Updates on my '82 Crossfire Corvette...

[Kane]

It's been a while since I posted. Seems I forgot my password. LOL

Anyhow...

Over the years, I have been able to get the 0-60mph time down to 5 seconds flat. Here was the set up that got me to 5 seconds-

• TBs bored to 1.95"
• 454 truck injectors (PN# 5235231)
  
• GM Marine TBI pressure regulator modded into a VAFPR
• TPI fuel pump
  
• DCS Renegade intake
• Erson .465" / .488" cam 224/234 @.05 with 112 LC
  
• Built 700R4 with the governor set to 5.4k rpm shifts
  
• 2k rpm stall
• 3.73 gears
• Dynamic EFI EBL with wideband O2 integrated into an ADC port
  
• Added an IAT & upgraded to a 1990 Caprice 350 engine code N knock sensor
  
• Hooker headers
• True duals
• Magnaflows
• Eliminated the trap door on the fresh air chamber & plugged the heat riser snorkel- set up to breath exclusively through the fresh air chamber (similar to using a ram air set up like on the LS1 Fbodies).

The car manages to hold closed loop perfectly- and, I set the target AFR for 12.2 : 1 during PE mode. Took a lot of playing with the proportional gains and R/L/M settings, but it paid off nicely.

Oh- and this was on OEM smog-era, stock heads. I also left the OEM air pump in place to retain the sleeper look (although the actual hoses were not linked up to the exhaust).


My goal is to get it just under 5 seconds on its 0-60mph time... specifically, high 4s. It's not a drag car- its just supposed more responsive than stock. I want to be able to sneak up on the late model muscle cars. Not to out accelerate them- but rather to give them a good scare.

I've kept the car as stock looking as possible from inside & out. It has a restored interior and show car level paint. The bottom line is to keep it looking period correct but with modern running gear and significantly improved performance. Obviously, when the key rolls over and it starts... the facade of "stock" falls apart quickly. Until then, it's just ho-hum crossfire.

So, here's the latest round of mods...

• AFR 180cc Eliminator heads with 65cc chambers
  
• Upgraded the valve train with 1.6 roller rocker on the intake and 1.52 on the exhaust (should push total lift to the .496 / .495 range)
  
• Parallel plumbed the fuel delivery with an Aeromotive 13301 VAFPR set at 25psi (key-on)

The car sounds amazing and has a lot of throttle response. Over the next couple of weeks I will walk the tune in and get it optimized for the adjustments I have made to it (a la EBL & the WUD). Unfortunately, I needed the real estate for the fuel lines and VAFPR, so I had to remove the air pump this go round of changes.

Grumpy suggested the rockers a few years ago and now just getting around to making the upgrade.

 

[Grumpy]

congrats on the progress, I think you'll notice a modest power improvement with the higher ratio roller rockers,and yes its a nice looking c3 corvette.
I owned a 1968 with a 496 BBC for over a decade and a 1976 with a 350 (briefly)

 

[Maniacmechanic1]

A Higher stall torque converter would help you.
get to 0-60 in 4 seconds.

Kinda of a crap shoot getting the right one the 1st time.
My pick would be a Hughes on a Budget.
More money a Coan Race torque converter.
Spend $700-900 on a Coan.
Have to look at the engine simulation power charts.
Something that flashes to 4000 rpm for your Vette in current state.

 

[Maniacmechanic1]

You hear all sorts of methods and parts used on C3 Corvettes to get the power down.
By design nature on blueprint paper they only have a limited amount of available antisquat traction available.
By far the best way I have seen witnessed is Good Shocks used on all 4 corners.
Carrea shocks were the best made for a C3.

Today its Double adjustable shocks.
Coil overs optional.
Your Late C3 has Fiberglass Leaf springs like all C4 Vettes have.
They work on the street.

Just need good Stellar shocks added on.

 

[Kane]

I was at 20psi (key on) before the head and rocker swap. To keep the same AFR and stay in the ball park of decent INT/BLM (+/- 6) values across the VE table, I had to move to 25psi (key on). That's a 25% increase in fueling.

We often talk about how restrictive the OE heads are- and while we typically use before and after dyno results- I thought I would share this observation as it directly applies to the fueling demands. The empirical comparison of before and after fueling shows exactly what "less restriction and more lift" means to fuel side of changing the air side of the equation.

 

[Grumpy]

or put slightly differently, As your air flow rates increase with larger ports more displacement and longer cam duration and increased exhaust cylinder scavenging efficiency,
your engines fuel demands tend to increase to allow the correct fuel/air ratio, to be maintained at those higher air flow rates.
https://www.corvettemods.com/C3-C4-...ke-Manifold--Crossfire-Injection_p_14318.html

if your thinking of buying a renegade intake upgrade here is a damn impressive limited time sale
http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/

http://garage.grumpysperformance.com/index.php?threads/how-big-a-fuel-pump-do-you-need.1939/

http://garage.grumpysperformance.co...chevy-cams-and-a-few-similar-aftermarket.133/

 

[Maniacmechanic1]

The OE Small block heads are not that great by todays standards.

Big Chevy OEM to have use is 1967-1969 L88 Snowflake Winter Heads.
781 Oval Ports.
1970 LS6 454 Retangular Port.

Pontiac 1970 614 RAIV.
What I have on my TA.
Really do not want to port them because Value is approaching $10,000 for them.

Olsdmobile 1965 425 A heads are best.
On my 65 425 in my 63 Gp.

Agree with Grumpy most aftermarket heads are superior today.

 

[jac1892]

Kane, holly molly I've been trying to do what you are doing for the past year and a half. Now I have a blue print on what I need to do, I admit I don't understand it all, but this is a great blue print..thanks jac1892

 

[Kane]

It's been several months... I was running down a false knock issue. Basically, the wrong combination pf parts was giving me 1-3 counts of knock in decel & on a downshift. I kept pulling 1-2 degrees with no changes that led to less knock. Plugs had no indication of knock- so, was convinced it was false knock.

Couple of things I will pass along about my false knock journey-

• A later model knock sensor won't work properly with the 82 (or 84) ESC.
• Don't use the ESC from a roller TPI car if you are using a flat tappet hydraulic cam- use the 85 & 86 ESC for the TPI Vette.

Anyway... once I got the right sensor and ESC together, the false knock went away.

It is running like it should and with the advance it should have for the heads.

FWIW... I have AFR 180s and am running 34 degrees of spark at WOT in the 90 & 100 KPA areas. I've found that a modified 1986 Vette SA table works quite well.

 

[Kane]

VE table...

VE peaks between 3,400rpm and 4,000rpm, which is consistent with my cam's power band.

Oh- and I punched the TBs out to 52mm last summer. That's helped with breathing too.

Best of all... 0-60mph is in the four and a half second range.