UsmcMustang

allright guys let me list off my mods and then i tell ya my rwhp and what the cause of such a low number could be


- 5.1 l low compression dish pistons - 13.55
- livernois stage 3 heads
- bbk longtube headers
- high flow cats
- outlaw flowmaster axle back
- saleen stage 4 cold air
- comp cams stage 2 nsr
- 47 lbs injectors
- stock intake
- stock throttle body
- livernois lock outs
- 4:10 gears


allright i got it dynoed it made 321 rwhp , which i think is kinda low , i was wondering if it could be because i have a low compression engine ( saving for kenne bell supercharger 2.8 l and a t - 56 magnum )

i believe that static compression is 9.04 , i could be wrong


if that is the cause anyway to increase the compression without using a supercharger since that one will be out of my reach for awhile since im restoring a 67 pontiac tempest at the moment

again any input is appreciated

UsmcMustang

ps

i had it dynoed back in 2011 minus the injectors and the heads and it made 360 rwhp on a dyno dynamics

the recently one used is a dynojet

i understand you have to take dyno numbers with a grain of salt , on the good side last time it dynoed at 298 and it gained some good amount

JCON

Confused as to what pistons you actually have but yes, running lower compression on a non-boosted car will lower your power. Without heads and pistons you should put down 330-340rwhp. With heads, you should be pushing around 350-360rwhp depending on porting. Nothing really you can do except change your internals again.

danzcool

Well, yes, lower compression lowers horsepower until you boost it. It looks like a built engine, so have you upped the redline yet? I'd guess that upping it to 7k and changing the throttle body would help a bit.

PNYXPRESS

unless Im missing something, it looks like youve done alot to increase airflow thru and out of the engine,but nothing to increase airflow INTO the engine.

headwork, LTs, and cats cant flow air that isnt coming in.

ghunt

This is kinda unrelated but I'm curious as to why you got ported heads and then used NSR cams?

On that topic, I was looking at Comp's own literature and they show that the Stage 2 NSR cams are down on power to the stock cams clear up to 5000 RPM. Might also be an issue.

Also I really doubt the stock throttle body and intake are a restriction on a non-sc engine.

UsmcMustang

before i got the new heads i had the nsr cams , since i want to go with a blower once i get a new tranny i didnt want to spend money on new cams which i need to replace later anyways , same with the intake and throttle body , the kb swaps all that stuff out

i got probe pistons i know they are dish pistons with - 13.55 cc

Pnyxpress , i just saw what you meant , i figured the supercharger would be the increase and air flow , but i see what you mean , i was hoping the bigger heads and bigger injectors would help increase compression ratio since they can move in more air and fuel

again thank you guys for the input

Nuke

No mention of who's doing the tuning...

AMWill

I think you're right where you should be with a manual, stock TB, stock intake, and current mods. 9.04:1 compression is pretty low for a N/A engine (until it's boosted at least). With aftermarket camshafts, you're going to have more valve overlap causing an even lower than stock dynamic compression. Regardless how free flowing the top end is, I wouldn't expect big power with that compression. Plus, as I mentioned above, having high flowing cylinder heads and aftermarket cams, you're more limited with the factory intake and TB too.

Personally, I wouldn't worry one bit about the power the engine has made so far. Once you throw the 2.8L KB on there, you'll really see what the engine is designed for. Trust me!

Shane