Some questions about the different years

[MuRCieLaGo]

Originally Posted by Paul Workman

Agree w/ all said so far.

Here's a link to Marc Haibeck's site.

Mark performs performance upgrades to the LT5. You'll see there that where the 90-92 375 hp motors and the 93-95 motors receive the full treatment, their respective performance is equal.

One thing many don't realize too is the head bolts on the LT5 are MASSIVE, compared to a typical SBC. And, the head bolts of the 90-92 two-bolt block are larger than the individual bolts of the 4-bolt 93-95 block. And, many examples exist of 415, 427, and 441 cid displacements with 2-bolt blocks that are straddling 700 hp, NA on pump gas. Try that with a SBC!

Aside from sharing bore center dimensions, there are no interchangeable parts with the SBC, and certainly no comparison either with the LT5's rugged "bullet proof" reliability or output per cubic inch for a street driven motor.

So, I wouldn't give 2 vs. 4 bolt LT5s a second thought, especially if it is to be fully ported anyway. And, offsetting the 30 hp advantage of the 93-95 ZR-1s, is the additional weight.

Performance wise, it is pretty much a toss-up across the years in stock form.

Thanks a lot guys and thanks for your detailed answer Paul.

Would it cost much to have a '90 motor modded the exact same way that gives the '93 motor these 30 extra horsepowers? Is it doable?

Again, thanks for your patience and I really appreciate it!

[efnfast]

I'm about 5 grand into mods on my 90. Headers, exhaust, ported plenum and IH, chip. Just dyno'd at 397 rwhp, that's 465 at the crank. Can't believe I've added 100 hp the car since I bought it. 50+ to go. That'll be heads and cams. -Steve

[edram454]

Originally Posted by MuRCieLaGo

Thanks for your simple answers!

I'll make it even easier:

Which engine is the BEST? 1990-1992 or 1993-1995?

whatever your best deal is. they made more 1990 zr1 than any other year. they are the better deal thus the better buy. My two cents.

ed ramos #3028

[rmendoza]

What is the benefit of just adding the Haibeck chip?

Can a layperson do it or does it require a knowledgeable mechanic?

[ZRXMAX]

Originally Posted by rmendoza

What is the benefit of just adding the Haibeck chip?

Can a layperson do it or does it require a knowledgeable mechanic?

Marc H does custom recalibrations depending on how your car is set up.

Headers, gears, porting,etc all have an optimum tuning challenge. Marc will get your car pretty close depending on what your car has.

As far as changing the chip... its easy. You do need to pay attention and be careful with the pins when reinstalling the chip. Not hard to do at all.

[RyanChappel]

also in '91, the ZR's went away from the contrasting side moldings/door guards, and went to finishing them with the same color as the car...if a car has the contrasting molding, it is the original year manufacture...IIRC!

It is the main reason I went with the '91


#1929

[Fully Vetted]

Originally Posted by MuRCieLaGo

Thanks for your simple answers!

I'll make it even easier:

Which engine is the BEST? 1990-1992 or 1993-1995?

What everyone is saying here (and some of us have the early cars, some the later cars and some BOTH) is basically don't pick your car based on which engine you think is best from the stand point of the early version or the late version. Look at it as across the board all the engines were the same and then start finding the best car you can afford. Can't get any simpler than that.

[edram454]

Originally Posted by Fully Vetted

What everyone is saying here (and some of us have the early cars, some the later cars and some BOTH) is basically don't pick your car based on which engine you think is best from the stand point of the early version or the late version. Look at it as across the board all the engines were the same and then start finding the best car you can afford. Can't get any simpler than that.

You are absolutely correct Sir!!

[Paul Workman]

Originally Posted by MuRCieLaGo

Thanks a lot guys and thanks for your detailed answer Paul.

Would it cost much to have a '90 motor modded the exact same way that gives the '93 motor these 30 extra horsepowers? Is it doable?

Again, thanks for your patience and I really appreciate it!

Why stop there (at 30 hp gain)? Adding 40-50 hp or more to the rear wheels of a 90-92 is doable with top-end porting and port matching: not too difficult as a DIY winter project!

The thing is, the LT5 in its factory trim is starving for air! This means there is a great deal of "low hanging fruit" available with simple plenum and injector housing porting. Full head porting will add another 20-30 to the wheels in conjunction with a dyno tuning session by a skilled LT5 tuner. (Mine is but one example; making over 430 hp at the rear wheels on stock cams and un-ported throttle body. (see my signature))



This is one of the beauties of the DOHC motors: they will breathe (if when not choked) and make power way up the rpm band too!

And, the LT5 was built to endure. On the engine stand at Lotus, the LT5 test motor was run continuously for over a week, alternating between max rpm (7000+) and peak torque before being torn down and checked for wear. According to accounts, the motor was still in spec and could be reassembled and run some more.

If you really want to understand what the ZR-1 is and understand what the LT5 really is, you need to read "Heart of the Beast" by Anthony Young ("required reading" for ZR-1 owners!)

[MuRCieLaGo]

Again I want to say thanks to all of you who keep answering my questions.

I just don't way to say in 5 years "I should have bought a '93-'95.

I don't want to have ANY disadvantage with a '90, compared to a '93, ONCE MODDED.

1st example:

I own a '93 RX-7. Engine had slight mods in '99, but that was really easy to get. So I don't have any disadvantage when compared to a '99.

2nd example:

Toyota Supras have different engines. 2JZ-GE and 2JZ-GTE. You just CANNOT expect the 2JZ-GE to be equal to a 2JZ-GTE.


That being said, do you compare the ZR-1 situation to a RX-7? I know, my question might be strange, but it is really important for me. I don't want to regret my choice (I did not regret my choice for my RX-7 that I own since 2007).