9.19 @ 145.5 For The Alky Car

[Dusty Bradford]

It's a T4 housing with a Q trim wheel. The wastegate is a HKS GTII 60mm with a 2" dedicated pipe running straight out to the side of the car.

Wow!! The Q trim is really small for what your doing. Changing the housing may gain a bit but the wheel is definately a restriction. The backpressure is probably through the roof and a bigger spring will not help. It can acutally overspeed the turbo. We see it in the classes with turbo size limits. People keep adding C02 pressure for a few extra #'s of boost but it will eventually take the turbo out.

 

[Alky V6]

OK! Today, some new records for the car.

The best run today:
1.297 60 ft.
3.704 @ 330 mark
94.397 mph @ 330 mark
5.732 @ 660
MPH not worky dirky on this run.

A few runs earlier:
1.430 60 ft.
3.886 @ 330
MPH @ 330 mark not worky dirky. Again
5.932 @ 660
120.269 mph @ 660

And my wife says the car looks like a snake going down the track.

The best run was done with a pretty warm nitrous bottle. The sun was beating down on it pretty good, even though I had it covered in an effort to keep the temp down. Pressure in the bottle was at around 1000 psi. I normally run with 900 psi. I REALLY LIKEY 1,000!!! The wheels carried to the tree. So I was told. I run the nitrous system on the rich side for cases just like this. Sometimes there will be a time where the bottle temp gets high, and when it does, I don't have to worry about the mixture being too lean. It'll just end up being PERRRFEEECT!!! :tongue:

Some interesting tuning notes. I ended up tightening the wastegate spring tension adjuster to the end of its travel. This is with the spring combo that is meant to be used with a boost target range of 127.5-166.7 kPa. I did this in search for a consistent 31 psi boost level. At this setting the boost recorded a 29-30 psi boost through the entire run. Keep in mind, I'm using manifold pressure for boost control. Not an auxiliary pressure supply. During inspection of the engine I noticed a mess around the plenum pop off which I took as the setting of the pop off being too loose and allowing boost to escape. During lower boost targets of the past, I did'nt notice any mess around the pop off. So... judging by the spring combo of the wastegate, is a low exhaust back pressure producing enough cfm from the compressor to maintain a steady 29-30 psi boost on top of the volume of air that is being lost through the plenum pop off valve?

The next test is to tighten the plenum pop off valve and back off the wastegate spring tension adjuster.

I know. I need to get that BP gauge mounted. Just thought you guys might want to take a guess on this one.

New boost target. The last run of today I had the boost controller set to 32 psi. Hopefully, this will give me a fluctuating boost of 30 to 31 with spikes to 32.

The mixture has been leaning a tiny bit with the new boost level. It's still safe. In fact, I think I like this new a/f ratio. It reads out on the O2 as 10.5 to one. It calculates out to be an actual 4.64 to one.

This engine just keeps surprising me.

 

[Alky V6]

Congrats on the new best 1/8 Don. Your IAT's seem high for your liquid IC/meth combo. Mine are consistently in the 115-120deg range at the end of a run. Circulating the water during the run would definately help your inlet temps and get that 2/10's!

Good luck!

Scott Wile

I looked over a few datalogs today, paying more attention to the IAT graph and the highest I saw was in the low 50s C. A 52 C converts to 125.6 F. I don't understand where the earlier higher value came from. I'll be keeping a better eye on the IAT to check for a consistent value.

 

[lazaris]

Thanks edv2. My website has some vids and slide shows. drwtransmission.com. I did all the fabrication.

Lazaris, you were right about the wastegate. I checked out the spring combo I have been using in the wastegate and it was a set meant to control boost between 88.3 - 127.5 kPa. My latest target has been around 200 kPa boost. I installed the next stiffer spring combo. It's meant to control boost between 127.5 - 166.7 kPa. I screwed the tension adjuster in about 1/4 travel with this spring combo. The boost now fluctuates between 29 to 30 psi boost throughout the upper rpm range. Unfortunately, the air today was worse than the air at the WCN so no new records. Just about matched what was done at WCN though, with the bad air. My best run today was .1 second off my best ever at the WCN. I lost that .1 on the 60 ft. I did set a new best mph for the car today. 118.009 in the 1/8 mile. Tomorrow, I'm going to max the boost out at 31 psi and see what happens. My boost controller and ECM aren't meant to go over 31 so this will be the ceiling for me.

I think the tires have just about reached their traction limit too. First gear's a pretty wild ride. A lot of steering.

Don,

Congrats on your new best!! That 5.73 is probably an 8.80 1/4mi. If you have that larger housing its worth a try. The wheel is probably hurting you more. Again the gauge will tell you the story. From there you can decide what to do on the turbo. Once you get into the 1.5:1 ratio in BP you really start hurting the power potential.

 

[Alky V6]

New best again, yesterday.
1.289 60 ft.
94.7 mph @ 330 mark.
122.145 mph @ 660 mark.

I ended up with the stiffest spring package for the wastegate with the adjuster about 1/4 travel in. This spring package is meant to control a boost range of 166 to just over 200 kPa. The boost stayed at a max of 29 to 31 with short spikes to 32. The boost again tapering off from 31 to 29 as rpm increased and jumping back up to 31 after each shift. This is with the electronic boost controller set at 33 psi.

Rpm drops between each shift: 7400 rpm shift point to very high 5900s after each shift.

I tried setting the boost controller to 34 and started cranking in the wastegate adjuster with no change in the boost trace. So I think this turbo is maxed out at 30 to 31 psi. Actually, this is exactly the limit that the advertised compressor map for the T76 indicates. Using my engine and drag race sims, the estimated peak HP level is around 983 bhp.

One interesting thing to note. During the final tests of cranking in the adjuster to see if there was any more boost to be had, I noticed that the car would leave the line more violently. The map rise trace would get steeper each time I cranked in the adjuster. This got me in trouble on the last run. I had the steering wheel off a bit as she came back to earth and I had to abort the pass. One other point I noticed from turning the adjuster screw in was how the tires were shocked more on the 1-2 shift. One pass the 1-2 shift blew the tires away. I would suppose that with a tuneup like that, you would want a little more slip from your T/C so you wouldn't blow the tires off from such a violent rpm drop. I've talked to some other higher HP/small tire racers that target a 1,000 rpm drop between shifts just for that reason. With a tighter T/C and the resulting larger rpm drop, the tires are shocked too much and you can break them loose. Another factor that would play into this would be the traction limit of your tires of course.

Lazaris. My sims aren't as generous as you on the estimated quarter time. I'm getting an answer of 9.001 @ 150.56 mph.

Welp, I think I'm done with the tuneup with this configuration. I now have a way to control any traction issues with the track. I can control boost rise rate by changing the tension of the wastegate spring or going to the next lighter spring package if needed. The readout for the O2 is a rock steady 10.5 to one throughout the rpm band at max throttle and boost, with the electronic injectors maxed out at 85% and the mechanical injector nozzles at a flow rate of about 80 lbs/hr.

DONE! At least until I get a larger turbo. :wink:

 

[Chevota]

I'm guessing we're both in the same "max boost" situation, so when you do find that "new" turbo lemme know! I'd hate to have to change everything to go four bolt, but with no car currently in the shop to play with I've got plenty of time to do research.:biggrin:

scott wile

 

[Alky V6]

I'm guessing we're both in the same "max boost" situation, so when you do find that "new" turbo lemme know! I'd hate to have to change everything to go four bolt, but with no car currently in the shop to play with I've got plenty of time to do research.:biggrin:

scott wile

Scott, I have to say that if I decide I want to get more oxygen in my engine, I'm very tempted to do it your way instead of fabbing up more stuff for a new turbo.

 

[Alky V6]

This is the run I had to abort because I got a little crossed up.

 

[XxDarkSidexX]

This is the run I had to abort because I got a little crossed up.

dam that is SICK DON! As I have said before you are the mother truckin man!

your contributions to this board alone without the real life contributions have been outstanding! I am glad to see you knocking on the 8 second door.

I gotta be there to video it! Let me know or PM me when you go out again to go for it!

 

[John Wilde]

This is the run I had to abort because I got a little crossed up.

Don,

Looking good, when did you put doors on the car?

 

[Alky V6]

Don,

Looking good, when did you put doors on the car?

Thanks John. You too Mark. The doors went on about a year ago. There was an accident with a barrowed car trailer that left a dent in one of the doors. Instead of dealing with fixing or replacing the steel door, I decided to put on the fiberglass doors. The change saved me 72 lbs. per door.

 

[WHITE T]

Congrats Donnie!!

It was great seeing your car at the WCN, it is amazing!

 

[norbs]

WHat is the exact converter slip at the top?

 

[Alky V6]

WHat is the exact converter slip at the top?

I've just started going over the data logs for the latest tuneup, but it looks like it's going to be 12% at the 660 mark and 8% at the 1320. I'll post the slip number again if it changes after dialing in the sims.

 

[Alky V6]

I've just started going over the data logs for the latest tuneup, but it looks like it's going to be 12% at the 660 mark and 8% at the 1320. I'll post the slip number again if it changes after dialing in the sims.

New slip number for the 660 mark is 10%. This calculation includes a tire growth figure of 5.3% by the end of the quarter. Rear tire pressures set at 9.25 psi.