L31 Vortec swap [Archive] - Corvette Forum : DigitalCorvettes.com Corvette Forums

: L31 Vortec swap


RoidRage
01-11-2011, 07:08 PM
Im knee deep in the middle of swapping my beloved but dated L82 with camel hump heads for a L31, due to my being a paranoid person that was constantly envisioning my motor and heads being slowly destroyed by lead-free gas and modern oils. A shame to dump my L82, I know, but paranoia makes you do things.
A couple of questions:
1. anybody running the stock vortec TBI on a c3? if so, what exactly is involved?

2. what kind of HP numbers can I expect with headers and a carb intake?

3. anyone hot wire the knock sensor to an LED or some other type of device?

4. will i make more power with carb or TBI?

D_B
01-12-2011, 06:06 AM
I toyed with TBI for a customer's project car, as an EFI option.

I saved most of the information and research I did, so when I get home today or tomorrow, I can look through it and post what I have.

I am also working on a current project, an engine for a '67 Camaro, that will use a dual TBI setup. Different than the L31, but similar in a few ways.

Inexpensive isn't a benefit so I hope this isn't driven by a budget.

To be honest, after trudging through all the different options...TBI, TPI, LT1...I realized that it's now almost cheaper and easier to purchase a kit like Mass-Flo or Holley's EFI systems, and bolt them onto your built engine.

The costs are around the same when you factor in everything, and you get pre-programmed self learning kits that are much more advanced than the decade old TBI stuff.

RTGordon
01-12-2011, 07:43 AM
I toyed with TBI for a customer's project car, as an EFI option.

I saved most of the information and research I did, so when I get home today or tomorrow, I can look through it and post what I have.

I am also working on a current project, an engine for a '67 Camaro, that will use a dual TBI setup. Different than the L31, but similar in a few ways.

Inexpensive isn't a benefit so I hope this isn't driven by a budget.

To be honest, after trudging through all the different options...TBI, TPI, LT1...I realized that it's now almost cheaper and easier to purchase a kit like Mass-Flo or Holley's EFI systems, and bolt them onto your built engine.

The costs are around the same when you factor in everything, and you get pre-programmed self learning kits that are much more advanced than the decade old TBI stuff.

:agree:

The stand alone fuel injection kits are awesome if you don't plan on moving up to something like an LSx engine. They are easily programmable for changes and give you consistent performance out of the box.

RoidRage
01-12-2011, 07:47 AM
I toyed with TBI for a customer's project car, as an EFI option.

I saved most of the information and research I did, so when I get home today or tomorrow, I can look through it and post what I have.

I am also working on a current project, an engine for a '67 Camaro, that will use a dual TBI setup. Different than the L31, but similar in a few ways.

Inexpensive isn't a benefit so I hope this isn't driven by a budget.

To be honest, after trudging through all the different options...TBI, TPI, LT1...I realized that it's now almost cheaper and easier to purchase a kit like Mass-Flo or Holley's EFI systems, and bolt them onto your built engine.

The costs are around the same when you factor in everything, and you get pre-programmed self learning kits that are much more advanced than the decade old TBI stuff.

That would be great. expense is not a huge problem, i'm willing to shell out some extra dough if it means more power and no "dead spots" during hard acceleration.

D_B
01-12-2011, 07:59 AM
That would be great. expense is not a huge problem, i'm willing to shell out some extra dough if it means more power and no "dead spots" during hard acceleration.


Okay, that being said, my first suggestion is to get a kit. This will allow you to build the engine you want to, may it be for HP, or TQ, or both. With the stock EFI systems you have limits to your performance. The kits offer you freedom to build a higher performance engine.

Mass-Flo seems very versatile and last I looked it was one of the cheapest.

Holley has a very good user friendly system that you should look into.

I think Professional Products has a knockoff of the Holley system that might be cheaper...but maybe less reliable.

Edelbrock has one too, but I have limited information or experience with that one.

Do some reading and research, and decide if one of them suits your needs.

Slow & Leaky
01-12-2011, 08:05 AM
You're not going to make more power with FI over carb, it's a matter of driveability. Mostly cold engine driveabilty. Mild engines like these should have dreamy driveability with carburetors.

Otherwise I'll be suprised if the L31 makes any more power than the L82. Now's the time you can re-cam it and change that, don't miss the opportunity. Also, a 76 L82 would've had hardened valve seats and wasn't at risk from no-lead fuel.

Regarding the knock sensor, whatever system you use you'll basically want a full professional diagnostic interface. If you use an aftermarket kit, then you'll get laptop software as part of the purchase. If it's an OEM system then you'll need to purchase full diagnostic capability. You should be reviewing the knock data there, making an LED kind of redundant.

Good luck with the project

RoidRage
01-12-2011, 01:59 PM
You're not going to make more power with FI over carb, it's a matter of driveability. Mostly cold engine driveabilty. Mild engines like these should have dreamy driveability with carburetors.

Otherwise I'll be suprised if the L31 makes any more power than the L82. Now's the time you can re-cam it and change that, don't miss the opportunity. Also, a 76 L82 would've had hardened valve seats and wasn't at risk from no-lead fuel.

Regarding the knock sensor, whatever system you use you'll basically want a full professional diagnostic interface. If you use an aftermarket kit, then you'll get laptop software as part of the purchase. If it's an OEM system then you'll need to purchase full diagnostic capability. You should be reviewing the knock data there, making an LED kind of redundant.

Good luck with the project

I had mid '60s 462 camel hump heads in place of the lower compression L82 heads, with out hardened valve seats. as for the knock sensor i was hoping if i go with a carb set up that there was a way to wire one to an in-dash light or something that would notify me when ping occurred.

Slow & Leaky
01-12-2011, 03:12 PM
Ahhh, I see, that makes more sense. Knock sensors for carb'd cars are available thru several places, kits typically run $250ish. Good luck!