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Discussion Starter #1
Well first thing I am going to say is that the BMR AWK will be going back in and these GM bushings will be thrown in the trash. My wheel hop last night was just as bad as when the car was stock while trying to heat up the tires. Now on the shifts the GM bushings seemed to work fine but from a stand still the BMR is a "way" better solution. My 60' times sucked A$$, excuse my words but I was not happy at all last night and still this morning can't wait to put the BMR back in.
I made 3 passes and my first one was the best but none of the runs made it into the 12's..:mad2: The second run was completely my fault as I missed third gear, It should have been a 12.8 run so that really bumbed me out..:bomb:
My next run I almost broke the car trying to heat the tires up. Nothing but wheel hop and as I was getting a little aggravated with the whole situation so I just hammered the gas to the line wheel hoping and the car felt like she would be joining Dan on a flat bed ride home. At that point, I really didn't care one way or the other. After that disappointing run I brought the car right to the air shack and brought the drag radials up from 17 pounds to 34 pounds for the ride home. I knew if I made another run she would not be any better and with my mood it was the best thing for the car to call it a night.
The part that really bothers me as that I had the wheel hop tamed to the point where I would say that it was gone. When you are thinking you are going to get a new personal best and then see one of your friends going home on a flat bed and you know that could be you the way the car is hopping it makes for a bad mood, atleast for me..:yup: Hey, that was a hell of a nice run on sentence, I made a whole paragraph one sentence long..:histeric:
I will add the time slips in a couple minutes..
I am car number 554

Bill
 

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Since I've installed the bushings the wheel hop has improved but I believe it has more to do with the hard a$$ Falkens I have on there than anything else. Sorry to hear about your night. I was looking forward to seeing some 12.8's as well.
 

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Discussion Starter #3
Thanks, the BMR will for sure be going back in..
One good thing, the mph is up.. She was making some power just couldn't get a nice 60' time..
Bill

Run 1... 13.058 at 111.95....


Run 2...missed third, should have been a 12.8 run.. 13.120 at 110.60


Run 3...Off throttle shifts.. 13.126 at 110.73
 

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Your mph puts you in the 12's if you can get a good launch. The cooler temps help with power but hurt with wheel hop also.IMO..
I went to Englistown last night, and it was closed due to rain. It must of rained earlier, when i got there everything was dry. I'll try next week.
On the way home I did get to show an M3 the V's B&B exhaust!
 

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That's crazy. At 112 MPH I would think you should be in the low-12s with a 2.051 60' time. I guess I naively assumed that similar 1/4-mile MPH and 60' times would always net you similar ETs even on different cars. I didn't think there was that much more to the equation. I thought that if you have the HP to move a vehicle to a particular MPH then the only other factor to determine ET is traction (60' time).

I'm amazed at the nice MPH you guys have and figured the relatively high ETs were due to the 60' time, but a 2.051 isn't really a bad time on street tires. In the GN, I can run mid-low 12s with 2.1xx 60' times and trapping 109-112 MPH (if I turn the boost down ;). But my 1/8th mile times are 8.0 @ 88-90 MPH on those runs. The only thing I can think of is that you're spinning beyond the 60' mark? Based on my (perhaps limited) experience, you guys all have easy 12-second ETs with your trap speeds. I'm baffled as to why it's such a struggle, especially if you're putting up 2.0x 60' times.

Your getting closer though, and your 112 MPH is impressive.

Jim
 

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Jimmy, Perhaps it is also the loss of traction shifting into 2nd. Third is not that bad. I have yet to go to the drag strip, but I can tell you that on the street if I redline 1st and grab second hard, I am gettting a little sideways, and I'm sure that is also scrubbing off a few tenths. Hence the 13 second runs with 110 mph speeds. The car has the ability, just traction problems. They should have made the V with 275's in the rear. Also launching a 400 hp car with a manual takes a lot of practice.
Example. Last night I went heads up 3 times with a new M3 with a Remus exhaust. The car looked sharp, and they guy driving could not have been older than 21. He was game for some racing. I figured this to be a good judge of the cars because we were both ready to play.
1st 2 runs we left from a light, and he launched his car better than me. I was overzealous and spinning as he spun a little and moved a car and 1/2 in front. As soon as I hooked up I gained back the 1/2 car and when I went into second I started to pull him in fast. Unfortunately we had to slow down before grabbing third. The next time we had an even launch and I pulled away immediately and he had no power to pull on me, that was over after second gear.
The final run was a from second gear roll at about 30 mph. We were both in 2nd. I started pulling on him right away,right before grabbing third I was already 1 car ahead. After third He faded away.
It was cool and the guy was cool. Now, in all fairness my car is not completely stock. His was as far as I'm concerened. His exhaust did not sound that great and the sound of the B&B was over powering his.
All in all if we ran a 1/4 mile I'm sure the m3 can pull out of the hole quicker, but the way i pulled him in, the v will smoke the m3 in the 1/4. Probably would pull him in by the time you shift into 3rd gear and pass right by.
I think my V should pull a 12sec. run. Now, I hope it doesn't rain next week.
 

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Actually, there is no difference between the GM/Specter/BMR connections other than that cross bar.
The GM rings are shallow , the Specters are deeper the BMR's are metal instead of plastic but in the end all they do is lock up the cradle bushings. The 'chine' walk that the CTSV does is due to the IRS set up. I have always thought that the right spring/shock combo is the only thing that will 'truly' get rid of the hop short of a straight axle. The guys that get good launches are just lucky. Unfortunately its inconsistant.
Just my wag!:annoyed:
 

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If your running F1's, don't even bother trying to heat them up. Slicks, or Nitto DR's are the only tires that will react to heating them up. Lower your tire pressure to 19psi and no burn out. You may not have a rear left when you are done, but you will stick better than doing a burnout.
 

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The 60's and traps are great, even in the 1/8th. I would speculate that there is a loss of traction and/or slow shifting. Not that I'm better or something, but I love those traps. Do you guys powershift?
 

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lasstss said:
Actually, there is no difference between the GM/Specter/BMR connections other than that cross bar.
The GM rings are shallow , the Specters are deeper the BMR's are metal instead of plastic but in the end all they do is lock up the cradle bushings. The 'chine' walk that the CTSV does is due to the IRS set up. I have always thought that the right spring/shock combo is the only thing that will 'tuly' get rid of the hop short of a straight axle. The guys that get good launches are just lucky. Unfortunately its inconsistant.
Just my wag!:annoyed:
Yeah, they did not come up with a combo that could launch well, ride well, and handle well. It is all about sweating the details and they dropped the ball here. A lot of it has to do with rear suspension design. Certain designs do a much better job of transferring torque.

It has nothing to do with IRS. SL65s launch with over 700 lb-ft of torque and IRS.
 

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Discussion Starter #13
CTS-VPaco said:
The 60's and traps are great, even in the 1/8th. I would speculate that there is a loss of traction and/or slow shifting. Not that I'm better or something, but I love those traps. Do you guys powershift?
The only run that I did not power shift was the last run, since the run before I missed 3rd. I was ready to go home and wasn't even into the last run after dealing with all the wheel hop she has again. I shift pretty fast, not saying I am the fastest on the forum but I would think in the top few. I have always been known for my quick shifts so that isn't the problem with the times. I will get a video made from the inside showing a run with me shifting. Maybe I have gone slow in my years and not as quick as I used to be 15 to 20 years ago.. haha

Bill
 

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MCaesar said:
Yeah, they did not come up with a combo that could launch well, ride well, and handle well. It is all about sweating the details and they dropped the ball here. A lot of it has to do with rear suspension design. Certain designs do a much better job of transferring torque.

It has nothing to do with IRS. SL65s launch with over 700 lb-ft of torque and IRS.
That is because its not the V's IRS. Even the Vetts get wheel hop on occasion. The new mustangs get it also. Its more pronounced on an IRS than a straight axle. If the IRS system was better they would use it on drag cars. They dont because its not stable. Just great for turns.
 

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Discussion Starter #15
The only 2 things that were changed along with the new diff were the BMR AWK and the BMR pinion support was taken off. We left the BMR toe rods and trailing arms on and the GM bushings were installed. The Cadillac tech that worked on my car said he liked the BMR rings and caps better. The GM bushings seem to be a little loose compared to the BMR parts. I checked the torque on them a couple times and they are on the money. I think they are crap, BMR rings and diff support will be back in after the 06 unit goes in. I just will have to make that happen a little sooner than later.

Bill
 
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