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Pupsvette76 07-19-2012 09:30 PM

new build feels under powered
 
hey guys just got my nova road worthy however im not too happy about it while driving it for the first real drive i feel it is massively under powered for what it is...which is...
sbc 355
all forged rotating assembly 9:1 cr
stock gm heads
cam is .488 lift
summit high rise single plane intake manifold
full roller rockers 1.5 ratio
msd ecurve dizzy 15deg intial 30 total
profesional products throttle body efi 750 cfm
and a gt45 single turbo on top

the car take s little while to start i think may be due to the time it takes to build initial fuel preesure at start up
it idles at 15 inhg smoothly and it doesnt seem to miss at all on the road

Pupsvette76 07-19-2012 09:31 PM

im stumped after all the time i spent on the car im fried and need another brain to help figure it out thanks in advance for the help

68NovaSS 07-19-2012 10:06 PM

First thing you need to do is give it more total timing. Adjust your curve to have about 16 - 18 static, vac adv plugged, with 36 to 38 total, and bring it all in by around 3000 rpm.

Pupsvette76 07-20-2012 04:50 AM

currently i have it all in by 2500 is that too early i have it set for only 15 degrees in the advance sweep should i increase the amount in the advance sweep or just add more timing? there is no vacuum is just similuated vac adv since its all digital

ap72 07-20-2012 06:30 AM

Quote:

Originally Posted by Pupsvette76 (Post 1575339)
hey guys just got my nova road worthy however im not too happy about it while driving it for the first real drive i feel it is massively under powered for what it is...which is...
sbc 355
all forged rotating assembly 9:1 cr
stock gm heads
cam is .488 lift
summit high rise single plane intake manifold
full roller rockers 1.5 ratio
msd ecurve dizzy 15deg intial 30 total
profesional products throttle body efi 750 cfm
and a gt45 single turbo on top

the car take s little while to start i think may be due to the time it takes to build initial fuel preesure at start up
it idles at 15 inhg smoothly and it doesnt seem to miss at all on the road

What are you tuning it with? What heads, cam? What boost pressure? If its slapped together junk you may not be over 400hp.

ssimpala 07-20-2012 06:36 AM

Also, there's a lot more to the equation than just engine...gears, tranny, convertor, exhaust, etc. Make sure you've got all that right too.

1971BB427 07-20-2012 09:07 AM

I'd like to know more specs on the cam beyond .488 lift. What duration, and LSA? Might be the cam is too big to respond well at lower rpm's.

Pupsvette76 07-20-2012 02:34 PM

Sorry for leaving so much info out Stock heads cam is .488 lift 292 duration at .050 i believe 114 lsa boost is 5 psi gears are 4.88 on a spool 3000 stall converter in a turbo 350 the efi is self tuning

Pupsvette76 07-20-2012 05:42 PM

in order to keep the cr low i need a large cc in the head theres not too many options out there for a 76cc head or larger (76cc give me a 9:1 cr) im not sure what STOCK heads they are ...i obviously dont have as much experience as u do as im only 23 yrs old so bare with me do u have any suggestions on heads that have a larger chamber i have thought about running a thicker head gasket but dont like the idea of that i need this car to be a pump gas car due to price and availability of race fuel

Pupsvette76 07-20-2012 05:44 PM

i do have a manual boost controller that i will hook up to enable more boost

FmrStrtracer 07-20-2012 06:03 PM

How about some pics.

Did you make the turbo system, what does it consist off.(Headers, custom made manifolds, stock manifolds?)

Sounds like you expect the motor to really rpm(4.88 gears), but youve choked off the air flow with a non modified head.

There are plenty of 76cc aluminum heads available with better flow and bigger valves.

Do you know what your fuel ratio is currently?

Pupsvette76 07-20-2012 07:52 PM

a/f ratio is controlled by the efi system it idles at stoich 14.7 wot richens up to around 11.5 with a boost referenced fuel press reg rises 1 to 1 with boost not my first choise on gears but when i bought the car thats what it had have gotten around to changing them out i will prob go with a 3.55 or something close

Pupsvette76 07-21-2012 01:44 PM

I see so actually a restrictive head will cause more boost pressure even though it's not causing an increase in power

Pupsvette76 07-21-2012 02:01 PM

I would like to invest in a set of heads just can't afford them at the moment so I'm trying to work with what I got until I can buy them but I will try more time and/or more boost and see where that puts me

bigblockragtop 07-21-2012 08:23 PM

Hey F-Bird that sounds pretty cool. I can never hear detonation on my car and this sounds like a good answer. What exactly do you do with the amplifier, mount it on the motor?


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