MannyZ28

iTrader: (1)

While doing research which cam to get, I kept reading about people degreeing their cam and adjusting preload by shimming the valve springs. Most of the time this involved bigger cams and aftermarket heads.

I went with a very basic setup in my 98, just stock heads, stock length hardened pushrods, Comp 918 springs, and a TR224 on a 112 LSA. The cam was put in using the "dot to dot" method, and the stock springs were simply replaced with the 918s. Was this the wrong thing to do, is that what might help cause my rather low dyno numbers?

Here's the graph again:



Just looking for lost hp....

Manny

BlackSVT03

iTrader: (1)

Hmmmm... Those numbers IMO seem about right for a TR224. Those are about what I put down... but Im also a stalled automatic so mine should be lower anyways.

MannyZ28

iTrader: (1)

Did you do any cam degreeing and lifter preloading and valve spring shimming?

What did yours put down on the dyno?

vettenuts

iTrader: (4)

Degreeing the cam ensures a correct installation, but you also need an adjustable timing set to correct if correction is required. Shimming the springs will give a higher seat and over the nose pressure when required. 918's setup at around 1.765" on a stock setup, so your seat pressure is over 130# that is advertised at 1.800" anyhow. Did you measure your installed height?

Bill Bowling

iTrader: (6)

I installed a 233/233 cam and installed it dot-to-dot. I also installed new springs without checking the height. It does not do you any good to degree the cam unless your chain is adjustable. If your cam chain is adjustable then you can. I am not sure about the springs but I though most of them are direct replacements for stock.

Bill

GuitsBoy

iTrader: (4)

For your application you shoudl not need to shim the 918s, unless the spring install height is less than 1.800.

Lifter preload is not affected by shimming springs. You can only adjust lifter preload with pushrod length, valvestem length, or adjustable rockers.

MannyZ28

iTrader: (1)

Yeah I am clueless with all the intricate valvetrain stuff, hence the rather dumb question. We did not measure the spring height after installation, we were just glad we got them in there j/k my buddy did all the work on the car, but again, we didn't measure the installed spring height.

And my timing chain is non-adjustable, it's a JWIS or Cartek chain that I got from Thunder Racing, it seems a bit beefier than the LS2 chain, but a lot more expensive at 150 bucks.

Well, the car is going in tomorrow to be re-tuned by Mike Norris. I doubt he'll find any more power, but I am not very confident in the guy that tuned it 2 years ago.

Thanks for responses guys!

DONAIMIAN

iTrader: (18)

I dont know about lost HP, but that graph is really broken up at the higher RPM's. Were you getting any KR?

MannyZ28

iTrader: (1)

I don't know... Mr. Super Tuner didn't tell me **** about what was going on with the car...he just said "that's as good as it gets" and that was it.

It may look like it's breaking up coz the smoothing is set to 0....but yeah, I was wondering about that.

What would cause knock retard?

GuitsBoy

iTrader: (4)

I think it has a lot to do with smoothing = 0. I dont think KR would recover fast enough to cause that sawtooth. It also does not fall off like valve float. Smoothing just makes sense.

Justin00SS

iTrader: (5)

You would be at least 380-390whp with the tr224. Thats only 20hp more than I have and I have everything but a cam and u/d pulley.