Timeslip from Etown Wed Night..need more mph

[murphster]

I'm just looking over my timesheets and stuff I wrote down from Wednesday night at Englishtown in my White T Type (info in sig) and trying to decide what to do, if anything, before I go out next time to the track. After a decent day it started getting real cold in the evening and by the time I ran, it was only 43 degrees out. Even though I'm shooting for low 12's my goal was to run a 12.6-12.8 because I assumed I wasn't going to get good traction and it was my first time to the track with a new chip, injectors, EGT, and suspension setup.

I ran a total of 4 times and only had 1 good run. On the other runs I spun bad and basically ruined the times.

My best run was:
60' 1.79
1/8 8.027
mph 85.52
1/4 12.65
mph 103.7

O2 789
EGT 1549
no knock, fuel around 43.5 psi line off
21lbs boost

I was trying to figure out why the mph was so low in the 1/4. This was my second run and I never let the car cool down from driving to the track and after the first run. And I was also only running 12.5psi in the ET Streets. I was thinking I should be closer to 107mph in the 1/4 so maybe a combo of the low air pressure and heat soak contributed, not sure. I'm running 28" tires. New valve springs too. The chip is a Precision/Joe Lubrant 100 octane with 24,24,21 timing. I'm running 100% 100 octane unleaded.

All of the other runs I also finished around 103 or so. With 43psi fuel pressure the EGT was around 1589 and O2 at 777, but that run was also with a little more boost at 22lbs.

Just looking for some suggestions on what to try different next time, if anything. I'm thinking of switching over to some 26" MT drag radials because the ET Streets seem too inconsistent. Of course, the cold weather probably didn't help the traction this time around. With my high stall convertor the boost comes up so quickly with the small turbo its hard for the tires to keep traction. I may have to feather the throttle more for the first 10 feet or so. Seems like I have initial traction and then it breaks a couple feet out as the boost spikes. If the heat soak is killing me I'll consider going with a bigger stock location intercooler. I know I don't ever let it cool down enough between runs, etc.

I still want to have fun with the stock turbo before I upgrade so let me know any suggestions.

[Orlando_87GN]

A healthy running stock turbo car should see about 21-22mph difference in MPH from the 1/8th to the 1/4. Since yours is 18.8MPH something does seem wrong. You are racing it in 'D' and not shifting into 'OD' right?

Could be a multitude of things like boost decreasing towards the end of the run, valve springs tired, too much fuel delivery ect ect ect.

[murphster]

I was in "D", not "OD". Also have new valve springs. Boost seems very steady per the boost gauge. Do the O2's and EGT's look right? I guess I can lean it out some and watch the EGT and O2's. I should be able to go up to low to mid 1600's safely correct? Assuming the O's stay in the mid 700's or so and keeping an eye on knock.

I'm sure the convertor isn't helping my speeds either. I'm not locking it.

[ULYCYC]

You really can't compare EGT readings between cars. Placement 1" away from another car can be a 50deg difference. Tune for no knock and forget the O2 unless it's a WB. Lean out until knock appears then back off. Now read your EGT. This should where you should be. Also try and lock the converter it will give a a few extra mph.

[SNEARING]

That's strange Murphster!

That car was running 103 on 15/16 psi and the old stock necked I/C in 80 deg heat.

Did you ever try that mystery chip again?

[NOCOOLER]

28" Tires could be killing you - my car is a complete dog on them.

What all has been done to the car?

[SNEARING]

Originally Posted by NOCOOLER

28" Tires could be killing you - my car is a complete dog on them.

What all has been done to the car?

When I had the car it had bald 28" M/T ET streets and would trap 110 on 20 psi boost with old valve springs.

Car had a 3200 PI converter and a stock(ported) turbo, it was no dog out of the hole.

I wish I had have turned the boost up to 22 psi and tried for an 11.99 before I sold the car.

[SNEARING]

Send you a pm Murph.

[SNEARING]

Originally Posted by ULYCYC

Also try and lock the converter it will give a a few extra mph.

Car has a N/L PI 3200 in it. Unless he changed it out.

[murphster]

Like I said, first time out with a new chip and injectors. Plus I didn't let the car cool down at all after driving to the track. I could be pretty rich, right now, hard to say. I will try tuning with the EGT as suggested and pretty much ignore the O2's.

Also, the convertor turned out to be an old Art Carr that looked just like a PI. I had it freshened when the trans was rebuilt late last year.

SNEARING, the "mystery chip" had high timing and I was getting knock with 100 octane and high boost. The car was fast before, but it was very lean on the top end and I didn't want to push it so I upgraded the injectors.

I'll be getting a Turbotweak chip soon anyway with a little less timing in 3rd so I can run more boost. With their new chips you can adjust the fuel with the chip instead of using fuel pressure. Can also adjust the timing too.

The car flies out of the hole, just can't hook. Don't know if it was the low temps or the setup. I ran a 12.4 last year on 100 octane with a little better launch and a little more boost.

The car still has more in it as its running through stock elbow and Poston's downpipe along with Flowmasters. I'm hoping to gain .1-.2 when I upgrade to a THDP and ATR exhaust one of these days.

SNEARING, replied to the pm. Here's what the engine looks like now by the way.

[SNEARING]

Wow that looks WAY better now. Looked like azz when I sold it to you.

[Ray Kammer]

I think if you'd lock the converter and run a 26 or 27 inch tire, you'd MPH around 105-107. 28" tires are way too tall for this combo IMO.

[ACLR8TR]

I bet the intercooler was heat soaked, and that is what hurt your MPH. I did the same thing last Friday made 3 runs as soon as I got to the track, they were all 110mph, let the car cool for an hour (didnt change anything) and then MPH jumped to 114.6. So if you let yours cool down I bet you could get at least 2-3 more mph.

[murphster]

Thanks for the advice everyone. I'm still thinking that the heat soak was one of the main reasons the mph was low.

I'm considering going to 26" tires, but I've read that the 28" tires can help the launch when the track is poor (such as Etown on wed nights). I've also read that the 28" tires are good for a combo like mine...loose convertor with small turbo. Another reason for the 28" tires is that if I upgrade the turbo later this year (PT61) then the 28" tires are the way to go for sure.

Although I can lock this convertor to squeeze a little more mph, I'd rather keep it unlocked and have a little less wear and tear.

I may upgrade the intercooler, downpipe and exhaust before I upgrade the turbo just to see how much difference it makes. A couple more tenths and a good launch I'll be real close to high 11's. I'm looking at getting a THDP, ATR 3", and the PTE stock location intercooler. Hard to say if they will make much difference with the stock turbo, but can't hurt. For the bigger turbo they will definitely help.

I got my turbotweak chip in yesterday and put it in right away. I forgot how nice an open loop idle can be along with smoothing out the high stall convertor. So much better now. From just a few speed bursts the numbers look like this chip is a little leaner compared to the previous chip. I can also adjust the WOT fuel and timing with this chip too so I should be in good shape. Not even a hint of knock(25/20 timing) and the EGT's still look good at 22lbs boost. I'm hoping with the ported stock turbo I can squeeze 23-24lbs boost. All on 100 octane.

[murphster]

Went out to Etown tonight to try out the Turbotweak chip. I changed nothing from last week and the conditions were almost identical with temps in the low 40's. I gained 3mph on my fastest run!

I still couldn't hook worth a damn, but my main goal was to increase my mph, and that I did. All I basically did was add a little WOT fuel each run through the adjustable features in the Turbotweak chip and watch the EGT's and mph to see what would happen. I couldn't have asked for a better night, there weren't many people there and it was basically like a track rental. I got there late and hot-lapped the car for 6 runs in a row with barely a rest between runs, only 1 minute rest on the last two runs. I felt the intercooler between runs and it didn't feel hot at all. So maybe heat soak had nothing to do with the previous night at the track.

I was able to add fuel each run and the mph went up while the EGT's went down accordingly. I added about 2% WOT fuel per run and then toward the end the mph started going back down while the EGT's kept lowering. So it looks like I may have found the sweet spot for my car at around 1670 EGT's or so. O2's were low to mid 700's, but they were a lot more erratic each run than the EGT's and are basically worthless.

On my best run I ended up with 106.5 mph! Thats a gain of almost 3mph from last week's best of 103.7 with the only change being the chip and playing with WOT fuel settings. I didn't have any knock on any runs and was even running less timing in 3rd than last week (20 vs 21). I ran out of time when the track closed or I was going to add one 1 more lb of boost in third. I probably could have gotten close to 108mph I figure. I would have been in the 12.2-12.3 range tonight with a low 1.7 60'. May still try 26" tires down the road to see what happens.

Thanks for all the help and advice (And a big thanks to Eric at Turbotweak ). Looks like I'm starting to get it dialed in. EGT and chip adjustability is the way to go! Just need to work on the launch now and wait for a little warmer weather to get some traction.