Ugh.....

[incubus2432]

60 ------1.74
330 -----4.99
1/8 -----7.71 (89.78 MPH)
1000 ---10.09
1/4 ----12.10 (110.95 MPH)

My previous best was 12.45@115.26 with a 60 ft. of 2.06. My times fluctuated but my MPH was always around 115. Since that time I have replaced the restalled D5 with a PTC 3200 l/u converter and mounted drag radials (and some other crap I'm sure).

It feels great and pulls strong the whole way down the track. I only had three runs last night and had a Powerlogger malfunction for the last/best run (figures). For the other two runs my launch was off the footbrake at 11-12 PSI, wideband showed 10.5-10.8 AFR with zero knock. Converter locked shifting at 5600 RPMs. Previously my boost was always a steady at 25lbs. (+/-0.5) now it starts the run at 25-ish and creeps to 29-ish at the end. No big deal since I have no knock but it makes me hesitant to pull fuel or add timing.

I'm happy with the 60 ft. and the ET is an improvement but I'm a tad disappointed by the loss of MPH. I was hoping with a 60 in the 1.7 range I'd get comfortably into the 11's. I did find that the Nittos need to be roasted to get good grip.....my other 60's were with an "average" burnout resulting in a 2.0-ish 60 with wheel spin but when I torched 'em good I got the 1.74 with no spin at all and I'm sure there's more in 'em.

I'm not sure if the converter is the main reason for MPH loss. Dusty did mention that the 2800 l/u might have better MPH than the 3200 but that the 3200 would launch better and get inefficient for a high 10 second car.......which mine clearly is not. Not sure where to go from here and the season is about over.

 

[QwuickTurbo6]

well the run looks like a high 11 second run up to the 1/8th mile....the problem is you didn't pick up enough mph on the big end. Are you positive the converter is locking because an unlocked converter slipping might be your mph issue. I actually had the same problem with my PTC 10" 2800 l/u and a TT chip. I just put a manual switch in and locked it in 3rd for another 3 mph

 

[incubus2432]

Yep, I have a manual switch and I locked it.

I would have liked another run with a good 60 ft. to see if it was consistent at that MPH. Since I don't have a log for that run I don't know if there was another issue at play.

 

[QwuickTurbo6]

Whats the tire height with those bigger wheels and what do you got timing set at?

 

[incubus2432]

Timing is at 23/21 and tires are about the same as stock.....26" IIRC.

 

[DIAZ 87]

I was wondering if your still using the stock axle's launching the car @ 11-12 lbs

 

[Dusty Bradford]

What was the trap rpm when you crossed at 110 mph?

The mph will be down from a D5 just due to the converer being a good 1000 rpm looser than what you had. I'd like to know if the rpm was high if you had locked it. Being a single disc converter, they won't tolerate WOT locking for long.

 

[QwuickTurbo6]

I find it incredibly hard to believe that a 61mm pushing 29 psi only netted 110 for a trap speed.

 

[incubus2432]

What was the trap rpm when you crossed at 110 mph?

Again, I can't say for sure because I didn't log that actual run but on the previous pass it hit 110 at 5550 RPMs.

With the restalled D5 at 110 MPH it would be at 5150 RPM.

I find it incredibly hard to believe that a 61mm pushing 29 psi only netted 110 for a trap speed.

Me too. When I was consistently running at 115 MPH the boost was at 25psi flat. I take a step forward with the better 60 ft. and lose on the top end.

I need to hook up with a track rental so I can get some back to back runs for firm data and the ability to tweak. Getting three runs with an hour between each and diving fall temperatures doesn't make for a good tuning session.

 

[Dusty Bradford]

What about the cam and valve springs. It seems the car did not respond to the increase in boost which can point towards valve springs. When you get some data, pay close attention to the rpm. Look to see if it reaches a certain point and sort of flat lines.

We know the 10" 3200 will give up some mph to a D5 because those converters are so tight. But the car should also respond to the increase in boost. If they don't, the 1st culprit is usually lack of spring pressure.

 

[turbo nasty]

I bet its laying on the convertor if hes shifting at 5600. But as Dusty said check teh Rpm's and see if it is indeed pulling all the way up

 

[incubus2432]

I was wondering if your still using the stock axle's launching the car @ 11-12 lbs

Yes, still the stock axles. I wasn't too concerned about 'em since traction has been an issue. They are on the upgrade list though. The 11-12 psi launch was on runs where I had wheel spin.....I think the 1.7 60 ft. run was lower but I have no way to confirm how much. Maybe it was only 5-6 psi......but who knows?:redface:

What about the cam and valve springs. It seems the car did not respond to the increase in boost which can point towards valve springs. When you get some data, pay close attention to the rpm. Look to see if it reaches a certain point and sort of flat lines.

We know the 10" 3200 will give up some mph to a D5 because those converters are so tight. But the car should also respond to the increase in boost. If they don't, the 1st culprit is usually lack of spring pressure.

The springs were replaced in '07 with Comp Cams 979's.

Here are a couple of screen captures.....

With the PTC 3200 l/u.....

With the D5.....

 

[street6]

just out of curiosity, why did you go from a 12" D5 to a 10" 3200 with such a small turbo? I did the same thing a year ago and here were the results from a stock motor/ heads with a TE60 @ 22#'s boost

12" orange stripe l/u

60---2.022
330--5.371
1/8--8.162
mph-88.42
1000-10.55
1/4--12.58
mph-111.6

10" 3200 l/u

60---1.62
330--4.90
1/8--7.73
mph-86.6
1000-10.20
1/4--12.23
mph-106.26

................a loss of 5 mph (needless to say I was mad, and kept thinking I was getting out of it before crossing the 1/4 mile line w/ the 10" b/c of the low mph but I was not). I now have a different build (new motor/trans) but same turbo and I'm using a much tighter converter (9.5" n/lu which gives me 2600-2700 rpm @ 0 boost....and I'm able to build about 9 to 10 #'s boost at the line). just finished install about a week ago so no track times yet....still tuning.

 

[incubus2432]

just out of curiosity, why did you go from a 12" D5 to a 10" 3200 with such a small turbo?

Because I'm a tool? :biggrin:

Well, with my D5 I just couldn't get it to launch hard......even leaving the line with some boost built it would just fall on it's face until it rolled out a bit. After some deliberation and knowing that there are tradeoffs I chose the 3200 over the 2800 stall because, per Dusty, it would launch easier. My car is 99% street driven so daily performance is more important to me than dragstrip numbers. I also opted for the 3200 because I can't leave anything alone and figured it would "future proof" me to an extent......heads, cam and a new turbo can't be far off judging by how much I seem to love debt.

I am quite pleased with the car on the street and am not really upset with the dragstrip performance.......I was hoping for mid 11's (taking my old MPH into account) but it was an improvement time wise. Also, while the tune is "good" I am a bit on the conservative side so I'm sure I am leaving enough power on the table to get me to my goal. Maybe a 2800 would have been a better compromise for my current combo but who knows.....maybe it would have still given me trouble in the 60 ft. department?!?! Whatever....it is what it is.

 

[street6]

Same reason why I did it a year ago w/ my car...lol

Now I try and stick with the tightest converter I can that will give me 5-8#'s of boost at the line with the turbo I'm using. For my mostly driven street car I think it's all the converter I will need.

On my new build (in sig) I am using a Pats Performance 9.5" n/lu 3000 stall converter. Even though it has an advertised stall of 3000 it will only reach about 2600 rpms @ 0 boost (with my TE60). At 3000 rpms I can hold about 8-9#'s at the line. Pats Performance does not rate their converters at 0 boost so an advertised 3000 stall converter through Pats is significantly tighter than a "3000 stall @ 0 boost" rated converter.

Praying I will not have to change converters again.

 

[Dusty Bradford]

If your WOT WB02 reading is correct, the 10.1 AFR is a problem, it's drowning in fuel and putting an increased load on the entire ignition system. You could pick up some mph from getting is closer to 11.1-11.3 at that boost level.

The comp 979's may be enough pressure. Without knowing where they actually checked at before installation and what your installed height is, it's hard to say if they can be a problem or not. I would have to say the car would respond to more spring pressure though. These cars need 100# on the seat at this boost and rpm level. A spring at 70# just won't cut it. I think it's worth looking into.