DavidPHumes

iTrader: (1)

I'm looking at picking up a used Speed Inc. TU1 for a good price used. It's a 225/225 .588/.558 113LSA cam if I recall correctly.

I'm running a stock bottom end L33 (9.9:1 CR), head bolts, LS9 gaskets, and other supporting mods. Turbo is a TC76 with E85 and I only want to spin to 6,200RPM.

I really haven't found anyone with this exact combo and my fear is that it's too big and will be way too peaky for me (I'd rather have a broader torque curve). But then I found this which indicates it may be not too bad at all:

(ignore the flat power up top, he thinks it was due to back pressure issues)



That's on a 347 9.5:1CR with a TC78, so similar.

Any thoughts? I will, of course, be using good springs (Patriot Gold duals) and nice pushrods.

Fbodyjunkie06

iTrader: (10)

I think it will be fine for your 5.3, but why do you only want to spin it to 6200?

When I had my turbo SS I thought I was spinning it to 6500, but when I went to look back at some data logs I really was only spinning it to 6200. The way it picked up power from 5800 on was amazing and I thought it was really 6200 that it was starting to really pull on top end with when in all reality it was 5800. I can only imagine how it would of pulled if I had spun it truly to 6500.

DavidPHumes

iTrader: (1)

I have a "goal" of a totally stock bottom end, including rod bolts. I know it's RPM that kills them, and I'm guessing stock rod bolts will be fine to 6,500 but 6,200 seems to be the "safe" zone. I may go up to 6,500 but certainly no higher anyway.

DavidPHumes

iTrader: (1)

I guess my other reason is that I can't stand "peaky" cars. I don't want to rev to 7k to make power. I'd rather make all of my power between 4-6k where it's real usable.

Ryans99ls1

iTrader: (16)

i think itll work really well in a 5.3. And youre smart on keeping the rpms low to keep it alive. Im pulling my rev limiter down 6500 and shifting at 6200 to keep my motor together.

cam only i spun it to 6600ish but i wouldnt even think about trying that under boost

jbrenner0188

i had one with no boost and a ms4 cam spinning it to 7200 for 20,000 miles and and over 40 passes with nitrous and never broke

willizm

iTrader: (10)

Wait a second, that graph looks familiar?!?! where have I seen that before.


lol, here is a better graph btw. It wasn't backpressure, but more due to the short filter I had on the compressor causing it to fall off up top and start to collapse my filter. I also replaced the diaphragm in the tial wastegate since it was pinched.

willizm

iTrader: (10)

Also, according to Larry@AMS when I got the car tuned the rpm was a little off

Blue line represents race gas and others are on spring pressure and 12.5 psi on pump.

The last sheet i uploaded was on 12.5 psi on 93 octane

pwrtrip75

iTrader: (8)

The cam is only one piece of the puzzle.. I have one in my 370, and if i had a 5.3 i'd run it in that. It will work and work good.