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.
Went to the annual SRK rental at US41 and struggled all day to get the car moving. Ended up putting 60 pounds worth of dumbbells in the storage boxes to get it to move. Last fall it went 10.8x@128 at MIR this spring after H/C/I it went 10.62@134.8. I had a best 1/8 of 6.80@105.7 so it is capable of a solid 135 trap. car weighed a tick over 3200.
10.62 @134...doesn't add up well.
Your HP computed from your vehicle ET is 478.45 rear wheel HP and 531.62 flywheel HP.
Your HP computed from your vehicle MPH is 545.90 rear wheel HP and 606.55 flywheel HP
Mid 9's may be a bit of a stretch.... (9.7 to 9.9 more likely) depending on DA also, with that MPH and weight (3230# ?)
Your vette is awesome Phil. Looking at the fastest six speed list(which both ddnspider & lazer are on) it gives a good aspect. To get to a nine with 135-138 mph the car would probably have to 60' a 1.3x or close to it.
Last edited by SoFla01SSLookinstok; 05-17-2019 at 08:45 PM.
For an automatic car, most of what it takes to achieve that 9.85 level of efficiency comes from finding a proper torque converter that slips just enough to let the engine make the most of it's power band. For a manual trans car, the equivalent to the right torque converter is controlling the clutch hit so that it doesn't cause bog, spin, or broken parts. All three of those things will reduce your fun factor, and all three are caused by a clutch that's allowed to hit too hard. Don't tune the chassis to work with a clutch that hits too hard, you will be moving in the wrong direction. Fix the clutch situation first, everything else will fall in line much easier.
Grant, I actually have your clutch tamer to install. Hopefully get that done next weekend. I have a twin carbon RPS with Tilton hydraulics. Love this clutch. I was hitting the tires to hard and spinning to the 1.5 60’
Please, don't take this the wrong way guys. Not negative. Seriously, hitting a nine second quarter mile, in an M6, is not as easy as it seems to be portrayed. Last car, in my experience, was trapping 140+mph & hitting 10.0 with 1.5x 60'. He got a 1.4x 60', with 140+mph, & got his first nine slip. He turned it up a bit, as by higher mph, & could get a nine with a 1.5 60'. And the clutch tamer is probably the best way to launch the hardest. Just don't be surprised if your clutch burns out on you after using too much. Unless I'm mistaken.
Every car is different. I'd say focus on low tens before thinking about nines.
Props for posting up. I think it is expected to take a while longer to hone in the setup and get the most out of it, keep your spirits high.
Phil how close to redline are you running through the traps? Also what is your max mph for 4th?
I think one of the best comparisons for this situation would be gary's bolt on c6z running 9.97 @ 137.7
I found the breakdown of the slip
Breakdown of pass. 60'.......1.366 330'.....4.119 660'.....6.378 MPH....109.17 1000'....8.331 1/4......9.973 MPH....137.72
Similar rear gear ratio, 4:10 vs 4:11s, similar chassis, obviously both all motor stick shift cars, both running RPS clutches. Biggest difference being running at atco, maybe bogarts, Gary running a 15 or 16" and probably a wider tire. Phil's car is making more power than a bolt on c6z, or about the same?
A slightly less comparable setup, Cartek trans am, SBE ls1 going 1.43 60' and 10.32 @ 132
And of course two of my favorite cam only stick shift f bodies.. both weighing 100-200lbs less and single disc clutches
I've been looking at the hydraulic clutch systems to assist launching. What're the advantages/differences between the clutch tamer unit vs something like these?
I've been looking at the hydraulic clutch systems to assist launching. What're the advantages/differences between the clutch tamer unit vs something like these?
The upper unit is similar to the Magnus Launch Control, basically an adjustable in-line restriction with a solenoid bypass. The downside to that style system is it forces you to compromise reaction time vs ET, as engagement travel at the TOB is delayed from the instant that you pull your foot from the pedal. Basically it adds time between releasing the pedal with your foot and achieving an affective amount of clutch engagement. It takes a lot of restriction to get your best ET, but the more restriction you add the more delayed an effective level of clutch engagement becomes. The bypass solenoid usually functions to make the system active on launch only.
The lower unit is the Clutch Masters Flow Control Valve, also an in-line fluid return restriction except it is active for both the launch and all the shifts.
You can get away with small amounts of simple in-line restriction without much trouble. The problem when using it for drag racing is that clutch master cylinders typically use a cup style seal. When you restrict fluid return, the MC's internal return spring causes excess fluid to be drawn past that cup style seal. Not a problem during casual driving, as the excess fluid has time to return to the reservoir before the next shift. But when clutch cycles come in quick succession, that excess fluid does not have time to return which causes an increasing pump-up effect that messes with driver coordination. Driver thinks he missed a shift, but what actually happened was the pump-up caused over-stroking of the slave, which in turn caused a delay in the clutch grabbing after the shift. Many oem's actually use a "clutch delay valve", basically a one-way restriction to slow clutch engagement for the purpose of protecting the drivetrain. Lots of u-tube videos out there dedicated to removing them. The Magnus design minimizes the pump-up effect by adding a solenoid bypass parallel to the in-line restriction, making the restriction path active only during launch. The Clutch Masters design does not have a bypass, so it suffers from pump-up when shifts come in quick succession.
My HitMaster valve was originally designed as an improvement over the Magnus design, as it allows an adjustable volume of fluid to return freely before the restriction becomes effective. You could dial in all the fluid restriction you wanted without hurting reaction time, as the restriction path only became active after the clutch hit. We have since found that it works even better when you eliminate the restriction path to get a stepped engagement "curve". That stepped curve allows the clutch to hit deeper into the sweet spot, without blowing thru it prematurely, also allows getting to full clutch torque capacity much quicker (that last part is important with power adders ). Our HitMaster system's timer completely releases flow after it times out, so not only does that give excess fluid more time to return to the reservoir, but that fluid return then also gets an assist from the PP's spring acting against the throwout bearing. Very quick return of excess fluid, result is no pump-up effect.
The original ClutchTamer being attached to the pedal prevents the MC's return spring from drawing excess fluid past the seal, so no pump-up effect at all when using it. Also no increase in reaction time, as the pedal returns freely up to it's adjustable hit point. It's only after the pedal reaches the hit point that pedal return becomes delayed, the original 'tamer is also active on launch + shifts.
Grant
Last edited by weedburner; 06-13-2019 at 06:54 PM.
Awesome post Grant! I also see you have an rx7. I have a swapped '94. I've been able to ride the clutch to a 1.74 on R-comp radials, but have never had a drag tire on it or any luck putting more power down than that. It isn't a drag car, but I like to take it out every once in a while to surprise some people. I've been 11.18 @127, and fastest of 129.85 in the quarter in complete street trim.
I'm building an LS7 and will need some help with the extra power if I'll be hitting my 9 second goal. I like the looks of the original clutchtamer if I can fit it under the dash! Much easier install in an already very space constrained vehicle..
Lazer, can't wait to see you get more seat time in this thing.
05-17-2019, 09:48 AM
**** poor track results but is what it is 
). Our HitMaster system's timer completely releases flow after it times out, so not only does that give excess fluid more time to return to the reservoir, but that fluid return then also gets an assist from the PP's spring acting against the throwout bearing. Very quick return of excess fluid, result is no pump-up effect.