I'm glad you got the suspension straightened out. Your car should be a lot safer and easier to drive now.

 

Congrats did you leave on more?

 

Roughly 6-7 lbs both times. Turned 2 step up from 3800 to 4300 the first pass that got me the 1.36 60' and spun after. Back down to 4000 the second pass. Not sure if the spinning the first run was due to bad track or too much power too quickly. I'm guessing it was track I'll turn it back up next outing.

 

Very nice. 1.25 and maybe dip into the 8.5's?

 

Went a little faster last night. Turned the 2 step up to 4400 spun right after the hit first run.

Dropped 6* out of it right after the hit and ramped it back in over 2 seconds. Seemed to work really well.

8.70 @ 159

 

Congratulations on the faster time. This thread never fails to deliver. Keep up the bad *** work

 

 

Congrats!

 

Awesome! Congrats.

 

Just reread this whole thread. Awesome journey.

 

Thanks!

Threw on some 275's and dropped the suspension/spring perches as low as they would go... Car sits almost level now. Looks much better I think.

After a night of cussing and 6 passes I finally dialed the power back enough for these 275's. Last pass of the night I managed a...

1.38 60'
5.67 @ 124 1/8th
8.81 @ 154 1/4.

Odd thing is i'm at the same boost I was at last outing where I trapped 160. Not sure where the 6mph went but I want it back! I added a degree of timing and didn't pick up any so I dropped it back down to 20lbs and 14*. Tried 21-23lbs and didn't go any faster. Somethings weird...

To be continued...

 

275 tire abuse! Last one is the 1.38. Tires always hooked initially, then spun 10-20ft out. Dialed power WAY back to keep traction. 4lb launch pulling 10* out over 3 seconds. Also 80% boost ramp rate over 3 seconds.

 

Loosen up the rebound on the rear shocks if you can. Might be able to hold the power a little better.

 

Big changes, slow progress…

Always though right at the end of the quarter my car nosed over a tad. Crossing the traps around 6200 at 159 with a 30” tire. I threw on some 275’s to play in the small tire class and can now confirmed that the engine is done around 6k… Lost about 5mph going ot the 275’s. Car just hangs and quits making power around 6000rpm. Fuel is there, back pressure is fine, IAT’s aren’t high. So I looked at the valve train first.

Pulled and tested PAC 1518 my valve springs. (rated at .650 lift) Even shimmed them a little… I’m at 150ish closed and 400ish open. Should be fine for my 224/224 .612 lift cam. Only want 6500ish RPM anyway… Used the fancy DIY scales Aknovaman built for me to measure spring pressures. Worked great!





So moving on to the next guess… Figure maybe the turbo is running out of steam… ?

Bought VS racings Billet S480 clone for $790. Was hoping it would drop right in my T4 housing, but apparently the china S400’s have different CHRA dimensions than the standard S400 CHRA? So I bit the bullet and started the cutting the frame until the huge T6 1.32 housing fit. Boxed in the area I cut out and now I’m waiting on a T6 flange to show up. Hope to have it in for an event this weekend. Always wished I went T6 anyway… figure now is my chance. Will be a good comparison anyway…

Measured the inducer hub to blade tip length between my old Billet 76mm and the new 80mm.
30.48mm vs 27.25. So a 3.23 mm difference. Not a huge difference overall on the compressor alone.

Also cut off the goofy T6 Borg exhaust flange and welded on a standard 4” Vband.


Mandatory turbo next to a beer pic…










1.25 T4 next to the 1.32 T6. The T6 is huge!



Can see the ID of the T4 housing VS the T6. Not sure if my CHRA was turned down when I sent it to forced inductions or what. Though he only machined the housing for the larger 87/96 wheel but I could be wrong.

T4



T6




Cut the Flange off…



Beveled it a bit and dropped the 4” Vband on. Welded inside and out. Also threw it in the oven on 500* before and after the weld and peened the crap out of the welds. Hope they hold!

 

Finally go the S480 installed, what a pain!

Anyway I got a few street pulls. Back pressure is still 1.8:1, even saw 2:1 at one point. So I'm thinking the hotside is the limiting factor at this point. Not sure what else it could be. Car feels sketchy fast on the street. Have it very slowly ramping in 20lbs VS wheel speed. IAT's are quite a bit lower. They peaked at 111. Around 86* ambient.

I'm sure it picked up a little, but I doubt it fixes my issue. Next track event is halloween weekend. I'll give it another go then.




The white "fuel pressure" parameter is the back pressure. I just never changed it.

 

I am sure that is an understatement. LOL

 

That's a shame. What part of the hot side do you think is holding you back? If I remember right 2in should be able flow 1500hp according to the flow test on that YB thread from awhile back. I'm sure you've already checked but I'd inspect quality of fuel.(especially if it's E85) Maybe even check for boost leaks. 10.2 @ WOT seems a bit on the rich side to me. But that doesn't mean much .

 

I run a completely divided hotside with 2" straight to each side of the scroll, each side having its own WG. I'm GUESSING that necking the stock manifolds down to 2" is just too much for the power I'm making. Never really planned on over 900hp, but I think I'm there.

The thread I looked at on YB said 900whp was about the limit for 2" piping. 2.25 was good for 1800+. The tune I loaded was targeting 11.0. I filled up on some "E85" right before this run. I'm guessing I got E70 instead so my tune went pretty rich. Need to verify that.

 

Oh ok I must've gotten the #'s mixed up. It's been a while since I viewed it. If the e85 tests low that would make sense. Hopefully just by switching out the fuel it'll get you a step closer. If it's indeed your hotside do you plan making another? So you could go deeper into the 8's. Or would you be content with its current achievements. Either way it's crazy how much this car has progressed over time.

 

Since I think my hotside is tapped I wanted to go back to the 30" tire but couldn't handle the way they looked. I installed my old tires on some 7.5" BS wheels and it gave me tons of clearance. Made some new lower shock mounts so I could drop the car a ton. Tucks the 30" wheel pretty well! Happy with how it turned out.