Re: Poll: Who has ever hit the rev limiter?
 

Unless your torque and Hp band has changed extensively from stock, you are needlessly damaging your engine by hitting it ESPECIALLY ON EVERY GEAR SHIFT! If your engine is stock, than you aren’t even getting the benefit of better track times, you are going SLOWER.
You know now that I think of it, even if your engine IS modded hitting the limiter cuts fuel and sputters the engine, taking seconds off of your end time. My advice would be to shift earlier than the limiter, there just is absolutely no benefit, while creating a healthy chance for a potentially catastrophic failure..... Why?? :icon_scra

But I must admit, I like your attitude much better than those who keep garage queens... Unless you are just filthy rich and have a collection of course.... But I would still drive the nuts out of a different one each day.

Oh ya and limiter in 5th gear, I couldnt bang it and I was on a very very very long straight part of I-5 in central CA. just had it WOT for some time, got up to about 182 or so, its scary to look away from the road for more than a nano second. And it took an eternity (probably just 15 seconds or so) to climb even one MPH. So Im not sure you can really hit that sucker with a stock motor. I wonder what the top speed of 5th gear is mathmatically (i.e. in a drag less setting). Anybody?

Re: Poll: Who has ever hit the rev limiter?
 

Around 205mph.

Re: Poll: Who has ever hit the rev limiter?
 

But of course even before you hit 205mph and the limiter, your alternator will be generating the needed 1.21 gigawatts and then who knows where you'll end up,... or when you'll end up.

Re: Poll: Who has ever hit the rev limiter?
 

Yep hit while drag racing. Running GSC's and spinning the tires in third gear. If it would hook up I would probably break something!

Re: Poll: Who has ever hit the rev limiter?
 

never hit mine yet but i think my chip has it at 7400 now..I shift at 7000 and it gets to abt 7200 buy the time im done! Works for me! Im am at the point now I can tell the rpm by ear. I was going to get a light but my ear can now tell me when to shift. Took a while on the lt5 compaired to other engines to get a tuned ear for the rpms cause she pulls so hard for so long but afer a couple of years now and some practice I have a handle on it!!! I dump the clutch at 3k for launch and it spins the tires just a bit all the way through first, squaks into second and chirps into third....gotta luv my new chip and alum. flywheel and race clutch, b4 the best was a chirp into second only!!! Now she snorts they way we like it! I dont dump it too often (only to show off to friends mostly) since we all know abt the weak link of the u joints!!! and if u dont have driveshaft loops installed well.... i do have to say the gear rattle is quite noisy and it took a while to get used to it(actually u never really do) and it is a bit funny when people first hear it(they think ur tranny is broken) but once u hammer it they soon figure that it must be ok and healthy!!! lol

Re: Poll: Who has ever hit the rev limiter?
 

TOMTOM72:

With a stock chip in my 91 the shift light will light in any gear except
sixth if you hold speed for a while. Cruising 70 mph in 5th for a few
minutes at constant throttle it comes on. Change throttle position
and it goes out. GM nanny wants to remind you not to waste gas
and upshift.

I never watch the light when I'm hammering it so I don't know
whether it goes on at the rev limit - too many other things to
pay attention to !

Re: Poll: Who has ever hit the rev limiter?
 

Now I just learned why I get such bad gas milage! I'm not paying attention to the General's advice about how to drive my Z! No chit, I didn't ever notice it telling me how to save gas! Oh well no one ever said I was the sharpest knife in the rack!

One thing though.........my secondaries should be really clean! I guess ya can't have everything, hugh?:mrgreen:
:cheers:
Tom

Re: Poll: Who has ever hit the rev limiter?
 

my shift light is OFF :D

Re: Poll: Who has ever hit the rev limiter?
 

not the only light off at your house :mrgreen:

Re: Poll: Who has ever hit the rev limiter?
 

:sign10: :sign10:

Re: Poll: Who has ever hit the rev limiter?
 

HADI HAS THE RED LIGHT ON AT HIZ HOUSE THOUGH!

TILL ROCKSANNE MOVED IN AND TURNED IT OFF!!! LOL

Re: Poll: Who has ever hit the rev limiter?
 

AW i guess poor hopalong is going to be getting the gas for a while. But he seems to be a good sport. Also was nice enough to give us a great sounding video. how do you speed shift with that cast . horefully no holes in the fire wall:mrgreen:

Re: Poll: Who has ever hit the rev limiter?
 

This thread has been very interesting.

The stock rev limiter is set to 7072 rpm. It is set there to preserve the life of the water pump, alternator and steering pump. The engine's redline is 8000 rpm. Above that rpm you risk valve float, although a few members have run their motors above 8000 rpms without issue.

Will it hurt to hit the rev limiter? No. Will it hurt to hit the rev limiter many times? No. Will it damage the engine to run it on the limiter all day? Well - that can't be good for the cam chains or the cams themselves, but the rest of the engine won't give a damn.

Moral of the story - don't worry about touching the rev limiter from time to time. Mine is set to 7400 rpm with a 4.125 inch stroke, which is the same piston speed as running a stock motor above 8000 rpm. I also have larger pulleys on the water pump and alternator to slow them down, use less power and extend their life as I wring it up to 7400 rpm on a regular basis.

As for shift lights - set them 200 rpm below where you have the limiter - shift just after you see the light, and you'll never hit the limiter.:thumbsup:

The stock shift light is too difficult to see to be useful. It was calibrated for peak power on the stock calibration when at WOT, and for fuel economy at part throttle. It was pretty cool.

Re: Poll: Who has ever hit the rev limiter?
 

good info---nice to see ya postin here doc---hope u are happy in yankee land now---

Re: Poll: Who has ever hit the rev limiter?
 

I have been following this thread with a large smile. :-) My rev limiter was set to either 7600 or 7800, I can't remember which. I have banged off of it so many times, I couldn't even begin to guess how many times. I agree with what Dwight says. No damage. That is what it was designed to do. To stop you from damaging the engine. I will say also that I ran my Z very hard and it was used to the treatment I gave it. Even at 105K miles on the engine, it still ran pretty good. Would I recommend that for every LT5, probably not if you don't do it all the time. Do I think it will hurt it, probably not. My engine has done things that most will never see. I have had it 180 mph in 5th with 4.10 gears and held it there for several seconds (BBORR 2001 heading to finish line). I am not sure but seem to remember that it was at about 7400 - 7500 rpm at the finish line. And I had the "pedal to the metal (fiberglass)". With modified engines, going above 7000 makes sense when racing or playing. With a stock Z, there seems to be no good reason to rev much over 7000 as it runs out of air. My car was slightly modified and on the dyno was still producing good hp at 7400. Just thought I would comment. I am sure there are many Z owners who hate what I did to my Z. However, I feel like when racing in ORR, I was doing what the car was designed to do. It is a great ORR car. With just a few thousand dollars worth of mods, it was able to beat a lot of very expensive cars. And give its owner (me) memories to last a lifetime.

Re: Poll: Who has ever hit the rev limiter?
 

Curtis:

I always enjoyed it when I heard of something else No 364 had done or was about to do. Always was courious what would have happend next if 364 wasen't wrecked.


Jan

Re: Poll: Who has ever hit the rev limiter?
 

Hi Jan,
There were two things that I wanted to do with #364: 200 mph and 10 sec 1/4 mile. I did one and will always believe that I would have done the other on Sat. at BG when #364 was wrecked. Now had I accomplished both goals, I probably would have raised the bar but will never know. 11.08@129 will just have to suffice.

Curtis

Re: Poll: Who has ever hit the rev limiter?
 

wow that a great et and mph . what mods did you have to get there? what did you do to the suspension to get it to hook up? love to learn from ya. thanx:mrgreen:

Re: Poll: Who has ever hit the rev limiter?
 

#364 had only a few mods, all bolt on. RWHP was 392. I had the normal stuff done: inj housings, plenuum, headers and 3 1/2 inch SS open exhaust with X pipe. For most of the time I ran 4.10 gears except when ORR then 3.45. For drag racing, I sprayed a little. Best 60' was 1.59. I used 10" ET Streets when spraying and they hooked pretty good. I set front shocks to full soft and rears to 3/4 hard. My FX3 system was disconnected and I set all shocks by hand. Fronts are easy. Rears more fun.

Re: Poll: Who has ever hit the rev limiter?
 

It's north of 7500, I know that!

Re: Poll: Who has ever hit the rev limiter?
 

Corey set mine at 7500 because I was still making good power up top. I bounced it several times today during the autocross on Nellis AFB. I had a blast and all the attendees really liked the way the LT5 was singing!

Re: Poll: Who has ever hit the rev limiter?
 

Hey Ron!
Which car did you drive today?
How did it do? Huh, Huh, Huh?

Re: Poll: Who has ever hit the rev limiter?
 

26 of you really need to go out and drive your cars

Re: Poll: Who has ever hit the rev limiter?
 

I hit mine, briefly, on a burn out. No big deal, just let off the gas.:mrgreen:

Re: Poll: Who has ever hit the rev limiter?
 

Tom, so your shift light actually comes on? Mine doesn't seem to and I thought later GM ECM calibrations didn't turn it on anymore. But maybe I just have a bulb burned out...[/quote]

I have only had my car since last August, but I have never seen a shift light on my car either. I don't know that I want to see it.:wink:

Re: Poll: Who has ever hit the rev limiter?
 

I've never hit the rev limiter. When I dynoed my car I had the operator rev it because I didn't want to do it, he never hit it either-for the reason it wouldn't show more HP or TQ by doing so. I agreed & will probably do it myself next dyno...:cool:

Re: Poll: Who has ever hit the rev limiter?
 

just find your favorite stretch of road and get on it

Re: Poll: Who has ever hit the rev limiter?
 

I'm not sure if my limiter is enabled...that or the tach is off a little. But I can get way over 7K and near 8K without any limiter. I have stock gears and can hit 84MPH easy in 2nd. Is that normal?

Re: Poll: Who has ever hit the rev limiter?
 

Poly bushings will take care of that I guarantee it. :cheers:
http://i301.photobucket.com/albums/n...0/image8-2.jpg
http://i301.photobucket.com/albums/n...0/image7-1.jpg

If your a DIY guy you'll need a 12 ton press and be prepared for a big job. But it will feel rock solid at any speed and have very little body roll around corners.

Re: Poll: Who has ever hit the rev limiter?
 

ah the old tiger shark, but the women in the pic are too pretty compared to the actual ones

Re: Poll: Who has ever hit the rev limiter?
 

Just following along here...

Seems to be a lot of pushrod SBC experience being projected onto a DOHC platform; a platform that was tested by alternating it from max rpm to max torque continuously for over a week before being torn down for inspection. It was deemed ready to go again!

I believe it was in the book "Heart of the Beast" where it was mentioned that the motor was good to about 8000 rpm, and above that oiling was the problem and lubrication-related failures of varous kinds, e.g., cams seizing, chains breaking ensued, as I recall. (However, Fastlane was running his LT5 to the mid 9000s in the quarter, but I never saw anything written about what all mods were done to that motor to address the rpm issue - if any.)

The (approx) 7200 factory limiter setting was chosen as a practical limit because 1) the power curve had peaked around 6400 (stock motor) and was tailing off past practical use, but 2) the main concern was the periphery components - alternator, PS pump, etc. (The AC compressor is shut off by the ECM above 4xxx rpm)

Serious performance is in the offing after porting and especially porting with cams, and cutting it off at 7200 is apparently premature for most properly modded LT5 motors (or certainly the case with the "FBI" modded motors at least).

Cases in point:

Y'all have seen Pete's video where he hits 129.x mph in 3rd gear. (The video done at Great Lakes Dragway showing a couple burnouts and 3 runs) Considering 120 mph is achieved at 7200 in third gear for stock tire sizes, Pete would have to set his limiter north of 7700 rpm to hit 129 mph.

Then there's the 10.x second big inch LT5s running way north of 7200+++ at WOT

After porting my LT5, it was still pulling hard when the danged limiter would cut me off; I hit the limiter many times. I, as well as Dom and others had to bump the limiters to at least 7600 to accomodate (in my case) a 7200 shift point, AND allow some headroom as I hit the 7200 rpm mark way short of the finish line.

Something else...

Some have questioned if their rev limiter was working at all because they had observed the tach sweeping up to or past 8000 without hitting a limiter. I can tell you that before I recalibrated my tach the needle would sweep off the end of the scale before hitting 7200 rpm! It is apparently quite common for these tachs to go out of calibration over time - mine was reading 20% high, in fact (resulting in running off the scale before hitting 7200 actual rpm).

So, I suspect there are some that have been cutting their LT5s waay short of their potential because of a combo of unwarranted concern for reving too the stock limiter setting, and because they're looking at a tach that may be reading significantly higher than the actual rpm. That is too bad, because it is robbing them of the biggest gift the DOHC LT5 has to offer...RPM!;) (I observed this very phenomenon when I let a friend of mine drive my Z while I rode shotgun. He was short-shifting it at about 5800 rpm! I asked him why he wasn't riding it out, and his response was he was going by the sound and what he knew from "regular" V8s. So, I wonder how many Z drivers there are out there that are instinctively shifting their Zs according to patterns long etched into their minds by experience with pushrod putters!?[-X AND, here is a classic comparison between a pushrod LS1 and a stock LT5. Notice what happens to the gap every time the C5 driver has to shift. You'll get a really good view of the beauty of the LT5's reving)

Fuel cut-off is the method used by the limiter. The result of hitting the limiter is the engine will pop and sputter until the rpm is reduced. I don't know why anyone would attempt to hold the rpm against the limiter intentionally - that can't be a good idea (on so many levels). But, bumping into the limiter occasionally is apparently not going to hurt anything: after all, the limit of the stock motor itself is somewhere more like 8000 rpm. (excluding belt-driven accessories - I'd be more concerned about that Chinese-made replacement alternator than anything.:neutral:)

A shift light, e.g, the Raptor that can be hidden behind the vent grill, would be "thee" way to know when to shift without bumping the limiter - AND the lights are much more accurate than the tach, due to the tach's inertia lagging (especially in lower gears).

Uz guys afraid of going above 6500 rpm either have lace on your panties, or have "pushrod characteristics" embedded in your brains, I recon! :p Let that LT5 stretch it's legs and show ya what she'll really do!:dancing


P.

Re: Poll: Who has ever hit the rev limiter?
 

where can one get the raptor shift light .?????and how does it get wired to the car ???

Re: Poll: Who has ever hit the rev limiter?
 

I've never seen a shift light in mine and have reved as high as 8k. But at 8k I do notice the drop in torque. The engine revs faster than my tac needle can keep up with in first gear. I don't make hitting 8k a habit either. 2500rpm drag strip launches may be fine with the dual mass flywheel but not with a Fidanza. If you launch at 2500 with the Fidanza you'll drop like a rock and bog for a second before the rpm's come back up. I've launched mine with the Fidanza at 4500rpm's with Mickey Thompson s. Thats the sweet spot for me. Having a stroked LT5 with a Fidanza may not cause you to bog off the line because of the massive torque and hp they produce.

Re: Poll: Who has ever hit the rev limiter?
 

On the Dunlop street tires I do a 3500 rpm clutch dump.

Having a nice ceramic stage II from CC helps a lot as well on the launch plus my secret tuner chip all have worked well to give extra spunk to the Z.

I really do like the Fidanza a lot.

I shift at 7K on the needle and have only hit the rev limiter once - so I know it works!!

Re: Poll: Who has ever hit the rev limiter?
 

I hit the rev limiter once, I was in 4th gear. Put the hammer down and didn't let up until the needle was right at 7K and that is when the engine hit the fuel cutoff limiter. I don't remember exactly what my speed was I think it was a bit north of 140MPH.

So I think my tach is actually fairly accurate still, being that the limiter is set at 7200, that would mean it was reading only 200 RPM low at that point.

Nearly every time I drive my Z, I do at least one short run through the gears to at least 6K to make sure the secondaries stays clean and working. :mrgreen: And every time it amazes me how it just keeps pulling and pulling! Not to mention the awesomeness of the scream of the LT5 at those higher rpms. Love it!! :-D

Re: Poll: Who has ever hit the rev limiter?
 

top of 4th is probably closer to north of 160

Re: Poll: Who has ever hit the rev limiter?
 

http://raptorperformance.com/products/Shift_light.htm

http://i190.photobucket.com/albums/z...Connection.jpg

http://i190.photobucket.com/albums/z...B/GaugePod.jpg

Re: Poll: Who has ever hit the rev limiter?
 

(I thought I posted this earlier, but now can't find it here. Anywayz..)

Thanks Jerry for the detailed info re the A pillar mount.

The shift light is ever so much more accurate than the analog tach, and when drag racing, ya don't have to be looking directly at it to see it in your peripheral vision - and keep ya from bouncing off not only the rev limiter, but the guard walls too!

I really like the clean cockpit look, so the hidden approach apeals to me. Your mileage may vary. AND, the popular AC vent installation looks like this...

(Note: there are acutally six (or so) leds and on start-up the light says "hello" by turning them on and off in a circular pattern for a second or so. The camera only caught a couple, but when the time comes, all come on, and even in daylight you will not miss it. In fact, I have mine intentionally aimed toward my right eye. As you can see, ya miss it!)

http://i185.photobucket.com/albums/x...aptorlight.jpg

The Raptor is only 3/4" in diameter, and can easily be inserted through a hole drilled in the plastic. Plastic tape is wrapped around the barrel of the lite to generate the desired fit.

Referring to the FSM, the C100 connector is where the white tack wire can be intercepted. You'll have to remove the hush panel to see the connector, located about 2" from your big (left) toe (while driving).

To fische the wires down there, after disconnecting the negative terminal of the battery...very important...you can use a coat hanger wire to snake down to where you can grab it, and tape the Rapor wires to the other end, you can them pull the wiring down to the footwell area and splice them.

Re: Poll: Who has ever hit the rev limiter?
 

:o the only time I hit the limiter on a consistent basis is in 2nd gear. I usually watch the tach like a hawk with my left eye in 1st as I find by not watching closely it is too easy to hit the limiter in 1st. If I shift by "ear & feel" of the motor in 2nd I will always hit the limiter, but then my only other vette was a C3 LT-1 car. So seeing 6 to 7 k rpms on a tach is "normal" for me! Even my DD, Cobalt Sport 2.4 DOHC/4V has a 6.5 k rpm limit on the tach! :redface:



JMHO, but 1st gear ratio is too big ( isn't it like a 2.63 gear? ) for the power available and the stock rear gear ratio. If I had money to waste I would like to see the Z's box with a 2.20 1st gear like the M22's used? That set up in my 72 LT-1, an M22 box with a 3.55 rear gear & 15" wheels, yielded 10 mph per 1k rpm in 1st gear. So 0 to 60 mph was done in 1st without even being close to the factory red line of 6800 rpms. To a road work person, having a "useable" 1st gear is a God send! Those pesky hairpin turns & all ya know.:mrgreen:

:cheers:
Tom

Re: Poll: Who has ever hit the rev limiter?
 

I have never hit the limiter in mine but Im almost 100% sure I have cams in it, the higher you run it up the harder it pulls all the way to 8k. My close uncle has a 90 Z and his " dies" at 6700-6800 ish