Nacho_ZR1

Hello,

I am the new owner of a 92 ZR-1. Just curious to see what everyone's opinions are regarding the best bang for the buck mods?

Happy Holidays

YorkL8apex

Port and Polish intake plenum and injector housing with a chip seems to be pretty effective for a reasonable price at places like South GA Corvette and other ZR-1 tuners.

Light flywheel and gears give more POP in reponsiveness.

Headers with high flow cats.

Open air filter cover with K&N does not hurt.

Redline7g

An exhaust and a chip are great starts. The stock exhaust is very restrictive.

Nacho_ZR1

Yea it's weird. I looked under the car and you can plainly see it has the stock pipes but Dynomax mufflers. The exhaust tips are the traditional ZR1 rectangles. All I hear on this BBS is Corsa, B&B and Borla. Are these mufflers very old or are they still used today???

Paul Workman

I did my mods over a couple seasons (winter projects); still having a stock bottom and cams. Latest dyno pull showed 432 hp at the rear wheels or something like 508 ish at the FW (if that matters).

The first boost came from P&P of the plenum, the IHs and porting into the heads, and a Marc Haibeck chip. Holly cow, what a boost!

I then installed the headers and X pipe, eliminated the resonator (restrictive as hell!) and went with Magnaflow muffs (had them handy). Honestly, the seat of the pants was not on the same order as the P&P, but a nice boost anyway.

The next "Holy COW" came after also porting the heads...HOLLY COW! This last change is still fresh, and I'm still getting used to how it handles. It is a completely different animal (emphasis on "animal") now!

Next stop: 4.10 gear in the rear. My 60 foot times need to come down some more, I need to go to drag radials, and since I hit the rev limiter in 3rd a couple hundred feet before the trap, I need to shift once more...I guess.

That said, maybe the biggest and quickest and cheapest bang for the buck might have been to go with the rear gear first. If I had it to do over, I might. However, the top end P&P didn't cost me anything but some gaskets and my time. So....

P.

MRDZR1

The guy said "band for the buck", to me this is easy bolt on stuff like exhaust, chip, air box & a 3:73 to 4:10 gears. This will help give her a bit more punch.

Aurora40

FYI, the resonator is far and away the worst part of the '90-92 exhaust system. For cheap you could have it cut out and replaced with an LT1 or LT4 resonator (LT4 is supposedly the freest flowing). Keep the Dynomax cans if you like the sound.

I did this on my car and picked up almost 25whp. I did have a ported intake at the time, so possibly that magnified the gain:



Here's what the stock 1990 resonator looks like, notice how much it tapers going into it:

Graybeard ZR1

Here are my boltons, in descending order of effectiveness, on a stock engine 91'. Estimated cost does not include installation.

Stock engine with: -

Watson headers - $1,000

4.10 Gear - $1,500 (new pumpkin with set-up gears, save stockers)

3' Exhaust (B&B) $1,000 with X pipe, no resonator.

Light. weight flywheel - $500 (do not buy or install without first listening to ZR1 with one at idle. They rattle.)

"Forced Air" intake - $350.00

Bee Cool radiator - $400.00

160F. Thermostat - ?? A $20.00 part that I paid $35 for, and you will now pay over $100.00 (Ripoff).

Hurst shifter - $125.00

BFG Drag Radials - $300

These prices are just estimates as these mods were done more than a decade ago and some of these parts are not available new, but can be bought used.

Performance results:

New (3K mi. breakin) Qtr. Mi. - 13.20@ 110mph. (greenhorn driver)

With Boltons - (best) 12.06@117mph. in Fl. heat and humidity. With good air and cool temps...elevens??

On the street it kicks *** in first and 2nd. Loud as hell, and hate that rattle. Love the car

Goldcylon

Best bang for buck Longtube headers, open air filter element and a retuned prom.

Followed by Fridanza flywheel, porting topend etc etc

Nacho_ZR1

You guys are awesome - love all the responses! Looks like exhaust and gears are what I need to focus on for now. I live in Dallas TX. Do ya'll have any recommendations on who can do the gear install?

locobob

Remember that gears are a trade-off, be sure you can live with them before pulling the trigger.
Exhaust is a great way to start, highly effective and prepares the engine to handle any future mods.
Porting the intake yields good power gains with no downside if done properly.

Graybeard ZR1

Gears are almost always a trade off, but I think that this car stock, is seriously over geared for emissions and mileage at the factory. To me, sixth gear is virtually useless at highway speeds.
With 4.10 gears it's easier to drive around town, still gets 25mpg on the road. And can do 175 -180mph.
Even with 4.10's it still can't pull top speed in sixth, so you know you're not buzzing it to death.
I have 4.10's, but if I did it again it would be 4.56's and stickier tires

Nacho_ZR1

4.56's ?!?!?!?! YIKES!!!!!!!!

rickyrj1

Make a list of all the above Mods, then do them ALL! maybe not at one time but chip away at it. I could not be happier with the results The only thing I want to do is maybe 3.73 gears. I have a set of Viper 4.10's brand new if anybody wants to trade

902066

PM sent

Zrxmax

That is what I thought... way to much gear for the street for me. Some guys might like it, especially the guys focused more on drag racing.

I had 4.10s and liked em a lot... but, they broke at a 120 mph one day. Never understood why...

Went to 4.33s and it was to many rpm on the freeway... around 100 mph was about 3 K on the tach in 6th gear. The traction factor was fun at first... but not real practical for getting the most out of that big torque band.

If you do all the mods I would go 3.73 or 3.90. The gears make for a sportier feel overall with a tad more responsivness. The gears make the car more fun to drive imho.

I never removed the 3.07s from my car because I always think I will be running in an ORR event. I only use 6th to make sure it is still there!

LT5corsa

Bang for the buck are headers and exhaust first. (get a chip from Marc Haibeck)

Fidanza is a great upgrade too!

Goldcylon is living the life doing all the mods and having it as a daily driver too!



David

cv67

Corey Henderson is in Tx he does plenty of ZR1 work and is a trusted guy.

Graybeard ZR1

I never removed the 3.07s from my car because I always think I will be running in an ORR event. I only use 6th to make sure it is still there! [/QUOTE]

Well, different strokes for different folks, but this begs the question, "What kind of driving are you really doing with this car?"
The guy with 3.07's has an ideal gear to go out and set a top speed mark, (in 5th gear), every time he leaves the driveway. But ends up with a useless 6th gear, try to cruise in 6th at 80mph with the 3.07's = 1,575rpm, the ZR1 does not like this at all.
I'm the guy at the other end of the spectrum. I want decent mileage at highway speed, and great acceleration in first through fourth.
With 4.56 gears you can cruise at 80mph in 6th gear at 2,300rpm., not too high for decent mileage, but perfect for the qtr. mile. You would be running through the time traps in fourth gear at less than 7,200rpm around 120mph.
I have 4.10's in my car, a compromise for better mileage, that allow me to run the qtr. at just over 117mph around 6,300rpm. With those gears i've got another 900 rpm's to go before the rev limiter kicks in, not ideal.
My point is, we have a transmission with a .490 top gear, the LT5 will never be buzzing it's little heart out when we have a 6th gear that can, (theoretically), take it to 320mph at the red line with the stock ratio.

Nacho_ZR1

Wow how the heck do you break 4.10 gears? That's gotta be scary!