Off to the dream crusher!

davec73

SCCoA Member
Well the car is ready and its off to the dream crusher this Saturday so Dave can get my car tuned so I can race it for the first time at this years shootout. Its been a long time with a lot of things to discourage me along the way, I felt like giving up and selling all of it on more than one occasion. The car has ran really well since I found the cause of a few of my issues while upgrading to the AR and I just ironed out the last known bugs today in the form of a bad IAC and a few other misc things. I will be running C10 race fuel and about 15% od on the AR without nitrous for now because I just don't feel like the motor has enough miles on it to throw another power adder at it just yet. Whatever the result as long as I walk away with a good running car I will be a happy man but as soon as I get the final numbers I will post up the dyno sheet, wish me luck!
 
Well the car is ready and its off to the dream crusher this Saturday so Dave can get my car tuned so I can race it for the first time at this years shootout. Its been a long time with a lot of things to discourage me along the way, I felt like giving up and selling all of it on more than one occasion. The car has ran really well since I found the cause of a few of my issues while upgrading to the AR and I just ironed out the last known bugs today in the form of a bad IAC and a few other misc things. I will be running C10 race fuel and about 15% od on the AR without nitrous for now because I just don't feel like the motor has enough miles on it to throw another power adder at it just yet. Whatever the result as long as I walk away with a good running car I will be a happy man but as soon as I get the final numbers I will post up the dyno sheet, wish me luck!

Good luck buddy

Ken
 
Dave,

When you say 15% OD what does that mean ? 10% jack shaft pulley and smaller than usual supercharger pulley ? What diameter blower pulley are you using ?

David
 
10% crank pulley 2.9 blower

Looking forward to hearing how it does. That is probably very close to the max rpm for the blower, depending on high high you rev the motor. Do you know what peak boost you are currently producing ?

On my 3.8 motor a 10% JS and 3.00 blower pulley made 23 pounds of boost vs. the 20 pounds I was making with a 3.25" diameter pulley. Unfortunately it pulled lower numbers on the dyno by 25 rwhp, so I switched back to the 3.25" diameter. I just figured I was spinning the blower too fast and it was consuming more HP than the extra boost was creating. It also could have been pulling timing because of excessive air temps. When using this blower on my 4.2 motor, it was necessary to use the 3.00" diameter pulley to get boost back up to 20 pounds. With the 3.25" pulley it only made 17.5 psi on the 4.2 motor.

David
 
I don't have a 3.25 pulley and it is going to cost me 180 bucks to have south florida pulley make one. I havnt seen the car get over 17 psi yet but I have rarely been over 4000 RPM. Ryan Zimmerly ran the exact OD intake TB inlet etc on his car with 0 issues so I am really out of options when it comes to altering OD at this time. The inlet for the supercharger is very large and I am excited to see what it does because my low end seems fairly decent but I will just have to waite til sat morning to find out. The one question I have is the mini cooper BBV has never been adjusted so I don't know how to adjust it or if it is closing fully.
 
I have the bigger pulley laying around....
with the small pulley and I think a 10% js i am making 23psi..might be a 5% who knowssss.. I can check if its of any use to you.
 
Dyno D day

Randy and I arrived very early this morning and got a couple hours of sleep before we headed over to SCU to meet Dave and Phil. We road tuned the car on the way over to the dyno and all was going really well so Kevin and Phil straped it in and we went to work. Pulled it to 5000 on 93 and it was mid 300s and the boost hadn't peaked. Second pull was 360 ish and the boost fell flat at 18 it never really got any higher than that! This is an AR with 10% crank pulley and a 2.9" blower pulley so we know I am definitely bleeding boost of somewhere. The weirdest event of the day was the fact that the Dyno sheets from today and last June with the MPX were nearly identical! I mean identical as in nearly exactly the same dips, rises and everything in between and that might not be so unusual if we hadn't changed the cam and completely changed the supercharger to a twin screw:eek: So I still have a couple of issues that are holding the car back and I have to get them sorted out. It still has an abnormally high amount of crank case pressure and I am bleeding boost off somewhere but I just have to find the root of the issue. The good news is the car is now very reliable and It runs very strong, one thought is that with all of the fueling issues I had in the beginning the rings have had a tough time sealing properly although it only exhibited major signs of this once today the problem still exists and it just needs driven hard for a while. Now that the car is properly tuned I plan to try to get around 5000 or so miles on it and try to eliminate all possible causes of external boost leaks. Sadly here are the best numbers it put up for the day.dynoAR_zpsd71c121c.jpg
dynoAR_zpsd95272d0.jpg
 
good job dave

You've done a helluva good job building that car of yours, great customizations, and attention to detail. You've made that thing beautifully yours. I realize things can get frustrating especially when that magic dyno number doesn't happen (personally dyno numbers don't mean ~~~~ but bragging rights) but you've come soo far to where you are now. Personally I would take a break and some time to just enjoy that great car of yours.... I'm sure she feels amazing just how she is. All my best to you and yours.
 
Must be leaking boost somewhere, because that pulley combo should easily produce 22 pounds of boost on a 3.8 motor. Glad to hear everything else went well.

David
 
Must be leaking boost somewhere, because that pulley combo should easily produce 22 pounds of boost on a 3.8 motor. Glad to hear everything else went well.

David

Besides 22# boost, what hp/torque would you expect in that example? What do you think - is 4# more liable to make another 100hp, or....?
 
Good #'s boost sounds low, belts slipping or boost leak mabe make sure your air filter is not to small and sucking shut. Since the hp#'s are close do you think it runs better with AR or MPX?
 
Besides 22# boost, what hp/torque would you expect in that example? What do you think - is 4# more liable to make another 100hp, or....?
I don't think the heads on this car flow well enough to make 480. The car should have easily made 450 or right around that mark with 21 to 22 psi holding steady and peaked at a higher number but it didn't. One thing I didn't consider is the way I have the air filter housed under the engine cover but I don't see how it could make that much difference. I think I have a boost leak at my top, BBV valve or possibly the lower intake manifold and if it is there we will find it if not ????????
 
I don't think the heads on this car flow well enough to make 480. The car should have easily made 450 or right around that mark with 21 to 22 psi holding steady and peaked at a higher number but it didn't.

Dave,
I thought that my car would have made at least 450 rwhp but only produced 383 rwhp with a spark issue so I know how you feel........:eek:
 
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