New stock longblock Supra PB

Went to the Fayetteville drag strip Sunday for some shakedown passes in preparation for the Dragging Rights 5/6 speed shootout next month at Rockingham. It ended being a lot warmer than I was hoping/anticipating – mid 70’s or so. I managed a personal best on an otherwise mediocre run, which ended up being one of only 2 complete passes due to issues.



Video:




http://www.youtube.com/watch?v=4-AmjSR0feQ






Pertinent mods:

RPS turbo kit w/ original 3” downpipe & recirculated wastegate
ITS 74mm .81ar turbo
RKS Powersystems fuel kit
HKS Carbon Ti exhaust
Greddy 3-Row FMIC
VPC/SAFCII/Gforce ECU
Rush Racing antilag
RPS billet carbon/carbon clutch
TRD diff
SP driveshaft
TRD engine and trans mounts
Bone stock original longblock
28x10.5x15S on Weld Draglites
HKS Hipermax II coilovers
Full weight + w/ big stereo in the hatch

First pass I had too much tire pressure and not enough of burnout on the brand new Mickeys, so I blew the tires away, got sideways and had to pedal it to a 10.8 @ 138.8MPH with laughable 60’. Overall the car felt very stable and I noticed no difference in stopping power with the NA brakes, so it was a decent first pass all things considered. Checked the tires for rubbing and all looked good so I dropped the tire pressure down, loosened the front coilovers 2 clicks and went back out.

2nd pass I did a little longer burnout and rolled out of it until the tires grabbed hard. Got on the 2-step and dropped the clutch and the car hooked HARD and then a moderate bog – I knew this was going to be a great pass. Nailed the 1-2 shift, banged into 3rd the car instantly fell on its face and bucked and stuttered. WTF!? I thought the engine let go so I clutch in and it dropped down to idle fine, felt and sounded ok when I revved, etc.. so I turned off the track and it seemed to drive fine. I ended up with a 1.54 60’ and a 4.34 330’ so even with the bog it was leading up to a great pass… I poked around the car for about an hour trying to figure what the issue was and couldn’t find anything wrong. I know I’m at the very edge of the 75lb injectors so I thought maybe I had hit fuel cut since I was adding +45% in some spots on the SAFC so I bumped up the static fuel pressure from 46 to 48psi and took 5% out of the SAFC. The car drove fine and sounded fine around the pits so I did a test pass and just walked it out and hit it 2nd and 3rd gear and it seemed fine so I lined back up.

3rd pass my 2-step wouldn’t come online after I staged due to my dumbass disconnecting the arming switch accidently. I was certain I was going to bog so I revved the piss out of it and dropped the clutch and surprisingly spun hard out of the hole, but not hard enough to smack the limiter. The car got a little sideways and came out of the groove but I recovered and banged into 2nd. The rest of the pass was pretty uneventful though I short-shifted the 2-3 shift, which is a habit I’ve been trying to break. I ended up with a new best:

60’ 1.667
330’ 4.522
1/8 6.782
MPH 110.86
1000 none
1/4 10.363
MPH 139.53

Coulda, woulda, shoulda, but had I had the short time from my 2nd pass that would’ve easily been at least a 10.1 pass.


The next several passes were all wasted as the car did the shit all over itself thing again when shifting into 3rd gear. It happened liked clockwork each time and has me baffled. It feels like hitting fuel cut/speed cut and you can hear the car completely fall out. I have a few weeks to get all of the kinks worked out, so hopefully I will make a good showing at Dragging Rights in Nov.! I’ve also got some suspension tweaking to do, and I need to raise my launch RPM a little to keep from bogging now that I’ve got a few heat cycles on the tires. Also going to go to a bigger injector as I am completely out of fuel at 29ish psi.

on the other forum, you mentioned walbros struggling above 80 psi. Is that based on the flow map or anecdotal evidence? I ask because my base fuel pressure is 50 psi and I've run as high as 33.5 psi ... so 83.5 psi line pressure.

Damn... You were moving out. I hope you get the falling flat on its face issue and set some even more badass times ;)

Adam -- Mostly anecdotal. The Walbros have an internal relief valve that cracks at around 82-85psi, so I prefer to keep them below that threshold since I don't have an in-cabin FP gauge.



Doc -- The car will go 9's soon. ;)

A clean run will easily be in the 9's ;) It still amazes me how right Toyota got the Supra

very impressive!

I love the commentator on your first run.

-John

Adding 85lb injectors, TiAl Q BOV and stepping down to a cooler plug in preparation for Dragging Rights. Weather should be chilly and the track will sticky fo sho! 6000RPM and 25-30psi off the 2-step should get me moving. :teu42:

Good luck!!! I'll pray for your axles and hope to see vids of a new PB:)

Launching harder should actually help take some of the stress of the drivetrain, because it lets the tires do all the work. The problem I was having after I got a few passes/heat cycles on the tires was they were dead hooking and causing a hard bog, which is much harder on parts than a controlled spin. I was spinning for the first 10' or so and then the tires would hook hard and the car would fall on it's face; what I'm looking for is a good controlled spin for the first 20-30' to keep the RPM's on boil and get the car moving before it fully hooks. Even my 1.5 60' was with a bit of a bog -- if you watch the video the car leaves hard and the noses over about 20' out. If I would have left a little harder it would've powered through and it likely would've been down in the 1.4 range, which is what I'm looking for to run a 9 as-is.

That said... Anything can happen when racing! If anything is going to break at this point, it's likely to be the axles -- they've seen a lot of wheel hop/abuse from my BPU And drag radial days. The TRD diff and chromoly driveshaft are virtually indestructible, so they axles will be the fuse if something has to give.

When are you installing the injectors and bov? Curious to hear if it fixes your issues. Will you be upping the boost since you have more fuel? or will it be basically fruitless because of your downpipe restriction?

I'll probably have the car buttoned up next weekend. The bov may not be on until the week after depending on when it arrives. I'll be giving it a pretty thorough road test prior to heading to the track. If the issue is not resolved I'll be completely baffled; I'm fairly certain it's fuel cut and/or the surge from the insufficient BOV is freaking out the VPC's MAP sensor. We'll see...

I'll definitely be turning up the boost now that I'll have enough injector to support it. The gains will be fairly minimal until I uncork the hot side, but it will still pick up a little power per psi.

Nice run, look forward to seeing more vids and faster times.

I got the car done this weekend and street tuned -- the Tial Q is LOUD at 32psi! The only thing left to do is tidy a few vacuum lines up and swap in the cooler plugs. In hindsight I should've just gotten the 95lb/1000cc injectors, though. I still need to keep the base FP bumped up a little to keep the a/f in check at high boost. It should be good for a safe 33-34 psi if my wastegate spring will let me get there. Looks like I'll be swapping injectors again when do either the downpipe and/or cams.... :Disdain:

You break? Havent posted in a month

Demanding update, Enquiring minds want to know.