C4vettrn

Ok don't laugh I am just curious about somthing. I don't think it's possible with my current setup but here goes. I have a pretty standard 383ci setup with 10.8:1 compression. Is there any type of forced induction setup I can run on my motor without changing heads/comp ? I am probably around 425+ HP (never Dynoed). I would love to get 50 or 75hp more somplace. I don't want to convert to E85. I stilll have the LT-1 heads with bigger valves and a little bowl work and porting, dual springs and roller rockers. The intake is a ported stock LT-1 setup with 58mm TB.
Would I be better off replacing my heads with some AFR or Pro-1's?
I don't think it will give me those gains wanted. Oh! off the top of my head I believe the cam is like 224/230 duration and around 530 lift 112LSA. 3,000 rpm stallspeed and 3:45 gears.
Any thoughts?

LT1inaMGB

This is what I'm going to try with a Vortech S trim. I have an LT1 with the block decked to provide .039 quench (helps prevent detonation) giving about 11:1 compression. I have a 230/236 cam with a 110 lsa that should also provide some help with detonation. The engine has 60# high impedence injectors. The big key is water/methanol injection. I'm going to be spraying it through a 14 gph jet with a 250 psi pump at anything over 2 psi. I won't have it running for a few months and will get it tuned immediately. I'll start out conservatively at 4-5 psi boost and go from there. One thing that encouraged me is a friend who had a stock LT4 (10.8 compression) with the same blower kit that I have and he saidf he was able to run it 7-8 psi without water injection.

Jim

mnstrlt1

Hi guys, I thought I'd provide some insight. I wouldn't be afraid of the compression. Yes, 10:1-11:1 is "high", but being conservative is the name of the game here. The problem is that people get "greedy" with the boost, and end up turning up the wick (at some point) to extract more power.

AFR heads are getting pretty pricy ($2,000-3,000), and I'd spend my cash in a different method before going that direction (for your power goals).

Typically a stock cam is pretty "blower" friendly, as is your current cam (with the 112 LSA). Anything numerically less isn't really ideal for a blower/turbo application (I.e. 110 or 108). Ideally, you want 113-116 LSA.

With a blower car you eventually want stiffer valve springs, and more lift benefits any application (generally).

The V2 or V1 (older head unit) S-trim would be a more "efficent" supercharger for your intended goal (you would be working in the parameters of the blower), but most guys eventually step up to the T-trim (supports more air flow). 5-8 psi will be safe with the S-trim and won't necessarily need an intercooler, but methanol injection is a nice insurance benefit. I ran 9psi on my stock lt1 (daily driver) for a few years before planning an extreme build. Keep in mind, the boost climbs with RPM, so the engine can service for some time so long as you avoid flogging it too much/often.

"Best bang for the buck" would likely be rear-end gears and a 75-150 shot of nitrous. I'm not going to get into the potential issues with nitrous, but I firmly believe that a properly set nitrous system will be perfectly fine (need to keep an eye on fuel pressure). Again, don't get greedy.

lcvette

disregard, just saw you did not want to convert to E85, that was my suggestion... and is the best one if you want safe power with boost at your compression ratio.

as it stands I disagree with being able to run up to 8psi non-intercooled safely on 10.8scr motor with a cam that small. you will be on the ragged edge and if she gets just a bit off in the tune for any reason you might be replacing a broken slug. for boost in that range I would definitely be safeguarding the motor and opt to be intercooled or at a minimum with meth injection preferably both.

out of curiosity, what is your reason for not being interested in E85? I know it would require an upgraded fuel system, but for the power it can support its like $3/gallon race gas that burns cleaner keeps the engine cleaner and loves boost. is it a matter of pump convenience? or???? looks like you have 8 stations spread around Fort Wayne...


Chris

C4vettrn

I really don't know much about E85 other than it takes more fuel to make the same power as gas. Most of the talk against running it is mostly related to naturally aspirated motors though. What is needed other than a 255lph pump? bigger injectors I would imagine? Can I run E85 and not need a intercooler/meth inj.? How easy is it to find when traveling and is there certain suppliers that sell it at all there locations? I am willing to investigate the concept of converting as long as it is readily available and doesn't cost more than mogas. Thanks!

mnstrlt1

You'll typically burn about 30% more (by volume), but you will extract far more power than pump gas. Larger injectors, larger pump, any fuel lines that cannot withstand alcohol must also be replaced. I ran E85 on my 12' Mustang, I was converted from that point forward.

mnstrlt1

Oh, going "exclusively" to E85 might be restrictive. I have several options locally, but my 12' mustang was programmed with a hand-held tuner, so I could switch fuels if I had too. I'd make sure I planned accordingly for interstate or nationwide travel. Expect worse MPG.

lcvette

mnstrlt1, pretty much summed it up, and for NA guys it also makes more power, but to take advantage you need the motor setup for it. it likes higher compression, upwards of 13:1 which will also allow you the use of s significantly bigger cam... and voila 500+rwhp on an all motor lt1.

you will burn more e85. but you will make much more power more safely then pump gasoline. motor runs cooler and cleaner too. intercooler is still recommended as e85 doesn't cool as well as methanol.

there are websites online that tell you where stations that carry e85 are. that's how I knew there were 12 stations in Ft Wayne. in a pinch if you have an adjustable fuel pressure regulator, you can calculate the difference in pressure required with your injectors and drop fuel pressure to run gasoline, I wouldn't get on the car like that but it won't leave you stranded in a pinch.

Chris

uxojerry

Contact AFR and tell them what your goals are. There is a good chance you can meet your goals with new heads and cam.

C4vettrn

Will I need bigger injectors or just up the pressure or new tune? I am running 32lb Bosch III's now at stock pressure.

mnstrlt1

the ideal method would be to check your injector duty cycle and AFR. Although,most likely it's safe to bet that you'll want to step up to a 42# injector. Ford racing injectors are great (direct replacement), and affordable. With chevy fuel pressure, they will flow slightly more. Also, a decent in-tank replacement pump would be "cheap" insurance. Don't forget the fuel lines also need to be replaced (the "soft" lines, not the hard lines).

lcvette

60lb injectors
Stealth 340lph intank
check your soft fuel lines replace as necessary
Replace fuel filter
Adjustable fuel pressure regulator
Custom Flash Tune for the setup you are running

I would call that the minimum fuel system upgrade for any kind of forced induction. chances are that you will even outgrow that system if you like going fast, but it would take alot to do it.

mnstrlt1

Ops, I was thinking NA, since his power goal was 425rwhp.

C4vettrn

Hey guys what you think about the $700 complete turbo system that just come up for sale? Price is right, is that brand of turbo any good?

lcvette

No worries.. I got your back man!!!

lcvette

$700 TURBO KIT WHERE? Never heard of anything like that before but I know what they cost and I would say unless it is used and a rear mount of sorts and either really trashed or not functional in someway.. not a very good idea. that sounds about $9k light for a quality turbo system new for a C4 corvette since they are all one off built snowflakes at the present.

Chris

C4vettrn

Sorry! I should have said the used kit that is for sale on the C4 Forum. He does say it is leaking so I Imagine a rebuild would be in order. Is it expensive to have a Turbo gone through?