[ZR1] Do you guys want to know the secret inside the last two 1/4 mile record holding ZR1s?
01-13-2012, 12:47 PM
#21
Le Mans Master
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Kyle, you are correct in the fact that the 60's haven't picked up on either of our passes from both trannies, but the overall 1/4 picked up with no other changes to the car or tune at all. Went from a 9.93 to a 9.68 just changing the trans. The fact is with the amount of power being produced it will be hard to dip in the 1.4/5's without the wheel spin. Next time out we think it will go a 1.5 in the 60', it just takes time to find the right spot for the clutch to keep it from spinning. Also the Spec clutch in the car is an instant grab and is harder to control the wheel spin. 1.6 = 9.68, 1.5 would = ? and that is the mark I would like the car to shoot for.
Andrew
Andrew
As for the Spec, we have seen many having a difficult time trying to induce slip. At your power level, you need the clutch to hold but some slip off the line is a wonderful thing. It's a hard combo to find. We found that the RPS BC2 can do a substantial amount.
01-13-2012, 01:02 PM
#23
Instructor
Just wanted to agree that with a trans ratio change there should be a gain. If it works on paper for us, we tend to believe it. It would be nice to prove the theory as we have proven them in the past. Perhaps we could take a ZR1, tune it, change the trans and clutch, put on my drag pack and see what happens. I can foresee 60's in the 1.3s on a good track with the right driver. 
Hell if someone could get my car to go 1.3 to the 60', mine should go low 9's. But I just don't believe it has it in it with the clutch that I have unless I do a spindle and brake swap and put slicks on it.
01-13-2012, 01:06 PM
#24
Former Vendor
Thread Starter
01-13-2012, 01:22 PM
#25
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Call me crazy, but I'd like to see how our 11" single would hold up...It's held 1111 to the tire and been 9.7 on a low 1.4 in a 3700lb pig
01-13-2012, 01:23 PM
#26
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The RPM 4.10s really help.
http://www.youtube.com/watch?v=VnBdxvLyULE
Bruce wanted to be in this too. I had to add the GoPro vid with Bruce.
http://www.youtube.com/watch?v=xwuv2zhqVuA
Last edited by GARY2004Z06; 01-13-2012 at 05:03 PM. Reason: Bruce needs to feel the love.
01-13-2012, 01:27 PM
#27
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01-13-2012, 03:12 PM
#28
Melting Slicks
Thanks for posting up Andrew. I was about to contact you for some specifics so I could post a fully educated reply.
The ET gains by swapping to the 2.66 unit aren't found in the 60ft. The gains are down track in 2nd and 3rd gear. It takes a skilled driver to launch any ZR1 and that is no different when swapping to the 2.66 unit. If you are skilled enough to pull 1.5 60fts you can launch a 2.66 geared car equally as well while achieving a quicker quarter mile ET.
I know for a fact that the 2.66 gearing makes these cars quicker. Both the LPE ZR1 and the LMR ZR1 were stuck at a specific ET. As soon as they installed our 2.66 geared unit with no other modifications and both cars picked up almost 3 tenths.
The ET gains by swapping to the 2.66 unit aren't found in the 60ft. The gains are down track in 2nd and 3rd gear. It takes a skilled driver to launch any ZR1 and that is no different when swapping to the 2.66 unit. If you are skilled enough to pull 1.5 60fts you can launch a 2.66 geared car equally as well while achieving a quicker quarter mile ET.
I know for a fact that the 2.66 gearing makes these cars quicker. Both the LPE ZR1 and the LMR ZR1 were stuck at a specific ET. As soon as they installed our 2.66 geared unit with no other modifications and both cars picked up almost 3 tenths.
01-13-2012, 03:36 PM
#29
Former Vendor
Thread Starter
No we never did get the MZ6 trans in the car. We have been very busy with a ton of projects this year. The ZR1 got raced at LS Fest but didn't get much love other than that. We hope to get it out quite a bit more this season.
01-13-2012, 07:02 PM
#30
Playing the devils advocate, more power doesn't automatically produce a faster time you have to be able to harness it of course. The fact that the zr1 has such a tall first gear makes it harder to launch as it makes the clutch slip that much more crucial to get a good 60' as I know you can attest to. The steeper gear shortens that window of trying to match wheel speed to rpm and will also help lengthen clutch life imho.
The LPE car was run with a stock clutch and that wouldn't allow additional RPM without slipping. After the gear swap, you could bog the car slightly and not have the thing fall on it's face. That brought the 9.8 pass. Even with the shorter low gears in the transmission, the best results were with a quicker release and letting the torque pull the car back. More RPM / More feathering the clutch was too much for the stock ZR1 clutch in the LPE car.
Scott
Now with a better clutch allowing more aggressive launches... I have no doubt that car could have picked up at least a few tenths..
01-14-2012, 06:41 PM
#33
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Thanks for posting up Andrew. I was about to contact you for some specifics so I could post a fully educated reply.
The ET gains by swapping to the 2.66 unit aren't found in the 60ft. The gains are down track in 2nd and 3rd gear. It takes a skilled driver to launch any ZR1 and that is no different when swapping to the 2.66 unit. If you are skilled enough to pull 1.5 60fts you can launch a 2.66 geared car equally as well while achieving a quicker quarter mile ET.
I know for a fact that the 2.66 gearing makes these cars quicker. Both the LPE ZR1 and the LMR ZR1 were stuck at a specific ET. As soon as they installed our 2.66 geared unit with no other modifications and both cars picked up almost 3 tenths.
The ET gains by swapping to the 2.66 unit aren't found in the 60ft. The gains are down track in 2nd and 3rd gear. It takes a skilled driver to launch any ZR1 and that is no different when swapping to the 2.66 unit. If you are skilled enough to pull 1.5 60fts you can launch a 2.66 geared car equally as well while achieving a quicker quarter mile ET.
I know for a fact that the 2.66 gearing makes these cars quicker. Both the LPE ZR1 and the LMR ZR1 were stuck at a specific ET. As soon as they installed our 2.66 geared unit with no other modifications and both cars picked up almost 3 tenths.
So how much of the gain in the car do you attribute to the Gear swap VS the -1200 DA?
Your talking about a gain down the track that was probably a function of the DA?
01-15-2012, 09:00 AM
#34
Drifting
What clutch is in the lpe car?
That run was made in a minimum of positive 2500 DA (+4000 by the weather details shown in your video)
Correcting the two passes to 0 DA the 10.03 in muncie was at least equal or even a better pass then the 9.81 at MIR
Im not saying the different first gear isnt rite in some applications, im just saying your blanket statement of swap the gear for signifigant gains is not 100% accurate.
Last edited by Kyle Lemish; 01-15-2012 at 09:08 AM.
01-15-2012, 05:57 PM
#35
With the stock gears, we had to leave with a lot of RPM and it really stressed the clutch. Remarkably, even after the aggressive launches the clutch continued to perform going down the track. BUT, with the stock transmission gears the only choice was a big bog out of the hole or letting clutch SLIP and net a modest high 1.5-1.6 60 foot.
IMO, the best solution is a slightly stronger clutch that will allow the driver to progressively engage AND the shorter transmission gears the let the car recover quickly. Given a choice of one or the other, I'd go with the transmission gears since the LS9 clutch is so nice to drive regardless of it's limitations for aggressive launches on sticky tires.
Scott
01-15-2012, 07:38 PM
#36
Drifting
The LPE car ran the stock LS9 clutch.. If memory serves me right, the 10.03 run in Muncie was with stock gears. Those runs were the motivation to try a transmission gear change to keep the awesome street manners of the stock clutch but push the car into the 9's.
With the stock gears, we had to leave with a lot of RPM and it really stressed the clutch. Remarkably, even after the aggressive launches the clutch continued to perform going down the track. BUT, with the stock transmission gears the only choice was a big bog out of the hole or letting clutch SLIP and net a modest high 1.5-1.6 60 foot.
IMO, the best solution is a slightly stronger clutch that will allow the driver to progressively engage AND the shorter transmission gears the let the car recover quickly. Given a choice of one or the other, I'd go with the transmission gears since the LS9 clutch is so nice to drive regardless of it's limitations for aggressive launches on sticky tires.
Scott
With the stock gears, we had to leave with a lot of RPM and it really stressed the clutch. Remarkably, even after the aggressive launches the clutch continued to perform going down the track. BUT, with the stock transmission gears the only choice was a big bog out of the hole or letting clutch SLIP and net a modest high 1.5-1.6 60 foot.
IMO, the best solution is a slightly stronger clutch that will allow the driver to progressively engage AND the shorter transmission gears the let the car recover quickly. Given a choice of one or the other, I'd go with the transmission gears since the LS9 clutch is so nice to drive regardless of it's limitations for aggressive launches on sticky tires.
Scott
I agree with with you.....and that car has proved just how great the ZR1 with just a few bolt-on's can run!
I am a fan of RPM's work too, just didn't really like the way this thread started by saying it was the secret to the success of these cars was the gear swap. It may have aided in the success but it wasnt exactly the key. They also have no data to support what their claiming that simply swap their gear and a ZR1 will pick up .3 at the 1/4 track.
The more passes I make in the stock ZR1 the more I think that the stock first gear is well suited to the car in stock trim.
