replacing L98 with ZZ4 crate motor

RISKMGR · 11-12-07, 11:27 AM

Has anyone done this and how did it run?
Is there anything special I should look out for?
Any help or suggestions are appreiciated

Edmond · 11-13-07, 07:52 PM

One of the guys here has done it. But he replaced the TPI with a MiniRam. It was a beast! I believe his was an automatic but he put a 6 speed in there.

It's been done.

Just wait for the responses to come in.

DarkShark · 11-13-07, 08:46 PM

Quote:

Originally Posted by RISKMGR

Has anyone done this and how did it run?
Is there anything special I should look out for?
Any help or suggestions are appreiciated

'91s have a speed-density system... so, you'll probably need a new chip. I think the cam on the ZZ4 will trip the SES light when it sends signals to the MAP sensor outside the parameters of "normal".

You may also want a set of these... SLP runners.

A ZZ4 will benefit from the larger runners. While you are at it- think about a big mouth lower intake. You may also need to get larger injectors- that depends on your new chip. An adjustable fuel pressure regulator would help dial-in the car better when you tune it.

Really, you want to maximize the engine's potential with well thought out parts. The L98 worked well with what it had. The ZZ4 will work better with parts that help it breathe better.

Edmond · 11-13-07, 10:30 PM

Also, the ZZ4 specs are with a carb and headers amongst some other factors. I don't think the TPI will make the claimed power numbers on top of that ZZ4.

86-ZZ3 · 11-15-07, 02:08 PM

I replaced the L98 in my '86 with a ZZ3. I had Edelbrock runners and plenum, and an Arizona Speed & Marine chip installed, but kept everything else stock. The car already has SLP tri-Y headers. Haven't had the car dyno'd so I have no idea what HP it's putting out.

Edmond · 11-16-07, 12:02 AM

I thought the SLP runners were out of production?

DarkShark · 11-16-07, 07:15 AM

Quote:

Originally Posted by Edmond

I thought the SLP runners were out of production?

Huh. Well, I picked up mine from Ebay for about $80 nearly two years ago.

Edmond · 11-16-07, 08:23 AM

Quote:

Originally Posted by DarkShark

Huh. Well, I picked up mine from Ebay for about $80 nearly two years ago.

Wow, that was a steal. Did you port them any?

86-ZZ3 · 11-16-07, 11:43 AM

I'm curious but are the SLP runners fully-siamesed, partially siamesed or individual?

WhalePirot · 11-16-07, 11:13 PM

Quote:

Originally Posted by RISKMGR

Has anyone done this and how did it run?

While I went quite a bit further than the ZZ4, I do run the SD system and it is quite intolerant of changes. I would search for a great chip guy BEFORE you spend bucks, but AFTER you decide what parts you're going with.

Injectors are sized based upon the expected HP. The ECM strives for a perfect air/fuel ratio and it takes X fuel to generate Y power. X fuel is adjusted by injector size, pulse width and fuel pressure. Some tuners like higher fuel pressure and smaller injectors for the spray pattern; others like larger injectors and less pressure. Find ONE tuner that gets results and stick with his formula, if you want to be pleased with the result for your dollars spent.

AZ Speed and Marine is another choice for runners, OR yours may work well. Remember, bigger is not always better.

My engine was spec'ed with a carb and I probably get more power and undoubtably MUCH better streetability than with any carb.

RISKMGR · 11-20-07, 03:20 PM

I will be using the excell 24pound injectors stock plenum and injectors. The work is being done by "the Vette Doctors" ans I am told that they have done this many times before with good results. The engine should run @ 310 HP with @ 375 f/p torque with the stock chip.

Does anyone know who still programs chips?