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 Post subject: Head Swap Results
 Post Posted: Tue Mar 23, 2010 5:35 am 
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Hello All,

I have some results regarding the AIRWOLF cylinder heads. I have been very impressed with the results and workmanship of these cylinders heads. The only changes made in the dyno testing was the cylinder heads. The cylinder heads combustion chamber was a tad smaller then my current heads. So this netted an increase of approximately .25 in compression.
This is the engine combo

Dart block
4.155 bore
3.75 stroke
JE 13 CC dome pistons
Super vic intake modified by speier racing heads
Race demon Carb
Jones cam 262/266 at .050 680/640 lift on a 110

AFR heads were previously reworked by speier racing heads. This work netted a gain of .2 in the 1/8 mile with no other changes.

Also the headers used on the dyno were a set of sprint car headers. They were two inch primaries with 3.5 collectors. The primary tubes were in the 35-40 inch range. Unfortunitly I was unable to use my headers for these test because they would not clear the dyno stand. Per Pipemax, the headers used were not the optimal heads and I feel that some power was not realized on the dyno. The headers I have in the car are right what pipe max calls for.

I made a couple passes last saturday. Car ran 6.70 at 102.5 in 2500 corrected altitude. I then pulled the motor and conducted the following:

First the engine was dyno in its current configuration. We tried different timing settings and it showed to like 35 degrees. We did not change anything on the carb as egts and o2 showed that it was on.

Then the head swap was conducted. I had to get shorter pushrods to correct the rocker arm geometry

We made the first few pulls and the engine was down on power. My dyno operator felt is was the powervalves and wanted to square up/richen the jetting and remove the powervalves. We did this with no improvement. Well it turned out that we hadn't properly adjusted the throttle linkage and we were not getting WOT. Once we corrected that, the Airwolf heads started to shine.

Immediately we noticed that the peak power had move from 6700 to 7000. Furthermore, engine was now making 40 more uncorrect hp at 7000. We tried different timing, and jetting. Ended up with the best results at 80 squared, with 33 degrees of timing before I ran out of fuel to continue testing. I still think it is on the rich side, and will want the original jetting that I had in there.

Below are the dyno results.



First night out with the car, it went 6.50@104.7 with a 1.44 sixty off the footbrake leaving at 2600 rpms. Air was at 2600 corrected altitude. Previous best at the track was at 1000 foot corrected altitude. Previuoscar best was a 6.42at 105 in San antoinio.

I also feel there is more in it, I forgot to bring the cable to reprogram my ignition box to change the shift point. There for these new best ets are shifting at 7000. Shifting at 7400-7500 would further take advantage of the heads. I believe there is probably another .05 in it. I will find out next weekend. I could really feel it start pulling about 6500.

I calculate the heads were go for a solid 40-50 hp over the worked AFR heads based on et.

As Chad and I discussed before, my previous limitation was the on power was the cylinder head.


Please let me know what you think or if you have any questions.

As I stated before, the workmanship on these heads is awesome, and the customer service is second to none. As I expected no less from chad, these heads have surpassed my expectation of them. At this point I have no plans to change any parts but tune on what I have.

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1/8   6.15@110 NEW BEST 27 Nov 11
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 Post subject: Re: Head Swap Results
 Post Posted: Tue Mar 23, 2010 5:46 am 
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Sorry Here are the dyno sheets. My computer was acting weird on the first post.

Image

Image

Image

After the best runs in the previous post, Looking through the logs, I noticed some an issue. My Egts were all over the place from cylinder to cylinder and I monitor vacuum on my logger. I noticed that the vacuum being pulled was different and droppings. Well it turns out it had some vacuum leaks. There was also so port alignment issues and the intake needed to be milled for proper alignment. The angles also had to be corrected on the intake. The issue was with the intake manifold and had nothing to do with the heads.

I went to another track on sunday. The track altitude was a 1000 foot higher then the abilene track so I wasn't setting any et records. But the car ran just under 2 tenths and 2 mph faster in the 1/8 and 3.5 tenths and 4 mph faster in the quarter. The egts were all now within 100 degrees going down the track so I was very happy with that. Correcting the vaccum leak turned the engine to the rich side of things. I didn't make any carb changes because I was competing. Car was deadly all day and took me to my first win of the seasons.


Bill

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 Post subject: Re: Head Swap Results
 Post Posted: Thu Mar 25, 2010 9:59 pm 
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I was just wondering why such a high correction factor?

I hope this isn't taken wrong, but unless the car weighs 4000+ lbs, the et doesn't support 700+ HP.

700HP should pull a 3000lb car down into the 5s 1/8 mile, in decent air.

It does look like you gained some HP, and moved peak power up in the rpm range.
Both are good, as long as you can run the engine at the rpm required for lowest et.

What stall speed are you running.

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 Post subject: Re: Head Swap Results
 Post Posted: Fri Mar 26, 2010 6:24 am 
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Hello Randy,

Even in ideal conditions, I don't think the engine will make that much. Part of the reason why the correction factor is so high is because of the altitude of the dyno. Dyno sits right at 2000 feet. I like to look at the raw numbers. I think corrected, it is probably in the 660-670 range. I find it interesting that the dyno showed 20 hp gain at peaks, but the car showed 2 tenths, which most calcs I plug that into is 40-50 hp. i think the ET supports the uncorrect numbers.

The flash stall on launch is about 5400 and fallback is 5900. I think it is on the tight side which is costing a little et.

Thanks

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 Post subject: Re: Head Swap Results
 Post Posted: Sat Mar 27, 2010 8:34 pm 
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Glad your back from your "vacation", Bill!

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 8:34 am 
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Thanks man, It is good to be back.

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 9:41 am 
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Bill, in the post above you mentioned that the "flash" was at 5400 and falls back to 5900? Did you do a type "O" on that 5400 number?


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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 9:45 am 
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Nope, that is correct, I think I need more flash to get this thing off the line better.

I can send you the logs if you like.

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 10:06 am 
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Nope, no log necessary. Was just wondering how it could "fall back" to 5900 from a 5400 flash?

I'll have to double check my logs but if memory serves at the release of the transbrake at 5200 my engine will flash to around 6200 then fall back to around 5900 once the car starts moving. Just wondering why you have that "inversion".

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 10:17 am 
 
Bills "true" stall is 5900 rpm. The tranmission will effect the starting line flash stall speed. Input shaft hole diameter, line pressure, are just a few. Back in the day we built our PG's with an external block that would allow you to change flash stall speed 600 rpms. However, it would always fall back to the same stall speed at shift. It was a crutch for not changing out to the proper converter.

Bill could use a smaller feed hole to the pump and find his missing stall flash.


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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 10:36 am 
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I launch my car on launches at 2700 rpms, immediately hits 5400 rpms, then proceeds up to 7000 which is the shift rpm. Then falls back to 5900 on the shift. I think it would benfit for a little more flash stall.

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 11:29 am 
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fourtenposi wrote:
Then falls back to 5900 on the shift.


OK so that explains it. I missed the "shift" part of all this.

Along that same line, I've got another converter sitting in the floor right now that I bought to do the same thing you are looking to do. I had that one setup with 500RPM more stall than the one I'm running now. If you ever looked at a graph from Scott's car, his converter is WAY softer at the shift than mine is and I'm moving in that direction also.

As Randy355 says, loose = fast and I proved that to myself with that way loose converter that was in the Studebaker with the POS engine two years ago.

Oh, and welcome home!!! ;-)

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 11:54 am 
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I found some interesting things with my car. When I had the 4.10 gears in there the converter was about 300 rpms looser. I put the 4.56 gears in there, the converter flash tightened up the 300 rpms, The the car seems more smoother on launch. With the 4.10 gears, it felt more violent vs the 4.56. The 4.56 gears seem slower with the old heads but more consistant. I think the converter flash was too tight which made it a tic slower. Now the new heads seem to love the 4.56 gears. Also with the 4.10 gears, it would hang on the converter for about 2-3 seconds before it would build rpm. Where the 4.56 gears, it hits 5400 and starts to climb.

I have a second converter, I think I am going to send in to get it loosened up compared to my current converter.

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 Post subject: Re: Head Swap Results
 Post Posted: Sun Mar 28, 2010 2:15 pm 
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There's a couple of things to note here. Yup, changing gear will change the converter. Changes in car weight will also change how the converter acts, ie, lighter car will tighten up the converter and heavier car will do the opposite. I've had the privilege of owning both door cars and dragsters and this has proven true with the experiences I've had. Going to a lower gear amounts to the same as taking weight off the car as it makes it easier for the engine to turn the driveshaft.

So your experience with gear shows the same thing mine does with both gear and weight differences.

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