Zombie

iTrader: (2)

It seems to me that most of the turbo cars MPH higher than me with similar ET's. I'm curious as to why my car only traps 134-136 but can ET 10.0-10.2. It's not like I cut great 60's. With a mid 1.6x 60' I'll typically run 10.2 @ 134. I'm not complaining, just curious as to why I see more cars running high 9's low 10's in the 138-142 range (autos not manuals) with better 60's than me. If I ever get a 9 sec pass I'll probably only trap 135-136 with a mid 1.4 60' (best 60' is 1.47).

I'm usually trapping 108-109 in the 1/8 with 6.38-6.5 ET's. My ET/MPH seems more in line for a car that cut's high 1.3 low 1.4 60's.

2001-WS6

It's going to be air... air... air... and bad heat vs good heat problems.

The only real differences in our cars with the ST80 were the air, front mount vs rear mount and the tunes. We'll say tires and the difference between 91 and 93 octane are minor. The more conservative runs were in the 15psi range for the 9.7-9.9 at 144mph for better comparisons on pump gas.

I've run a 9.4 at 149mph with the same turbo at 17-19psi. I've maxed out the hotside on the turbo. You've corrected some of that problem going to the bigger hotside now with the SX80.

Figure my local track is probably in the 500ft elevation and yours is closer to 2,000ft. Somone can take a stab at the impact that has with given air temps and power. You loose more heat in your setup for sure with the rear mount vs front mount but that's tough to quantify. Then figure 3-4mph speed loss for every 10 degree difference in air temps. My best passes were probably in the 75-80 degree range for air temps.

Somewhere in there is the 8-10mph that you are trying to tracking down.

Rick

mike13

iTrader: (27)

Could be your torque converter

MIGHTYMOUSE

iTrader: (59)

sounds to me like its a mix of a slower spooling turbo/ soft launch / too low a total gear ratio (60') and a generous rear tire for 100% traction (to get et back) rounded up with another dose of inefficiency in the form of too much gear/tire/ too lose a converter thru the traps.

last friday night pass of mine:

60: 1.553
330:4.164
1/8th: 6.305 at 118.55
1/4: 9.698 at 142.63

8psi launch about 4250 RPM
rolled out to 57% throttle coming to 100% at 2.2 seconds into the pass
maintained avg 12.7psi through the pass
IAT 63* avg
11.3 avg AFR
295/17" drag radials, 3.0 rear gear, pump gas and meth thru the cat-back

Considering thru the traps at only 5900 in third I'm pleased and look forward to full wick on this 91mm... hopefully it can get me the 165mph or so I have geared to target.

when i was building for 140mph i had the gear at 3.42.

for maximum acceleration the math says you want the highest total gear ratio you can put into the car and still get thru the traps in your 1:1 gear (along with the tightest converter you can get in the car that will still 60')

black98ws6ta

iTrader: (77)

Weird combo=weird results?

Post all the incrementals from a timeslip.

FANTAZ28

iTrader: (2)

gear ..gear..gear..gear...

gear, tire size and rpm go hand in hand with converter efficiency. call any converter company in the country.

Zombie

iTrader: (2)

60: 1.497
330: 4.145
1/8th: 6.389 at 109.13
1/4: 10.001 at 135.28

Up to the 1/8 we have similar times but look at the drastic difference in MPH. You obviously are making way more power than me as seen by the MPH difference. You pick up 23mph from 1/8th to 1/4 and I pick up 26mph which seems pretty normal for auto cars.

Converter is around 4-5% slip at 6800 rpms.

Tiago

iTrader: (27)

you picked up 109 to 135 though he is picking up from 118 to 142 much more top end.

How are you determining your converter slip?

black98ws6ta

iTrader: (77)

To me Mightys mph is alittle funny...my car trapped 118 and went 147 in the 1/4. Most cars around that hp level pickup almost 30 mph usually.

The rear mount c6 I built runs really close to what you do..I'm going to dig for its timeslip. I believe it went a 1.56...6.60@112....9.96@143.

Zombie

iTrader: (2)

My car typically picks up 26-28mph 1/8th to 1/4 which seems pretty normal from others times I've seen.

I think that 6.38 is a good ET for the 109.1 MPH considering the 1.49 60' Seems like most cars running in that ET/MPH range are in the 1.3 60' range. My 60's should improve with the cage, torque arm and faster spooling now. I went 1.62 60' spinning 60-80' out on a 5psi launch last time out (no cage and stock torque arm). When the track is prepped I should be able to launch at 10psi.

icicleboy

stick a pressure gauge in your exhaust just pre-turbo. With your valve it should spike high and then fall down as it opens. I'd like to know what it settles at through the back half of the run. This WILL tell you a lot about your housing/wheel combination. You could be out of turbine, or compressor. When going for power that makes 140mph traps your PR shouldn't be higher than 1.5:1 or so.

hellbents10

iTrader: (10)

Dave just went out with the GTO a couple weeks ago.

Stock 05' GTO 4050lbs with driver, 4l80e, 3600 stall PI, stock rear 3.4x gear. 275/40/17 MT ET Street Raidals. On E85 with a stock long block LQ9 at 19psi. S374 turbo, 83mm turbine wheel 1.1 a/r.

3psi on the launch.

IAT at start through the A2A was 80 at the end it was 150.

Locked the converter in 2nd at 55mph and let it eat through the traps.

60ft 1.5293
330ft 4.2321
1/8 mile 6.45
1/8 mph 111.96
1000 ft 8.3332
1000ft MPH 130
1/4 ET 9.9232
1/4 Mile 141.43 MPH

MY99TAWS6

iTrader: (3)

Mighty few questions for you..
You are still running 4l80e? and similar stall to my py3400e?
So you don't lock the stock ,yank said not to at my power level.
Are you on transbrake or foot braking? You use two step to build boost ?
Also your tires are drag radial not et street radial?
Do you run these same tires as your daily street tires?
Are you ramping by gear ,rpm ,time at track or on street?

MIGHTYMOUSE

iTrader: (59)

i am ramping by my right foot as it feels right to me.

i dont think im making much more top end power, it made 691rw unlocked like that (exactly) thru the catback and etc. the 118 at the 1/8 comes from better acceleration due to better spool/gear/tire/converter

increasing less up top is a reflection of the low boost and that i was allready making good mph at 1/8 so harder to add to it.

NicD

iTrader: (7)

Others have said it but it's what I think as well... 2.75 rear gear, rear mount, it all leads to efficiency losses and putting down the power in the best fashion.

MY99TAWS6

iTrader: (3)

Ok still want to clarify .Mickey has drag radial with no tread at all just their slick with radial construction. Then they have the et street radial which has tread on it.
http://www.mickeythompsontires.com/strip.php
So you have the slicks that are radials or the et street radials that many people still call drag radial.

Zombie

iTrader: (2)

So having a goofy gearing / trans setup means I can run good ETs with low mph? That seems odd.

I'm gonna try a set of some 3.25 gears next and see what kind of difference it makes. They are tolerable on the highway and will let me go 65 @ 2600. If I run .3 faster then they'll stay in, if not the 2.75's will go back in. Should be a good experiment. 3.25's will put me into 3rd right at the 1/8 shifting at 6400 rpms.

Sluggish

iTrader: (10)

Why don't you get a torque arm next,there only around $400.

Zombie

iTrader: (2)

Because they are $400 and I'm tired of spending way too much on car **** this year already. Next up $1600 for my clutch and install. Got a fuel system $2200 in a box that needs installed, need a new windshield, spent another $2400 for all my new piping and cage install. I think you get the picture. Next year. Gears might even wait until next year due to money.

code4

iTrader: (30)

I run 2.75's on a 28" tire. I have run as quick as 6.1 in the 1/8th but my best 1/4 is high nines. I can feel it fall on it's face when i shift into 3rd. It's lilke going through the traps in overdrive.

I don't want to change it though as my car's primary duty is transportation not racing.
I'm not legal to go single digits either.