Troy.Blackburn

There are always plenty of threads regarding L98, LT1, LT4 & LT5 mods but not so much on L83 mods. I'd like to hear what some on you have done on your L83 while still maintaining the basic Crossfire design of the engine.

What I'm not inviting is another debate on who's engine is better like so many L98 vs LT1 debates we see.

Thanks
Troy

Troy.Blackburn

Well this thread is off to a "great" (very slow) start not that I actualy expected it to be a "hot topic". The 84 Vette of course as well all know is kind of the "Black Sheep" of the C4's even though it's what startd it all for us and the L83 is a big part of that image.

The Crossfire engine though does have a lot more potential than it is usually given credit for. When I say this please keep in mind I am NOT insterested in starting a L83 vs L98 or any other engine "debate". Many are aware that GM deliberately restricted the air/fuel flow and therefore the power of the L83 by restricting the size of the ports of the intake manifold to approx. 70% that of the intake ports on the heads, they also used less than optimum throttle body sizes, restricting airflow.

The problem they would have had if they had not done this of course would have been that the L83 would have easily out performed the upcoming L98 which was to be their new "Performance" engine.

Many L83 owners have found a great deal of "hidden" power in their engines by port matching the intake manifold to the heads and by porting the Throttle Bodies, others have used aftermarket products such as the X-Ram, others have added roller rockers and cams...

What have you done?

Fubar569

K&N, 7747 ecm, make the fuel pressure regulator adjustable, punch cat...

pepped it up a bit.

several have CFI 383's...most notably elkabong and ben73...ben is deep in the 12's with his and it's still technically a CFI.

myself i will be going BBC...just because...

SHINOBI-X

138,000 mile original motor. The mods below are all that is done,no more. No rocker arms,heads/cam/headers different ECM,injectors...just the cheap stuff.

-Ported stock intake manifold (helped a butt load!)

-Bored out throttle bodies to 2" instead of stock sized 1.813"(went from 550cfm to about 660cfm flow)

-Hi-flow cat,stock 95' LT1 mufflers & stock pipes and sizes

-adjusted stock FPR,bumped timing up,93' LT1 Fuel pump, K&N filter

-basic weight reduction and 180 thermo+200f switch

-3.54 gears in D36


ran 14.30@94.97 consistantly with all the above but now i don't have the 3.54 gears so i will ASSume i'd run a 14.6x@94mph still. Not bad for the mileage and damn near stock exhuast!

Fubar569

not bad at all! mine's best was a 14.68 @ 92.46mph i think...timeslips are around here someplace but i doubt i'll find them. sad thing is on the local superflow dyno it only put down 142.7hp...haha

SHINOBI-X

thats a good time for your mods too. and for 147rwhp thats actually really good too! thats like 190 crank horsepower!

I have another little motor on the side im ready to put in the car in the next few weeks. just a basic rebuild with a heads/small cam,more intake porting and a newer model tuneable ECM. with that i'd hope to drop a full second with drag radials and be mid 13's and remain smog legal. we shall see

Fubar569

mine won't be even remotely close to smog legal, but as a classic i'm exempt from emissions inspections! as long as it's got a muffler of some sort i'm good to go. no AIR, EGR, canister, etc...it'll all be gone soon enough.

i really wanted to do a CFI big block, but for the HP i'm aiming for, even the 2.375" TB's and 90lb injectors would not be able to keep up...and that was a calculation i ran at 25psi fuel pressure too... I'm sure a very mild streetable big block could be done, but like i said, maxed out TB's with SS injectors and 25psi fuel pressure won't cut it for me. that and the 7747 limits me to 6300rpm and my motor is just about in the meat at that point. the crossfire system in the right hands is a very capable system. maybe i'll build a mild 350 for my truck and...muwahahaha

Black84

Ported intake manifold
Gutted cat
Dana 44 - 3.45:1 gears

JoBy

I put a Vortech supercharger on my Cross-fire.

Black84, That is a good looking stock Cross-Fire Corvette on your Avatar

Black84

I would hope so, I believe it is yours is it not?

JoBy

Yes it is! That picture is from late september 1999.

http://www.joby.se/corvette/1999-09-...nout/index.htm

oldace84

Checkout the crossfire forum.
www.crossfire.webhop.net

CFI-EFI

Best "home" ET: 14.655 @ 4400 feet, physical altitude. The weather was fair that day. The DA was 7350'. Corrected for altitude, only, not the DA or the weather, that equals a 13.86 ET. The last time it was at sea level, it ran 2 to 3 tenths faster than it's factored time. Engine: 160,000+ miles. Stock long block. Home, hand ported, intake manifold.

RACE ON!!!

bdaly84

I have an 84 with the following...

Heddman LT Headers
MAD Eliman. Exhaust
Short Shift(4+3)
160 degree thermo w/ Hypertech chip
ZR1 silver wheels 275 40 17(front) 285 40 17(rear)
BFG KDWS's
Cold air Opening
K&N filter
Taylor 8mm wires

Check out Crossfire Injection Forum...great site with all the info you will need for the crossfire motor. This motor has a ton of potential.

CFI-EFI

So what does it run?

RACE ON!!!

bdaly84

The quickest time I had last year, before the headers, was a 15.2 @92....great speed, no trap time. Waiting for the track to open back up!

SHINOBI-X

yeah,sounds like it should be doing that near stock with exhaust and tune-up parts 15.3-15.5 were normal for 84'

92mph is pretty good for your mods without headers. typical mph was only 87mph. 87mph is what mine did even with a highflow cat and flowmasters when i first got it! it didn't run strong then,just barely runnin'

bdaly84

I know the speed was great, but the time was off. I hoping the headers will make the difference in time. Do you have headers?

SHINOBI-X

no,just stock factory headers/manifolds. due to smog in california im not allowed by law to have em'.

But...with my new engine being ready to go in,shortly the break in i'd like to put LT headers on it and just swap the manfiolds back on for smog when the time comes.

bdaly84

Maryland's the same way, but we dont get inspected, just emission tested, either through the diagnostic or roller test. I have the headers and free flow exhaust, but have stock cat, strickly for emissions.