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I been reading up on the ZR1, looking at my C4 book and these boards.
What i want to know, is how the car runs when you flip the power switch from normal to full. Is it a night and day difference? I would think so, going from 200hp to 375(or 405)? And how do you guys run your cars, normal, or full power all the time? Any issues with running in 1 mode more than the other? Also how does it run in normal, when you get on it a bit? Or in full power mode, how does it run if you just baby it along?
I just think it is waaaaay cool to have a factory power switch that enables this big shot of power. I can only dream of owning one of these amazing rides......
Yes there is an incredible difference in power, but remember the power switch enables the secondary injectors to come on above 3k.
In most normal driving you would not be above 3k unless needing to pass,show out, or get the true understanding of 4 cam power
The LT5 shines in the upper RPM's and pulls strong to 7200 rpm, that's what it was designed for high rpm top end power.
I never turn the power switch off, ever!
If you want a ZR-1 now is the time, rock bottom prices that are trending up for nice cars.
Ok, good info, didnt know about the 3000 rpm kick in. Makes sense, the redline for a ZR1 is at 7000. With a M6 tranny, i am sure it wont take much to get it above 3000. When I get some things finished up with my L98, i might think about upgrading. My 90 has the M6 tranny, and it is very much fun to drive, so i wont likely get bored with it.
How is the mpg as far as the 2 modes is concerned?
Ok, good info, didnt know about the 3000 rpm kick in. Makes sense, the redline for a ZR1 is at 7000. With a M6 tranny, i am sure it wont take much to get it above 3000. When I get some things finished up with my L98, i might think about upgrading. My 90 has the M6 tranny, and it is very much fun to drive, so i wont likely get bored with it.
How is the mpg as far as the 2 modes is concerned?
They pull strong to 7200 rpm actually.
Fuel mileage has never been a concern for me, so I can't honestly answer that question.
IMHO it shouldn't be a factor in owning. History of why and how it was manufactured is the reason to own one.
Fuel mileage has never been a concern for me, so I can't honestly answer that question.
IMHO it shouldn't be a factor in owning. History of why and how it was manufactured is the reason to own one.
O i agree on that as well, just curious about the mpg. My C4 book says they do better than an L98, as long as you dont go above 3000rpm!
There is no substitute for the LT5, and no equal!
the 90 and 91 years had the most production, after that 502 or less cars were made. I will take a '93 in Ruby Red!
The best advice I can give you is this, find the nicest car you can for what your budget will allow.
Do not get caught up in the HP diferences as their minuet.
245 Ruby car's produced equates to Scarce!
Good advice, but if you want the car bad enough, you will pay the asking price. So budgeting doesnt really help you.
245/448 ZR1s in RR, is more than half. I will take those odds! In 93, it was the popular color, for the 40th anniversary model. I imagine that will drive the cost up even more. It will be a year or 2 before i am ready for a ZR1. Sure, i am watching the prices. I paid 9k for my L98, so i figure it will be about half of what a ZR1 will fetch.
Actually the secondary's open by a combination of RPM'a and throttle position or %. Key off normal Corvette key on ZR-1. Most have the prom changed to default the key on.
Actually the secondary's open by a combination of RPM'a and throttle position or %. Key off normal Corvette key on ZR-1. Most have the prom changed to default the key on.
All good info, thanks. Will save the sites for future reference. So it looks like the secondaries need to be "excercised" to prevent future problems. I do my own PROMS in my current C4, so it will be interesting to see what goes on in the LT5 ECM.
I have never even seen a real ZR1 in person, only pictures. Been to a few shows, and cruises with my C4, but there has never been a ZR1 around where i live.........
......that seems to be the general mode of operation! So the normal mode really is a "Valet" mode.....at 210 hp, good enough for him.
Also, i assume the key can only be removed in the "normal" mode....
If you were in normal mode, and needed the power fast (for any reason), might not be easy to switch it while driving and shifting!
......that seems to be the general mode of operation! So the normal mode really is a "Valet" mode.....at 210 hp, good enough for him.
Also, i assume the key can only be removed in the "normal" mode....
If you were in normal mode, and needed the power fast (for any reason), might not be easy to switch it while driving and shifting!
The '90 model power mode is default to full power. The following years default to normal power and at least on the '91 the switch is spring loaded. When you turn on full power, the switch goes back pointed to normal power with the green light on indicating full power. And the key is removable on either power mode.
If you ever get the chance to drive a ZR-1, I guarantee you will own one sooner than expected
I been reading up on the ZR1, looking at my C4 book and these boards.
What i want to know, is how the car runs when you flip the power switch from normal to full. Is it a night and day difference? I would think so, going from 200hp to 375(or 405)? And how do you guys run your cars, normal, or full power all the time? Any issues with running in 1 mode more than the other? Also how does it run in normal, when you get on it a bit? Or in full power mode, how does it run if you just baby it along?
I just think it is waaaaay cool to have a factory power switch that enables this big shot of power. I can only dream of owning one of these amazing rides......
1st I will say is these are great engines. they don't have problems dropping valves are cratering blocks like the c6 Ls7 and problems that are surfacing on the new LT based motors on the c7.
I had a c4 Zr-1. I always left the power key on. the secondary injectors and butterflies in the injector housing don't come on until about 1/3rd throttle and 2500 to 3000 rpm as i recall. They stay closed at lower RPM for enhanced torque by design.
It doesn't run that slow with the key off. I think it weens back from 375hp on the 90-92 lt5's to 200-250 hp.
With your foot on the floor and between 4000 and 7000 rpm there is a huge difference. A few times in my c4zr-1 I would floor it with the power key off then reach down and quickly flip it on in the 3500 rpm range. There was a big difference in the intake noise. Sounds a bit like an old style 4 barrel carb motor with the back barrels kicking in.
Overall I think the C4 is a more stable platform then the c5 and c6. These new cars feel twitchy to me compared to my c4 zr-1, maybe thats due to the tires on the c6. The c5 and c6's don't rattle as much, but maybe thats due to better sound deadening.
The C4 Zr-1 with the Lt5 set the 24 hour land speed record averaging 175mph + for 24 hours. You couldn't average 175mph in these later model corvettes for 1 hour let alone 24 hours. the LS and LT based motors would blow apart.
At 100% throttle the secondary's will open as low as 500rpm's but the real power comes on as you stated around 2500rpms until fuel cut off 7200-7400 or what was set in the prom.
Light weight FW and free flowing exhaust no cats would add another 15+ RWHP to this.
What are these secondaries you guys speak of..........
Mine are gone, the car makes almost 700 engine HP, and it got 23 MPG, at 75 MPH, with the A/C on, back and forth from Bloomington..pretty good combination I would say. The 415 gets better fuel economy than my mostly stock 350 '90 did....I don't get it.
1st I will say is these are great engines. they don't have problems dropping valves are cratering blocks like the c6 Ls7 and problems that are surfacing on the new LT based motors on the c7.
I had a c4 Zr-1. I always left the power key on. the secondary injectors and butterflies in the injector housing don't come on until about 1/3rd throttle and 2500 to 3000 rpm as i recall. They stay closed at lower RPM for enhanced torque by design.
It doesn't run that slow with the key off. I think it weens back from 375hp on the 90-92 lt5's to 200-250 hp.
With your foot on the floor and between 4000 and 7000 rpm there is a huge difference. A few times in my c4zr-1 I would floor it with the power key off then reach down and quickly flip it on in the 3500 rpm range. There was a big difference in the intake noise. Sounds a bit like an old style 4 barrel carb motor with the back barrels kicking in.
Overall I think the C4 is a more stable platform then the c5 and c6. These new cars feel twitchy to me compared to my c4 zr-1, maybe thats due to the tires on the c6. The c5 and c6's don't rattle as much, but maybe thats due to better sound deadening.
The C4 Zr-1 with the Lt5 set the 24 hour land speed record averaging 175mph + for 24 hours. You couldn't average 175mph in these later model corvettes for 1 hour let alone 24 hours. the LS and LT based motors would blow apart.
More good info. The more i read about it, the more i like it! And it looks like i should be calling it a ZR-1, instead of no hyphen. I think they made one newer than a C4, for like 1 year? I dug out my '90 C4 FSM, and started looking at the LT5 section. The ignition system is way ahead of its time! And it says the HP is limited to about 210 in normal mode. One of my books says the C4 handles better than a C5! I do like the interior of the C5, however.
12-29-2014, 08:36 PM
Question about the LT5 engine....
