My friend took his car to get a fast intake and tb, headers y pipe cats and 1.8 rockers. has no low end power. Anyone know what could be worng???

 

78mm fast intake and tb

 

more details needed. Other mods, motor set up, size of the TB used etc

 

all stock before it went in o ya slp LM and lid. on a mustang dyno it was 289 HP 312 before it went in.

 

have you dynoed since?

a normal check of vacuum leaks, TB opening all the way, correct TPS range etc etc. but without a dyno to see what happend you don't really know whats going on. It could just be the larger runner volume and TB shifting the power farther up the RPM band..

 

probably cause it needs a freakin cam to help move all that air... why the hell would you put a fast intake and throttle body on a car with a stock camshaft..

 

Longtubes and bigger intake are going to take away some of the low end grunt.

 

A fairly common problem with the FAST TB's. This should definitely be checked.

 

yeah, I am not at all a fan of throwing larger intake components on a stock ish motor. I can't even begin to count the number of LT1 people that throw a 58MM on and complain about loosing power. The same relationship is present here. The factory designed the Stock TB to work well with the stock displacement, cam lift etc etc. It gives you enough high end power but also is small enough to maintain flow velocity. When you upset this balance you will see the power band move up, a lot of times into an un useable RPM where you will never take advantage of it for long enough to make good power.

Since it's already done, make sure that everything is working correctly such as your TPS sweep and Throttle blade angles. Once you know that the system is working correctly dyno. you will probably see that you gained a couple of peak HP but that your average HP has either stayed the same or actually lowered. If you want to get any of that back you need to do some other things. free flowing exhaust, bigger cam etc etc etc will all help pull your average HP back into a range where you can take advantage of it.

 

does any one know would happen if you had a nonstock cam and u put 1.8 rockers??

 

dyno pic coming soon

 

Yeah, you'd make more power!

Check my signature below.

I don't know exactly what my increase would have been over the stock rockers (I'd guess ~20 rwhp), but when I swapped a set of SLP 1.85 rocker arms for a set of Crane 1.80 "Quick-Lift" roller rockers, in spite of the fact that I lost ~.010" of max valve lift due to the slightly smaller rocker arm ratio, I picked up 10 rwhp and 8 rwtq! :thumbup:

 

When the cam says "the use of 1.8 rockers is not recommended" and you put 1.8 rockers in??

 

i think my friends cam is not the stock because on mustang dyno it was 289 HP 312 TQ

 

Your question was what would happen "if you had a nonstock cam and u put 1.8 rockers." Is that what you were asking or isn't it?

If you were actually asking what would happen if you used 1.8 rockers with a cam that isn't recommended for use with them, then that's what your question should have stated.