corvette_uae1

hi guys plzzz help me

im really disappointed from my setup i got a cr8 chevy engine with harrop supercharge 11 psi with 408ci and prc heads stage 2.5 with kooks minifold and magna flow catback

the car is really kicks untill it reaches 4200 rpm then something holds it i tuned the car twice with 2 well known tuners and the same issue

first they told me the stock ls2 heads hold the power so i changed it and the same thing the power holds on 4200 so i dont think the heads are the problem

i checked the whole water piping and vacum everysingle thing

the same problem !!

check the dyno


some tells me the supercharger belt is slipping and some says the supercharger is damaged but no sound of bearings and if its damaged the car wont run great and burn out untill 4200 rpm

the engine sounds good no sound and run smooth !!

The electric water pump is pumping fluid fine no leak !

the fuel is great both tuners said that !!




plzzzz help me guys !!! what do u think is the problem!!!

JAX04

iTrader: (17)

what pulleys do you have, and how many ribs is the belt??

trans2000am

iTrader: (49)

im sure you have upgraded valve springs right? check valve train

corvette_uae1

exactly this is the same belt jax04



yes trans2000 am i did order a set of heads from texas speed with double springs !! so i dont think thier is a valve float

bondosgto

jax ment he size and rib count of the belt and pulley from the crank. what injectors and fuel system are you running?

AgFormula02

iTrader: (13)

Is the boost constant? Fuel pressure good? Air temps?
My 4.8 was making 400 at 7 psi with stock heads.
If the belt is slipping, is there belt dust ?

mjcotroneo

iTrader: (12)

umm how sure are you that you have a 408? if the tune is good, fuel is good, no slipping belt, valvetrain is fine, and heads are good i would say check to make sure you got a 408 dude. the 408 should have made more on motor.

JAX04

iTrader: (17)

Ok, so you have a COG setup, interesting, so there wouldnt be any belt slip then. What about valves springs as mentioned above??

EDIT: saw your post about double springs. hmmmm

automatic or clutch car??

JHR Performance

Looks like the cog is setup on the rear. OP, what do you have on the front of the blower? The standard Harrop 8 rib or is it cog too?


Zach

old motorhead

iTrader: (10)

Which blower do you have? I know the later ones are TVS units. They make a 1900. Maybe a 2300 too. As mentioned above, if you're indeed having belt slip issues, the slip isn't coming from the pictured area. I'm assuming it's a front drive and those pictures are of the rear of the blower. Do you have a graph of the boost curve?

JAX04

iTrader: (17)

Fudge me, Doh, i new that was the rear, my bad, didnt even realize i was looking at that.

yes, what belt do you have on the front, as previously asked.

also, the harrop and tvs are different, are they not??

old motorhead

iTrader: (10)

It's my understanding that the newer Harrop blowers use the TVS guts. If that's not the case, someone please correct me. Magnuson, GM, Edelbrock, and Harrop all use TVS.

JAX04

iTrader: (17)

i was referring to the setup its self, im used to looking at the maggie tvs units where the drive gears or rear pulleys are side by side, this harrop in over and under, thats why i mistook this picture.

and i dont know about the rotors.

killernoodle

Is the car getting knock and pulling crazy amounts of timing?

shift_grind

Do you have cats?

might have melted them, how much boost SHOULD you be running? 11 sounds a little high in a 408 with heads, but i don't know what rpm your spinning at.

corvette_uae1

timing is good cuz we try to change it the same problem

catback is good i got magna flow catback !

8 rib belt on the car so no sliping !
im getting sick from my car !

i checked all the pipings the cooler and the vacum hoses !

dam im gonna sell this car

pm2630

Simple fix - just put a .050 shorter push rod in your motor. That will fix everything. Your lifter is working at the very bottom and is collapsing @ mid range. If you shorten the push rod .050 that would put your lifter back in the middle of the working mechanism and you will be just fine. Sorry you had the problem. When someone comes out with adjustable rockers, we won't have this problem to do all the measuring but believe me this will fix your problem. It's not valve springs or float or fuel or pump or anything else. Just do like I suggested and be happy and satisfied that you have your problem fixed. I'm just a 68 year old man trying to help as I was helped when I was young.
pm 2630

lunati397

also what cam is in that motor

Hank Peabody

iTrader: (2)

Sounds like some legit advice!!!

Mr.Big

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