I have a 91 350 in my 88 iroc. It ran a 14.2 @98 mph stock a month ago. Last night i ran a 14.8 @91mph after adding a TPIS miniram also I added a crane flat tappet cam part number 100052 from crane. My fuel pressure was set to 55. Why is my car slower than it was when it was stock. It seems i lost alot of my low end torque.Please help me understand.

Thanks,
Mark

 

Post specs on cam please.

 

here is the link with the specs of the cam.
http://www.cranecams.com/index.php?s...52&lvl=2&prt=5

crane energizer 272/272 with .454/.454 lift and a 110 lob sep

 

That cam is not a roller cam. Don't you have a roller engine?

It's also a single pattern, 110 LSA cam and not designed to be used on a computer controlled engine.

Also, why in the world do you have your fuel set to 55 psi? You're probably running very rich.

 

I had it done at a shop . They put new lifters in with that cam.Should i put the old cam back in.If so does the motor have to be pulled out.what should my FP be set at for that miniram.
Thanks

 

Sounds like you have a total mismatch of parts. You didn't list any head work, injector sizing, PROM tuning, gearing, or torque converter stall so I will assume those are all stock....and so there lies your problem.

I think TPIS did a great job advertising its Miniram to give you 95 horses over stock and nothing else. What they don't tell you is you gain that in the upper rpm range of a stock L98 where it no longer makes usable power. On a dyno printout out that looks impressive but in the real world on a drag strip you will not go any faster as you've experienced first hand.

Miniram is an awesome intake but you will need more cam, more head flow, more stall, more gearing, more injector to make it fly.

 

That cam is kinda funky, it's not that hot, and it's flat tappet. Why on earth would you use that cam? Not a good match.

I'd give the shop a piece of my mind for suggesting/using that one. Then i'd go grab my roller lifters back, and get a reasonable roller cam, split pattern, and try that out. It woulda cost about the same from the start.

 

I think your right, I'm going to put a roller back in. do i have to drop the motor in an 88 iroc to swap the cam. I not taking her back to that shop.

 

You can change the cam with the engine in the car, but it's a pain....

Remove the intake manifold, rockers/push rods/ lifters, radiator, water pump, timing cover/chain.

In fact it's so much work that you may as well remove the heads and either replace them or have them ported.

And set the fuel pressure to something closer to stock, like 46 psi.