Recently I been debating selling my car or going FI (probably turbo). However I JUST put an MS3 cam in my car with supporting valvetrain components this past winter. I been reading a bit on FI and keep reading that "you need a 114 lsa cam or higher" to run FI set-ups properly. I know people debate this but I would like a somewhat straight answer. I don't really want to swap out all the cam/valvesprings/pushrods since I JUST did them, but is it possible (or even smart) to try to turbocharge my car? The rest of my mods are in my sig.


Again I know this has been debated before, but the answer to this is really hindering keeping my car or letting it go. How wild would a car with a big 112 lsa MS3 cam be a turbo (or 2) chargers powering it? Talk about NASTY!

 

Nothing?

 

There are a couple on here running a 112 lsa cam. Sure you'll lose some boost out the exhaust but up in the RPMs might not be so bad. There's been a few discussions over this topic but the consensus is just it won't run to its full potential. One of the guys says his car screams on the top end if I remember correctly.

 

And you wouldn't have to swap your springs and pushrods, just throw a slightly smaller cam in there with the same base circle.

 

Well im going through and issue right now.... i just turboed my NA setup here are NA videos and NA+6psi boost.....

seems to be about the same speed!!! Im not sure if its my setup or my tune or what but damn im kinda pissed!

NA (this was even pretuned!!!) it pulled alot harder after it was tuned and it spun up to 6700 instad of 6000 like and it also didn't hit the limmiter like in this video. This is also on 3.23 10bolt and street tires...
http://s721.photobucket.com/albums/ww216/one_bad_ls1/?action=view&current=taruns.flv

NA+6psi this is on 9" with 3.70 drag radials, ve tuned and 6* timming, and running to 6000
http://s721.photobucket.com/albums/w...=VIDEO0016.flv


maybee i just need to get the spark tables tuned up.... but man im dissapointed!!!! The car was faster tuned pre-turbo!! How is this possible!

All my mods are in my sig.

This is what im going through right now.... lol

 

thats what i was going to say.....use the good valve train parts you have and just get a different cam. Then sell your MS4 in the classified and get some money back on it. Theres plenty of people looking for that cam so it probably wont be around long.

 

cams are cheap compared to turboing...just put a cam thats setup for what you are doing...

 

Depends on what type of FI you are planning, Yes your engine will run with any Lobe angle but it will not be optimal. You can get by with a tighter lobe angle with a supercharger but with a turbo you really need a wide angle, thats why stock cams with 115+ angles work well with turbos..

 

I have no ideal what all your cam specs are cause you didnt list them, But the cam in my 5.3 is a 224/224 .580/.580 112 and I thought it worked ok with a turbo. 15psi and a 50 shot of spray calculated out to around 640whp with stock 5.3 and 317 heads and that cam.

 

I think you'll be getting a lot of boost exiting through the exhaust due to the aggressive overlap on the MS3. Can you do it, sure. It certainly won't be optimal, and if going through all the effort, I'd recommend changing the cam to a more friendly grind.

I did run a TR224 and a STS setup for a while. Even though the TR224 was on a 112LSA, it worked decent (426RWHP/425RWTQ). However, when I switched to a 116LSA Comp grind with similiar lift I gained 27RWHP (453RWHP/432RWTQ) at the same 5PSI of boost.

 

Why on earth are you running 6deg of advance at WOT with 6psi? Best work that back up to about 20ish... Stop at 15 if you are paranoid until you can log/tune, but you will probably find 100 HP in your timing once you get it where it will stay.

 

Hmm thanks for the input guys. Im glad to hear I could leave my valvetrain components alone. As for the MS3 specs they are: 237/242 .603/.609 112lsa

 

.233/.237 .649/.598 on a 112

I've run nitrous, procharger, and twin turbos on that grind. 550rwhp on a 100 shot/615rwhp on 8psi P1sc/787twin turbo and 11.5psi

the cam was fine,....worked great for what I needed. One way or the other, the camshaft will work. Is it ideal,...no but,...what is ideal nowadays?

Try it. I bought a two piece cam door incase I wanted a swap.........I never used it.

 

running 20 right now still no real knock (that I know of, adjusted my 98 kr sensors a little) gonna keep working my way up till I get kr and back it off 2-3*.... it runs like a raped ape now! feels like I gained atleast 100HP... gonna probably run it up to 6400rpm instead of 6000 and get into the cams power-band a little more.

thanks frost....

 

op I wouldn't worry about it try the cam and see how uh does!

 

I wish people would quit propagating incorrect information like, "you need 114+ with a turbo" or the biggie, "you'll lose boost out the exhaust if you have a lot of overlap with a turbo".

Neither are anywhere near correct.

Did you know that the Buick turbo cars from the 80's ran a 106 LSA?

Also, the exhaust pressure is higher than the intake pressure, so how are you going to lose boost out the exhaust? The problem is quite the opposite.

I've never heard of a turbo car losing power with a bigger cam. You should run it and see. However, it should be known that it would take a large turbo to get the full advantage of a cam that size, so keep that in mind when picking the turbo.

 

so when you say bigger turbo do you mean volume or psi?

 

Bigger as in larger wheels.

 

It's funny that you mention that, because every time this discussion comes up, I refer people to turbo Buicks. How can over 20 years of GNX testing be wrong?