Car is in the sig. It has roughly 61k on the motor.

I am thinking of going FI but I really dont want to rebuild it as I just had to replace the motor with the one I got in her now. I know they say that 6lbs of boost is ok for a stock internal car but I would rather play it safe and go with one of the kits that run about 4.5lbs of boost.

Now I was wondering what kits are out there work well with stock Lt1 cars or close to it?

Also not as important what hp and tq numbers would be netted by adding one to my car with the bolt ons I have now?

Thanks in advance.

 

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You are right about the 6psi rule of thumb. The problem is that 6psi, let alone 4.5psi, is not going to really change the performance of the car all that much. It is noticible in the SOTP meter (also known as the butt-o-meter) but it's not like all of a sudden the car will be oh-my-God fast. IOW, I don't think it will will be worth the money and time.

Rich

 

I went from 12.36@110.82 NA to 5lbs of boost running 11.37@120

Last year I was seeing 7lbs but added a bigger TB and much bigger y-pipe and the boost dropped a tad bit but performance picked up.

 

You have a stock engine except the blower? That's what the original post was about and if you ran 12.36, it obviously wasn't stock to start with.

Rich

 

No Rich - I've added the GTP4 cam. Other than that the heads and shortblock are completely stock.

I have no idea what a blower would do on a completely stock engine. Sorry - should have clarified.

 

Im not building my car for drag racing. It is for autocross. And as most of you know the suspension is already going to cost me a ton of money.

I wouldnt mind the occasional light to light race or 1 a year track day, but mainly this is a daily driver with autocrossing on the weekends.

I know my car isnt super modded but I do have LT's, full catback, cai, and will have 1.6rr before it would be added. The car is also stalled to 2400.

What would be a likely gain from that point?

 

If you actually do want to play it safe, then don't boost a stock LT1.
-Michael

 

The main issue here is dynamic compression. Skipping the technical mumbo-jumbo, it means that you run the risk of building more pressure in the cylinder than the gasoline can tolerate.

Sure, you can also build so much pressure that the engine parts themselves just fail under the pressure; particularly the stock cast pistons. However, detonation will kill it long before that happens.

You can use things like high octane gasoline (Expensive!) or alcohol injection to keep detonation at bay, but at the end of the day your margin of safety is too narrow to justify the expense of forced induction. (An easy $5,000 and it can go up from there REALLY fast.)


The only reason I can think of why it would be worthwhile is if you have long term plans that call for a blower.

In other words, you buy a centrifugal supercharger and pully it for 5 pounds NOW but plan to pully it for 15 pounds later on, after a complete rebuild.

If you aren't planning something like that, there are more cost effective options to choose.

 

On that note I wouldnt mind buying the P1SC kit that is convertible to different boost limits. I am just wondering if the stock top end would choke the engine once the boost was upped?

What would be the limit of the top end for boosting. I could get a bottom end done up from golen or vre for fairly cheap but the top end would be another 2 to 3k more aswell. Im saving for a wedding and a house now so spending 10 to 15 thousand on my motor setup in the near future is kinda out of the question.

 

There are too many variables to give you a meaningful answer.

I mean, any head will flow "X" amount on the intake or exhaust side with "Y" amount of valve lift, at "Z" amount of depression...

See, the problem is that you're seeking a generalized answer to a question that only has a GOOD answer when it's answered SPECIFICALLY.


A simplistic answer might be to point out that with a supercharged engine, everything you can do to increase flow on the exhaust side is good. Of course, anyone who knows anything about supercharged engines will realize right away that this is only true within a context.

Am I right in thinking that what you're TRYING to do is to insure that you buy parts only once, and that you want to put on power adders that you can use now but have them still be useful when you do mods later?

 

Yes, you are right in assuming thats what I want. I want something that will be able to hold up for now with the stock motor. The only other modifications that will be put in before the supercharger would be larger injectors if needed and 1.6 roller rockers with cm612 springs.

In the future I will be getting a forged 355 with a mild cam, stock heads ported to LE2 or so (unless this new edelbrock intake is really good, then its trickflows), fully ported intake, 58mm TB.

I would be happy as a pig in s**t if I could see upper 500s in hp when Im all said and done so Im not looking to go ***** to walls with power, but I would like to have more than the average racer.

 

Well then, in terms of the supercharger, once you decide which vendor you want to buy it from (Vortech, Procharger, etc...), you should be asking them if you can pully it down to the boost levels you need to keep your engine safe.