DeadPurpleDog

How much increased horsepower can be expected by adding to a 405 hp ZR-1 a: Haibeck chip. . .K&N? Are there any other relatively inexpensive mods that give a big bang for the buck hp wise? Thanks!

dbriana

Exhaust but thats going to be $700 and up.

Rkreigh

haibeck chip is about 10-15 HP
air filter 0 (stock paper filter is just fine, even on big HP cars)

do the following

headers, exh, ported intake
4.10 or 3.90 gears

many have gotten well above 400 at the wheels which is very impressive

porting the heads and beyond gets expensive fast!

careful as you tread down the dark path

if you really want a modified car, look around and buy one DONE!

much less expensive.

DeadPurpleDog

Thanks for your comments. I'm on the verge of buying a car and struggling with buying low miles on 90 or higher miles on 94 and the difference in hp. For some reason this has been a tough decision for me.

Paul Workman

From discussing this very topic with Marc H, my understanding is the basic difference amounts to the 405 version's plenum and IH are opened up from 33mm to approx 34mm plus some minor cam timing and chip adjustments to get the 30 extra hp. (both use the same cams).

However, after opening the two versions to equal plenum runner diameters (36mm seems to be common for some of the 350 cu LT5s), all else being equal, the difference in performance disappears.

So, I think I would opt for the lower mileage Z, since the 405 hp version is simply just a little farther down the modification path that one might consider. Talking with those that know, it is possible to get pretty close to 400+ RWHP with a 36mm plenum and IH porting, long tube headers, 3" (B&B) exhaust, and a Marc H chip; this w/o porting the heads (and that ain't chicken feed!). It is amazing what hp is on tap with these DOHC, 4-valve engines!

I can tell ya from personal experience, even the stock "375" hp LT5 impresses!! My Z is new to me, and I'm going to enjoy it this summer, and maybe next winter I'll get to grinding. There's just something fun about a little 350 or even a 368 ci motor being able to elbow it's way to the bar and command respect from even 430 hp C6s.

Come join in the fun. For more info, goto Amazon and pick up a copy of "Heart of the Beast". You'll really be intrigued! Prices are going up, so you won't loose a dime. You can't say that about all the C4s today.

P.

Aurora40

If you look at the resonator on a '90-92, and then at the '93-95, I think there's no doubt some of the gain comes on the exhaust side.

Aurora40

What do you plan on doing to the car? The 405's are no doubt stronger stock. But if you mod the cars a bit, headers/exhaust/porting, they should end up about the same.

That said, if they were the same price, I'd probably go with the higher mileage '94 over a low-mileage '90 assuming the condition on both is similar. Er, well I'd probably recommend you go that way, anyway. I personally like the '90 body style best, so I'd probably go with the low mileage 1990, realizing I'd want to do some modding to it and that it will probably need injectors.

DeadPurpleDog

Really interesting reading. . .thanks! Does the chip for the 375 hp engine take the hp to the same place as the 405 hp also with the chip? Again, thanks so much for the information! Peter

Paul Workman

Good catch. There's quite a bit of difference. I understand that some are running with the LT4 resonator to get better flow. Me? I'm saving my nickels and dimes for a 3" B&B and headers to go along with P&P of the top end, and maybe a 410 to go along with it.

Bottom line tho, the LT5s really appreciate the better breathing exhausts - especially the 90-92s.

Good post (as usual)

P.

dbriana

Why have you not jumped on the 94 since you seem to be getting an
$8k discount?

DeadPurpleDog

Not sure where you got the $8k discount. This is not an impulse purchase for me. From my perspective, the market is weak and will probably continue deteriorating along with the economy throughout the year. . this is a buyers market. I'm planning on keeping the car until I can no longer get into it. . so the right choice is important. I've learned alot here, and from speaking with owners which is helping me to develop an informed perspective. At the end of the day, the 94 may just be the right choice. . I'll know better after I look at the 91 gray/blue with 9k this weekend.

dbriana

Corvette Mike has what seems to be the '94 you are looking at for $32.9K, also 40k, B&B, & chip. If the 91 steel blue/blue is within your budget that would be the best

rogerzr1

but I may be a little biased. The steel blue/steel blue combo is definitely a rare one.