trever phillips

On the dyno the power dropped down after about 5000 rpm I think the stock cam is the issue here , I seen nothing but boost cams in this forum and its year end so the x-mas list starts.

BigBenz

iTrader: (7)

From what i see a cam will give you large power gains. If your on a stock bottom end you might not want to push that kind of power. What kind of numbers are you seeng now? A stock bottom end is good for around 500rwhp. Anyhing above your asking for problems.

trever phillips

This is 10# what do yeah thing? [IMG][/IMG]

Slowhawk

iTrader: (12)

Looks like boost drop or floating valves. We ussually recomend unpgrading the valve springs on stock Cams running boost.

Here is a graph of a small Cam,big motor,14lbs of boost. As you see peak power is very early but flatlines.That is a cam that is too small for the setup.

67Firebird455

iTrader: (27)

Wow, that really sticks out, ran out of cam. I've never seen a graph like that!

Slowhawk

iTrader: (12)

Here is a before/After on 2 graphs that show a turbo car with bad valve springs and stock Cam.This was an 04 GTO to give you an idea.

trever phillips

I never thought of that, that makes sents thank you for pointing this out.

67Firebird455

iTrader: (27)

Oh crap, talk about defining it. Gets all crappy jagged too. Can't control the valve under boost!

trever phillips

Ha ha nitrous cars are kicking my butt, i want my car too pull hard till redline and i can feel the power drop off at upper r's

BigBenz

iTrader: (7)

maybe turn down the boost a little see what you get.

trever phillips

We started there lowest setting was 7# and same thing, power tappered down just the same

hellbents10

iTrader: (10)

800hp is easily attianable on a stock cam. Just ask Chris. It depends where power comes in and where you want your powerband.

BoostnTBSS

iTrader: (-1)

what size is you ex housing? and wast gate?

trever phillips

Well the turbo is a turbonetics t-76mps that's all i know I sent a pm to Jose at forced inductions for a compressor map and tail 38mm w/g Oh and T-4 flange on the turbo

MIGHTYMOUSE

iTrader: (59)

maybe its being crazy overfueled past 5k?

just a thought does your controller have overboost shutdown? did the gauge stay at 10# the entire pull?

trever phillips

No over boost shutdown, just a manual boost controller and the gauge stays there the first pull we did it was mid 10's a/f and you could hear it breaking up so we took fuel out of it, we did like 13 pulls starting at 7# up to 13# and all pulls power tapered off. I'm having the dyno place e mail me the pulls I have then on paper somewhere?

Slowhawk

iTrader: (12)

Did you add timing at the end of the run? I would figure 12-14 degree's at peak torque and 18 or so degree's at 5500+

trever phillips

Under boost (4000 rpms) timing drops from 23* to 13* g/cly .32 @ 23* and 13* @.56 g/cly and timing stays there till red-line I just did a data log just to make sure and at 13* on the scale with hp tunners on the knock side at .60 and 4000 rpm 1* of knock till .84 at 6000 so 4000 - 6000 timing is 13-12*

So what should I do drop boost and all some timing up there

Thanks for the help

jsmcortina

What springs do you usually fit?

James

trever phillips

Oh shoot the log i just did was a pull in 3 and 4th gear and 3rd gear i got the knock at 4000 to 6000rpms (tire spin) and forth gear 4000 to 6000 rpms no knock! What should I do, Ha ha 3rd gear roll ons 4200rpms (70mph) when tires are cold it spins the tires 1.5* of knock then it fades out. What is wrong with us, boost is worse then crack always want more