3.4 Boost Question

ITSTOCK

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If you have the crusher and head studs, I was running 32 pounds on stock longblock+studs and there is a SUBTANTIAL difference in feeling between 27#'s and 32. I definitely wouldn't hesitate to up the boost.

Based on your levels, do you have cams? I would think that you should be closer to 28/30 as is, on a stock long block. 3.25 upper only was 27#'s on the stock long block with my car, 3.0 upper only was 32.
 

Paul Delapenha

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My bottom end is built with ported heads and cams. I was trying to find out the sweet spot on the 3.4 someone told me 27-28 just wanted to hear what others are saying
 

Paul Delapenha

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If you have the crusher and head studs, I was running 32 pounds on stock longblock+studs and there is a SUBTANTIAL difference in feeling between 27#'s and 32. I definitely wouldn't hesitate to up the boost.

Based on your levels, do you have cams? I would think that you should be closer to 28/30 as is, on a stock long block. 3.25 upper only was 27#'s on the stock long block with my car, 3.0 upper only was 32.
 

ITSTOCK

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How much power were you making on 32lbs? What did you do to support the crank and snout issues?

It was never dynoed, went 9.2@146 full weight at 27#'s, and I could only do roll racing with the smaller 3.0 pulley as I kept shearing apart my stock lower crank support on launch at the track.

The blower RPM is still in it's efficiency range if you put the smaller upper on it at 21krpm.


The new engine that I'm running now with the 3.0 whipple, I have the snout mod, keyed, and j2 crank support.
 

Paul Delapenha

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It was never dynoed, went 9.2@146 full weight at 27#'s, and I could only do roll racing with the smaller 3.0 pulley as I kept shearing apart my stock lower crank support on launch at the track.

The blower RPM is still in it's efficiency range if you put the smaller upper on it at 21krpm.


The new engine that I'm running now with the 3.0 whipple, I have the snout mod, keyed, and j2 crank support.
So if I do only roll racing my crank should be ok?
 

ITSTOCK

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So if I do only roll racing my crank should be ok?

The violence occurs during sudden acceleration and deceleration of the components, so launch and shifting really. If you have absolutely nothing done to the crank, I would consider going back to a stock lower caged setup (with a smaller upper) and using that as a weak point instead of the crank itself.
 

Wings65288

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Im at 28 to 29 pounds and car feels great (crusher setup on a built Teksid with 9.5:1 Gibtecs). Mine is a caged 4# lower with a 3.25 upper. My best is a 10.29 @ 141 and this was on 3.5 upper / 4# lower (26 pounds) with a lot of bounce on the launch. Anyway I've upped the boost and have fixed the hop, im putting ARH long tubes on and shooting for a 9. SHOULD be able to get it. 9.2 @ 146 is awesome ITSTOCK, great pass. What was your 60 foot? You auto or T56?
 

ITSTOCK

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Im at 28 to 29 pounds and car feels great (crusher setup on a built Teksid with 9.5:1 Gibtecs). Mine is a caged 4# lower with a 3.25 upper. My best is a 10.29 @ 141 and this was on 3.5 upper / 4# lower (26 pounds) with a lot of bounce on the launch. Anyway I've upped the boost and have fixed the hop, im putting ARH long tubes on and shooting for a 9. SHOULD be able to get it. 9.2 @ 146 is awesome ITSTOCK, great pass. What was your 60 foot? You auto or T56?

I'm auto (TH400), 1.31 60' on that pass.
 

Paul Delapenha

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Im at 28 to 29 pounds and car feels great (crusher setup on a built Teksid with 9.5:1 Gibtecs). Mine is a caged 4# lower with a 3.25 upper. My best is a 10.29 @ 141 and this was on 3.5 upper / 4# lower (26 pounds) with a lot of bounce on the launch. Anyway I've upped the boost and have fixed the hop, im putting ARH long tubes on and shooting for a 9. SHOULD be able to get it. 9.2 @ 146 is awesome ITSTOCK, great pass. What was your 60 foot? You auto or T56?
I'm t56 magnum. I've never taken the car to the track, and I honestly have no desire. I'm setting the car up for roll racing. I plan on entering 1/3 and half mile events. How much power did you make on 28lbs? You and I have similar build and combo. My car made 900/830 on 26lbs. Would have made more but I was running out of injector. Going back for another tune in July and that's why I was trying to see if I could turn up the boost.
 

Wings65288

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You know I've never got it dyno'd so i have no idea. After i get long tubes on i may dyno it. Like i said @ 26 pounds i was trapping 140 - 141. So now that im at 28 to 29 pounds hopefully i can trap around 143+ once i get out there.

Edit: I forgot actually made a quick hot lap pass on the new boost setup with lots of spin in 1st on a non prepped track. 10.5 @ 138 (no long tubes).
 
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Wings65288

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The 3.4 setup had a stock lower.

My new built engine gen 5 3.0 has a 4# lower and 3.0 upper, but I'm having trouble keeping the belt on.
interesting you have any ideas why? Have u tried sticking a washer behind the alternator pulley?
 

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