When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Thanks for the comments, guys. Glad that folks are appreciating the info posted.
Originally Posted by 93 ragtop
They don't get in trouble for underrating, but overrating is another story. Just go ask mazda about their RX8
Or Ford about early Cobra's and Marauder's.
It always hard to know if a dyno is telling the true story or not. Adding different brands of dynos into the mix complicates things further. A car with low gearing, heavy flywheel and big heavy wheels and tires will do poorly on an inertia dyno, but well on a steady state dyno. Opposite of that is a car with a light, drive train. I have a friend who has a 175k mile, stock '88 5.0 (can you believe one exists!?), except for LT headers/cat back and UD pulleys. He just put down 239 RWHP and 309 RWTQ....but recently ran 14.6's at Vegas. Is he making 238? I'd say no. He has an 11 lb flywheel, T5 transmission (light, small gears, low friction), 2.73 rear gears, and 16" wheels. On an inertia dyno, those features are going to conspire to help make that engine look better than it is, relative to other cars on the same inertia dyno with heavier drive train.
Anyway, I like the repeatability that I saw with mine. Out of 3 pulls on Dyno jet dynos (including two different machines at two different sessions), the results were 276, 277, & 278. Are the numbers "strong"? They appear to be, and that strong data is backed up at the track were I run faster than any stock LT1 that *I* have ever seen (at my track).
It's a strong running car and the dyno results back that up. As I would expect, the 155k miles combined with decent maintenance results in an engine that pulls as hard now (or harder maybe) as it ever did. I was definitely interested in seeing tq at 1000 RPM. Dyno operator didn't quite get is that number, but we can see that it's at ~275 rwtq at 1200 RPM.
Tom, it would be nice to see stock L98 and Stock ZR1 runs as well especially with a manual transmission. But there does not seem to be too many stock one's being dyno'ed. At any rate, thanks for running the car and posting the results!!
I think engines that are ran harder ie. see redline at least once every time they are out, make more HP and run better, than engines that rarely see Redline and live a sedate lifestyle kinda on the slow side.
I cannot prove this but it seems to hold some merit.
I completely agree, but have to HARD data to prove it. But ALL my cars have been driven hard and have also produced better than average numbers. My LS2 C6 did 360 RWHP, which is about 20 better than the averages that I've seen.
Originally Posted by 93 ragtop
Tom, it would be nice to see stock L98 and Stock ZR1 runs as well especially with a manual transmission. But there does not seem to be too many stock one's being dyno'ed. At any rate, thanks for running the car and posting the results!!
I agree. It would ne nice to see some stock L98 data.
I completely agree, but have to HARD data to prove it. But ALL my cars have been driven hard and have also produced better than average numbers. My LS2 C6 did 360 RWHP, which is about 20 better than the averages that I've seen.
I agree. It would ne nice to see some stock L98 data.
Tom, I am trying to dig up my runs on the Mustang dyno in Phoenix. On the mustang my best pull on a 85 L98 bone stock was 223. I have no idea of what that would be on a DynoJet.
Went to our track on Saturday for T&T -my first drag-track outing since last May. Goal was to get another number that started with a 13, just to make sure that the car is still getting it done, and that *I* can get it done!
As for a number starting with a 13, remember; high elevation here. Track is at 4200', the DA on Saturday was a low (for us) 6500'. Most LT1 'Vettes run mid 14's at our track.
Cleaned the tires, staged, launched at ~4k, flat-foot shifted @5500, and in one run I got it done. 13.74/101. Fastest the car has ever gone here.
Then I left the track and went to watch the Supercross. What a day!
Street tires. Bridgestone Potenza RE760 Sports. Nothing special. This car hooks good so the hardest challenge for me at this elevation is finding that balance between bog and hazing the clutch. I go from ~4k and spend about 1.5 seconds slipping the clutch. I didn't do a great job at that last night in my 1 pass, but can get my 60' to 1.9x if I do it right. Dumping gets me a bog and 2.1x 60's, and going higher than 4k ends up in wheel spin with a dump and too much heat for the stock clutch with some slipping.
Correcting that to Sea Level is 13.0@106. Dang, that is a strong LT1.
I REALLY want to try mine with the fresh valve springs now.
As we have discussed in the past getting good 60' times with a ZF6 C4 with street tires is an art. I don't think a STOCK LT1 ZF6 on street tires can do better than a 1.9X. I have yet to see it. My best was a 1.99.
As we have discussed in the past getting good 60' times with a ZF6 C4 with street tires is an art. I don't think a STOCK LT1 ZF6 on street tires can do better than a 1.9X. I have yet to see it. My best was a 1.99.
I've hit a 1.86 60', but my car is not stock. I launch off idle, rolling into the throttle as I slowly release the clutch. The throttle is at WOT about the time the clutch is fully depressed. I would be curious to see what a stock LT1 could do using this method.
2.2x is what that method gets ME, at my elevation. Doesn't work. That worked AWESOME for me when I had a Trans Am w/a 400/T5/3.45 gear. I could roll out 1.8x 60's with that combo on cheapy Cooper tires!
If I try that w/my LT1, it just doesn't GO. It works for you b/c of these two reasons:
I've hit a 1.86 60', but my car is not stock. I launch off idle, rolling into the throttle as I slowly release the clutch. The throttle is at WOT about the time the clutch is fully depressed. I would be curious to see what a stock LT1 could do using this method.
I launch very close to that except I hold Rev's at 4K, clutch in. As I am releasing the clutch I feed throttle. Smoothly, and quickly, might take a second, I put the throttle to the floor and continue to release the clutch. When the clutch is fully engaged I'm at WOT.
I need to perfect this a bit more but its working pretty good so far. I'm getting enough traction on a prepped surface and street tires, I need to do it faster. I think the car will take WOT sooner. We'll see.
not saying this to start a fight, but I would like to see this compared to a stock L98
It's hard to find STOCK L98 numbers...I've looked. I think that's b/c when L98's were out and new/stock, Chassis dyno access didn't exist or was very expensive. Now that it's readily available, most L98's aren't stock or STOCK ones are owned by people who don't do things w/their cars (like put 'em on a dyno).
I did the Kart yesterday, to establish a baseline before I start all my sick mods! Now, since I have 20 other interests that consume money, it may take decade for the "sick mods" to happen...but I tell ya...they're coming!
For context here are the engine's mods/stats at this point: *Sludged up, oil burning, neglected, 125k mile 1989 L98. *No air filter *Dual exhaust from down pipes back, no cats, straight through mufflers * Frisbee, smog pump and AC removed (BIG power here, folks!) *Advanced timing (turned the distributor) *5 junk yard Buick 3800 injectors and 3 original injectors
With those wicked bad assed mods done to the engine, it put down some BIG numbers! Joe Nova had better look out!
The final part that was funny was the high end of the test: The op asked where to terminate the test? "Does it have a rev limiter?" I told him "no", that the factory redline for an '89 was 5500 RPM, so we should run it to that point, which he did. OMG...the segment of the test from 5000 to 5500 took an ETERNITY! That is where I thought the thing might actually throw a rod! The thing was just SCREAMING!! in what I would call "agony"....and barely, and I mean BARELY, accelerating the dyno at all. I seriously wondered if the thing would even GET to 5500 RPM...and I was legitimately concerned if it would do it before it blew up. Talk about NO top end power at all. During the first pull the dyno op hit the throttle, and like I said, it pulled cleanly from idle....but when it got above ~5 k and it was just screaming it's guts out, he looked up at me with this look on his face, as if to say, "You sure we should keep going!?" I wondered, myself!
Finally, I believe the '89 is rated it's 245 chp at 4500 RPM, but interestingly this engine was done by 4200. IDK why, but that's what it did.
Here is the LT1 graph again for comparison. Note: unlike the L98 above, the LT1 is box stock, right down to the mufflers and everything. Note that I started both cars at a very low RPM so as to see what the "Low end tq" actually is...and to compare them. I wanted to the pull to start at idle speed, which we/the car physically did, but in both cases, the op didn't hit the "go" button on the dyno computer until after the cars had passed 1000 RPM. Whatever the case there, you can get a good idea of both engines' low end tq...and everything else.
A funny thing: yesterday when I told the dyno op, that I wanted to start the pull below 1000 RPM, he balked and said that the engine would throw a rod. He expressed further concern about "bucking, lurching" and other dire behavior from the engine that might force him to abort the test. WTF, people? I told him that none of that was a concern and to do it anyway from below 1000. He did, and of course the engine didn't object at all.
Wish I could edit the original title of this thread though. :-/
I don’t think he is actively involved in C4’s anymore but I brought him up because of the subject matter although 6 six years ago... he was always a big believer in the flat torque curve on the LT1 cars....which they have ...proven over and over again by dyno testing like yours. Then the L98 torque monsters would come out and say they have more torque than the LT1 which they certainly don’t except maybe for a VERY short margin in the RPM zone....stock to stock ....but a boat guy was so amusing in his posts! Funny dude!!
Useful, meaningful post Tom! The LT1 is not showing much age!!
Wanted to add...this was my results on the dyno and track with a miniram equipped 85...is it safe to say the miniram is similar to the LT1 intake? Most would say they are similar in design. Where do you see a “loss in torque “ in this dyno graph???? Looks flat to me....And by the way...that same set up with the long runner Edelbrock TPI set up made less torque everywhere except around 3300 RPM. That graph is lost however but I built this car with every part so I know. Sold the car but will never forget the experience and what was learned. You don’t need to rev them to the moon like I see posted here all too often.
04-18-2013, 11:11 AM
During the first pull the dyno op hit the throttle, and like I said, it pulled cleanly from idle....but when it got above ~5 k and it was just screaming it's guts out, he looked up at me with this look on his face, as if to say, "You sure we should keep going!?" I wondered, myself!
I told him that none of that was a concern and to do it anyway from below 1000. He did, and of course the engine didn't object at all.
