the additional flow, but I'm looking forward to any test results.
66 Fastback
Famous Member
I agree, and I think that is why all of the test results are very similar in magnitude despite the carb changes.
When Gene brings back the direct mount carb and head, will it be the same head, and will it be unported etc? If so, then it should be an apples to apples comparison of direct mount to a 2 into 1 adaptor.
Or will it possibly be a head with larger valves, different combustion chamber size, and possibly some porting?
Doug
I bet both statments of a direct mount compared to an adapter not showing an increase are totally wrong.
I run a direct mount & it is light years ahead of any adapter.
Prime example is jetting of the same carb on a direct mount compared to an adapter.
I feel the further testing will support the fantastic gains i obtained with the direct mount. Bill
I had posted this topic, but got no bites: http://fordsix.com/forum/viewtopic.php?t=52666&highlight=
I still think a progressive should not be mounted directly with the shafts running fore & aft. That would make the fuel distribution worse than it is on the stock log.
I still think a progressive should not be mounted directly with the shafts running fore & aft. That would make the fuel distribution worse than it is on the stock log.
wsa111":pi0n6xpf said:
You could be right Bill. It'll be interesting to see what the dyno shows vs. the simulations.
Well, we did PART 2 today. The cost of the dyno time adds up fast, so I hope the info is helpful, and appreciated.
We weren't able to test the DSII today as planned, as we couldn't find one. We checked with three different chains, and all three told us they no longer stock them, as they are now a special order item. That was disappointing, as I was really hoping to test the DSII vs. the DUI. Guess we'll just have to do it another day. As a result, I'm going to see if I can get the DSII and keep them in stock.
We wanted to test the high ratio rockers too, but that also had to be put off for another day, as I am currently out of ball and cup pushrods for the 200ci. I've had them on order for several weeks, but getting parts from this supplier is difficult, to say the least. I keep making phone calls, and had my fingers crossed, but no luck. Hopefully I'll get them next week.
We did test the DUI however. Again, this was on a 200ci with a fresh rebuild, a 264-112 cam, and headers. Keep in mind; the baseline Weber had no provisions for vacuum advance. Using the Weber baseline with the stock dizzy, we gained 15HP & 13 lbs of torque after installing the DUI. The Weber/DUI combo, over the 1100 and stock dizzy, gained 23HP and 10 lbs of torque, while the Holley/DUI combo netted 25HP and 12 lbs of torque. That's a 29% increase in HP.
One problem I noticed, is that the motor doesn't make much power down low, but takes off once it gets past 2500rpm. My guess is that the cam is retarded, maybe as much as 6-8 degrees, as it wasn't degreed when it was installed. Even if the cam is ground spot on, Clay Smith recommends installing them 4 degrees advanced (their cams are ground straight up), therefore it's at least 4 degrees retarded. I'm guessing even more based on how the motor was performing, as it should make a lot more bottom end power.
However he is going to replace the damper soon, as it has slipped considerably. At that time, he plans to degree the cam. Once that's done, I'd like to take it back for another go around. If I'm right, it will make a huge difference.
EDIT: I had to take a break for dinner. LOL
As for the carb test, we did the baseline last week with the stock 1100 carb. This morning, the Weber was already installed when we got there, so we were able to get right to it. We did our first run with the Weber, then pulled the stock dizzy and installed the DUI. After a run with the Weber and the DUI, we installed the Autolite 240cfm and did two more pulls. Next we installed the Holley 350cfm and did another run. Our finally pass was with an Autolite 245cfm, which I decided to bring along.
Remember, both Autolites were used carbs purchased at a swap meet earlier this summer, so we had no idea of their condition, or if they would even run. To our surprise both worked fine, however it was obvious that the 245cfm needed a rebuild. It also needed to be re-jetted as it was quite lean, however we didn't take time to re-jet as it was lunchtime and the guys were ready. Therefore we decided to call it a day. We got the info we were after using the first three carbs, so the last run didn't really matter.
SUMMARY: The progressive Weber made the least power, while the Holley 350 made the most. The Autolite 240 [1.01] & 245 [1.02] were in between, with the 245 making more, even in its poor condition. However, all the runs were within 2 HP and 3 lbs of torque. If I can afford it, I'd like to try an Autolite 287 [1.08] and a 300 [1.14], to see how they'd compare to the Holley 350. Maybe even a 351 [1.21] or 356 [1.23], but I'm guessing they might be to big? NOTE: the venturi size is in [parenthesis].
Carb - CFM - Dizzy - Max HP - Max TQ - HP/CFM - Gain
Autolite 1V - 180 - LOM - 62 @ 3900 - 93 @ 2900 - 0.34 - Baseline
Weber 2V - 300 - LOM - 70 @ 4300 - 94 @ 3350 - 0.23 - Baseline
Weber 2V - 300 - DUI - 85 @ 4900 - 105 @ 3300- 0.28 - 27 %
Autolite 2V - 240 - DUI - 83 @ 4950 - 105 @ 3400 - 0.35 - 25 %
Autolite 2V - 245 - DUI - 84 @ 4900 - 105 @ 3300 - 0.34 - 26 %
Holley 2V - 350 - DUI - 87 @ 4800 - 106 @ 3200 - 0.25 - 29 %
As for the drivability with the DUI, here are his comments after the drive home.
NEXT UP: Testing the modified log head, hopefully next week.
The log head had 180/150 oversized valves installed, plus a little port work in the intake runners and a basic cleanup in the bowls. While the test won't be apples to apples, it will still give us a good comparison. I figure most guys who pull a head and modify it, are probably going to install bigger valves. Why go to the trouble of modifying the intake, if your not going to make to most of it?
Again, the idea is to test what most are doing to their motors, rather than strictly apples to apples. Why go thru all the extra labor and expense to pull the head twice, plus the extra dyno time to retest. I'm betting more guys will install oversized valves, rather than just modifying the intake and leaving it at that. Sure it would be nice to know; unfortunately I have a budget and need to make the most of it.
We weren't able to test the DSII today as planned, as we couldn't find one. We checked with three different chains, and all three told us they no longer stock them, as they are now a special order item. That was disappointing, as I was really hoping to test the DSII vs. the DUI. Guess we'll just have to do it another day. As a result, I'm going to see if I can get the DSII and keep them in stock.
We wanted to test the high ratio rockers too, but that also had to be put off for another day, as I am currently out of ball and cup pushrods for the 200ci. I've had them on order for several weeks, but getting parts from this supplier is difficult, to say the least. I keep making phone calls, and had my fingers crossed, but no luck. Hopefully I'll get them next week.
We did test the DUI however. Again, this was on a 200ci with a fresh rebuild, a 264-112 cam, and headers. Keep in mind; the baseline Weber had no provisions for vacuum advance. Using the Weber baseline with the stock dizzy, we gained 15HP & 13 lbs of torque after installing the DUI. The Weber/DUI combo, over the 1100 and stock dizzy, gained 23HP and 10 lbs of torque, while the Holley/DUI combo netted 25HP and 12 lbs of torque. That's a 29% increase in HP.
One problem I noticed, is that the motor doesn't make much power down low, but takes off once it gets past 2500rpm. My guess is that the cam is retarded, maybe as much as 6-8 degrees, as it wasn't degreed when it was installed. Even if the cam is ground spot on, Clay Smith recommends installing them 4 degrees advanced (their cams are ground straight up), therefore it's at least 4 degrees retarded. I'm guessing even more based on how the motor was performing, as it should make a lot more bottom end power.
However he is going to replace the damper soon, as it has slipped considerably. At that time, he plans to degree the cam. Once that's done, I'd like to take it back for another go around. If I'm right, it will make a huge difference.
EDIT: I had to take a break for dinner. LOL
As for the carb test, we did the baseline last week with the stock 1100 carb. This morning, the Weber was already installed when we got there, so we were able to get right to it. We did our first run with the Weber, then pulled the stock dizzy and installed the DUI. After a run with the Weber and the DUI, we installed the Autolite 240cfm and did two more pulls. Next we installed the Holley 350cfm and did another run. Our finally pass was with an Autolite 245cfm, which I decided to bring along.
Remember, both Autolites were used carbs purchased at a swap meet earlier this summer, so we had no idea of their condition, or if they would even run. To our surprise both worked fine, however it was obvious that the 245cfm needed a rebuild. It also needed to be re-jetted as it was quite lean, however we didn't take time to re-jet as it was lunchtime and the guys were ready. Therefore we decided to call it a day. We got the info we were after using the first three carbs, so the last run didn't really matter.
SUMMARY: The progressive Weber made the least power, while the Holley 350 made the most. The Autolite 240 [1.01] & 245 [1.02] were in between, with the 245 making more, even in its poor condition. However, all the runs were within 2 HP and 3 lbs of torque. If I can afford it, I'd like to try an Autolite 287 [1.08] and a 300 [1.14], to see how they'd compare to the Holley 350. Maybe even a 351 [1.21] or 356 [1.23], but I'm guessing they might be to big? NOTE: the venturi size is in [parenthesis].
Carb - CFM - Dizzy - Max HP - Max TQ - HP/CFM - Gain
Autolite 1V - 180 - LOM - 62 @ 3900 - 93 @ 2900 - 0.34 - Baseline
Weber 2V - 300 - LOM - 70 @ 4300 - 94 @ 3350 - 0.23 - Baseline
Weber 2V - 300 - DUI - 85 @ 4900 - 105 @ 3300- 0.28 - 27 %
Autolite 2V - 240 - DUI - 83 @ 4950 - 105 @ 3400 - 0.35 - 25 %
Autolite 2V - 245 - DUI - 84 @ 4900 - 105 @ 3300 - 0.34 - 26 %
Holley 2V - 350 - DUI - 87 @ 4800 - 106 @ 3200 - 0.25 - 29 %
As for the drivability with the DUI, here are his comments after the drive home.
NEXT UP: Testing the modified log head, hopefully next week.
The log head had 180/150 oversized valves installed, plus a little port work in the intake runners and a basic cleanup in the bowls. While the test won't be apples to apples, it will still give us a good comparison. I figure most guys who pull a head and modify it, are probably going to install bigger valves. Why go to the trouble of modifying the intake, if your not going to make to most of it?
Again, the idea is to test what most are doing to their motors, rather than strictly apples to apples. Why go thru all the extra labor and expense to pull the head twice, plus the extra dyno time to retest. I'm betting more guys will install oversized valves, rather than just modifying the intake and leaving it at that. Sure it would be nice to know; unfortunately I have a budget and need to make the most of it.
With only 200 C.I., thats a huge gain in horsepower just between distributors, I guess there goes a few more bucks out of my pocket, while I believe the results I find it hard to understand it can be so much, 13 horses is almost half what it takes to drive an M90 or close their of. I actually hate it since I have a pertronix 2 and their 60000 low ohm coil , rebuilt dist. and pricey brass terminal cap already in hand. But what good info!!!!
Kinda reinforces the point (no pun intended) that ignition should be one of the first mods you make.
a couple of additional notes:
- I don't understand why the Holley/Weber made less horsepower than the stock and very sick carb. I expected a modest increase like the same carb did on Gene's car. The stock carb was very lean throughout the whole RPM range on the baseline run. The A/F mixture was good across the RPM range on the HW and we checked beforehand to make sure we were achieving WOT with my makeshift linkage.
- I failed to mention the much improved idle quality with the DUI. With the stock ignition it acted as if it was rich/loading up. With the DUI the idle is much smoother in neutral and it will now idle in gear... pretty much.
- I don't understand why the Holley/Weber made less horsepower than the stock and very sick carb. I expected a modest increase like the same carb did on Gene's car. The stock carb was very lean throughout the whole RPM range on the baseline run. The A/F mixture was good across the RPM range on the HW and we checked beforehand to make sure we were achieving WOT with my makeshift linkage.
- I failed to mention the much improved idle quality with the DUI. With the stock ignition it acted as if it was rich/loading up. With the DUI the idle is much smoother in neutral and it will now idle in gear... pretty much.
Broncitis":59ygzz0w said:
I don't know for sure if the DUI is just better, or if the Petronics or DSII will give you the same results. So far, I've only seen one direct comparison between the DUI and the DSII, which showed the DUI making more power. Which is why I wanted to test the DSII yesterday.
But there are other points (pun) to consider. While some people think the DUI isn't worth the extra cost over the DSII, I personally think it is. Not so much just for the performance, but for the ease of installation and maintenance, as well as the availability and low cost for replacement parts. How much does it cost to replace a bad MSD6A or Petronics, and how available are they? On the other hand, a DUI module can be purchased anywhere for less than $40 bucks. Summit carrys one for $20 bucks, which is so cheap you can actually afford to carry a spare in your glove box. That way you don't wind up calling a tow truck if you break down on the road, or live in a rural area where performance shops are non-existent.
Re: electronic ignition. David Vizard says that up to 15% of the fuel remains unburned with a conventional points ignition due to incomplete combustion or outright misfires. With an efficient, modern electronic ignition providing a big, fat, powerful and dependable spark, far more of this fuel will be consumed. There is your first and greatest gain, even if the combustion failure was only 10% or so before the new ignition. Obviously, a good ignition is essential to significant improvements through a better carb.
AzCoupe":3o9b2gs5 said:
FWIW, a GM module (which AFAIK is the same module used in the DUI) can be purchased at any parts store for ~ $20. There is really very little physical difference between the DUI and DSII, other than location of the coil. One advantage of the DSII is that rotors and caps can be easily bought at any parts store.
The GM module is what I recommend for use w/ the DSII. Using a MSD is another ballgame and offers some benefits that the DUI does not. (Multiple spark discharge, rev limiting, and capacitive discharge).
So comparing DUI to DSII + MSD is not really a fair comparison for the DUI.
It's no surprise to me that the DUI made that much more power over the points ignition.
Points style ignitions just aren't very good - plain and simple.
Something that should be mentioned here is repeatability. When we are talking about such small differences in power ( < 5 hp ) it is pretty hard to say, without a lot of testing, that the numbers are concrete.
Just because the Autolite made 94 Hp this time and the Weber made 91 doesn't mean that if you let the car cool down and ran them in the opposite order they would do the same thing again. It could just as easily reverse, based on numerous environmental variables.
What it does show is that none of these carbs is significantly better than the others (On this engine) - which is interesting but not shocking.
The DUI (or likely any other electronic ignition setup) is certainly an improvement over points.
Thanks Mike.
66 Fastback
Famous Member
What was the stock distributor? Was it a Loadamatic?
And if there are no provisions for vacuum advance on the Weber, was the distributor vac advance not hooked up at all? If so, that would explain some of the drivability issues. I don't know that it would change much on the dyno though.
Doug