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Twin-charged Bonneville Update

Old Oct 3, 2009 | 08:25 PM
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Default Twin-charged Bonneville Update

I finally put some miles on it and worked out all the kinks, slow turbo oil return, leaking op gasket, crack prone rear header... I bought a rear turbo Powerlog from ZZP and modified the outlet to fit my existing turbo uppipe.

I took it to the dyno last night and made some good runs. But I kept hitting a wall at 5500rpm. I didn;t have my scanner with me at the dyno, so it was not until today I found out the knock ret attack rate was still set to stock value. It was pulling 12deg at 5500 and levelled of at what the scanner showed was 0deg timing, but I know was about -4deg atdc.

Still, it made 376whp at 5500 with a combined 15psi (turbo making 7psi max). I drove the car today before making changes and you could definately feel it fall flat at 5500. I made a few changes, went back on the road and WOW it pulls hard all the way to the MSD-induced 6250rpm rev limit. With only .5-1.3deg KR. That'* with only water in the intercoolers (twins). I have not installed the ice tank in the trunk yet.

Here'* the dyno graph. You can see it hit the wall. Also, you can extrapolate using the hp curve and see if you come up with what it is probably making currently. (390-400whp is my guess.)

There is alot more in it at this state of tune. I am running 11.5:1 a/f and as I said, ambient air temp/water temp in both i/c'*. (which was about 72deg last night) It'* running 12.5deg timing, too which is very conservative for this setup.
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Old Oct 3, 2009 | 08:32 PM
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Wow, now that is some crazy power.
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Old Oct 3, 2009 | 09:03 PM
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Thanks!

On a lighter note, I was thinking of installing a set of these heat-extractors in my hood, they are from a '90 McLaren Turbo GP. What do you think? I figure it'* only fitting since I run a set of the TGP 16x8 gold wheels on my Bonne with 245/60'*.
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Old Oct 3, 2009 | 09:19 PM
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Great numbers there ! And by using a twisted scheme of delivering boost. Incredible job Jeff.
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Old Oct 3, 2009 | 09:27 PM
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I had to build a totally new fuel system. I don;t have any pics yet, but it is consists of a replacement Walbro 255 (the first one would not make over 50psi), a Mallory adj fpr, -8 feed tee'd into the fuel logs (modified L32 stock rails), all -8 braided hose and Earls fittings. I set the base fp at 50psi for now. I'll take some new pics Sunday and post them.

My stated goal from the beginning (over three years ago...) is 500whp. I should be able to do that with about 12psi turbo and still be 20psi or less total combined boost.
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Old Oct 3, 2009 | 09:30 PM
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You intend to push 500whp onto a 4t65?
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Old Oct 3, 2009 | 09:31 PM
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Old pic for those who have never seen it.

Not too much has changed visually.

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Old Oct 3, 2009 | 09:35 PM
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Originally Posted by GXP Venom
You intend to push 500whp onto a 4t65?
Nah, see the original thread from 3-1/2 years ago. The title says it all

https://www.gmforum.com/t229424/
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Old Oct 3, 2009 | 09:53 PM
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LOL! A little red faced here. I was a noob at the time and totally forgot that thread. My hats off to you. Supreme ingenuity and workmanship. Why aren't you a gearhead? Then or now???
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Old Oct 3, 2009 | 10:07 PM
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I don;t know why. How does one become "GEARHEAD"?
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