Turbo C4 guys... advice needed for future...

BowTieBlood · 02-07-2004, 12:24 AM

If I was planning to set up for a single turbo on my C4 in the future future, but do engine mods within a year or two, what should I do to reinforce the engine in general to stand up to the extra boost? How much do I need to lower compression? I was thinking maybe a turbo at like 10 psi or 12 psi, def. nothing more than 12 psi. Is our compression 10.5 or something like that stock? If it was at 9 I could push decent boost right? Thanks for any advice comments, etc. Did you guys modify your engine first or do it all at once?

Bruce · 02-07-2004, 04:54 PM

under boost of 10-12psi will last you a few hrs if your are lucky. Build the damn motor first save your self later trouble

Bruce

Baldturbofreak · 02-07-2004, 05:00 PM

well, as long as it's properly intercooled and the tune is on the safe side 9 psi is feasable. I did it for a month or so. Just remember, with hypo pistons it only takes one mistake. Just ask my poor Lt1's ring lands :lol: As bruce said go the safe route and build a solid foundation-then go for the boost.

Baldturbofreak · 02-07-2004, 06:23 PM

Just use a set of speed pro -22cc dish, forged pistons. good rod bolts or upgrade the rods with eagles or the like. The crank is ok up to about 5-600hp or so (due to the soft nature of boost) But.. how long it will last at those levels is anyones guess. a decnt 1 pc rear main chevy steel crank will do fine. A 4340 non twist forging will deal with all you can give it.
Shoot for 9-1 or so. aluminum headed reverse flow lt-1's with a good coolant like evans Npg will allow 15psi or more on pump gas(intercooled). throw in some smg water injection and were talkin 20+ psi and 800rwhp. All for Around $10,000.

SurfnSun · 02-08-2004, 10:34 PM

boosting a stock motor is like a stick of dynomite with a really really short fuse. Build it first. :yesnod:

Baldturbofreak · 02-08-2004, 11:51 PM

Quote:

boosting a stock motor is like a stick of dynomite with a really really short fuse. Build it first. :yesnod:

:iagree: Got that right bro. Like I said, just one mistake.......

BowTieBlood · 02-09-2004, 11:10 AM

How would y'all compare the dangers in boosting with a weak supercharger vs. boosting with low boost on your common turbo? Obviously same potential problems, but could I safely run like an 8psi procharger on the stock motor as long as I don't get on it until I build it up maybe 5 months later to a 350 or 383 with 9.5:1 or 9:1 compression??? If I put the charger on first, could I survive for a while? I'd say there would probably be a few road trips to and from Austin and Lubbock but that's just cruising at like 70mph.... I could easily avoid any hard launches 90% of the time. I'd have to take it easy ont he drivetrain as well as I haven't gotten deep into modifying that either yet.

If that answer is NO, which I'd understand completely :lol: about how much do you guys think it would cost to build up a 383 w/9:1 compression??? Pistons/rods/guideplates/spring/cam/heads (maybe stage "2"?)/1.6 rockers/crankshaft/30#injectors/fuel pump/52-58mm tb................. would all of that be sufficient enough to hold up to like.... maybe 12-15psi in the future? (of course build quality and brands of the parts etc. will matter, but let's say irrelevant for now)

Some prices I kinda pulled off a few sites put me around $4,000 + crankshaft + labor......... sound about right???? How much for the additional you guys think, and would this car be OK to drive around as is or am I going to feel weak as hell on the pedal?

Thanks again. :cheers:

SurfnSun · 02-09-2004, 06:21 PM

Here's my take on why it won't work....

First there is no "common" turbo for C4s. Youre talking about mocking up a system. Not something that has been R&D'd for sale to the public. How will you handle the tuning phase?

Second, say you do run 8psi on a stock bottom end. What if you get a bad load of gas? one time freak wastegate hangup, vacuum line crack....youre going to end up boosting thru the roof and walking home. Or you get some boost creep in a high gear...done.

To build a bullet proof bottom end the parts are going to run at least 7k + labor. I had put together a price list one time for build a monster short block for my car. Parts alone came to almost 10k if I recall. FWIW Callaway charges 19k for the TT shortblock should you blow your motor. :eek:

Baldturbofreak · 02-09-2004, 06:32 PM

Quote:

Here's my take on why it won't work....

First there is no "common" turbo for C4s. Youre talking about mocking up a system. Not something that has been R&D'd for sale to the public. How will you handle the tuning phase?

Second, say you do run 8psi on a stock bottom end. What if you get a bad load of gas? one time freak wastegate hangup, vacuum line crack....youre going to end up boosting thru the roof and walking home. Or you get some boost creep in a high gear...done.

To build a bullet proof bottom end the parts are going to run at least 7k + labor. I had put together a price list one time for build a monster short block for my car. Parts alone came to almost 10k if I recall. FWIW Callaway charges 19k for the TT shortblock should you blow your motor. :eek:

Yep the wastegate line cost me my stocker.
Guys I just bought a scat 4340 1pc 3.75 crank and 6.0 eagle L19 (rated to 1200hp) for only $938 shipped!!!!!!!!

SurfnSun · 02-10-2004, 05:21 PM

Quote:

Yep the wastegate line cost me my stocker.

That'll get ya every time :thumbs: Thats like a boost controller with no control :lol: