Loss of MPH in the Quartermile

[AKTURBOTA]

In July I replaced my stock MAF with a Translator Plus and an LTI MAF. I didn’t have the extra leads, so I didn’t connect the spark timing functionality of the T+. I went to the drag strip with the T + adjustments base at 3 and WOT at 0, expecting to take care of my low MAF readings (238-242 max), but was disappointed that the LTI MAF didn’t make a difference. Performancewise I turned a best of 11.94@113.14 in the ¼ mile and 7.611@90.36 in the 1/8th mile. My Turbo TA typically has a mph between 113 to 115. Given it was a hot day, I felt that the car was performing OK. What did turn up was that the IAC counts were way off, so I adjusted the minimum air rate to factory specs.

In the meantime I installed Global West subframe connectors, Spohn adjustable torque arm, lower control arms and an adjustable panhard bar. Additionally, I purchased a “plug and play” adapter so that I could connect the spark timing functionality of the T+.

I went to the drag strip yesterday and ran the car for the first time with the new suspension components and also set the T+ to 3 for MAF base, 0 for MAF WOT, 0 for spark base and 0 for spark WOT. The PROM chip I have is a Caspers Ultimate 7 position set on #5 chip. The best time I could record was a 12.20@109.2 in the ¼ mile and 7.87@87.05 in the 1/8 mile.

While it was a 60 degrees and humid the track wasn’t prepped very well, so traction was somewhat compromised. I am perplexed on what I could have changed to cause such a lackluster performance. It appears that I lost 40 hp somewhere, part of it maybe due to atmospheric conditions, but it can’t be all of the reason.

I hope that I have the correct setting for the T+ mode switches. I have as follows

Switch 1 ON
Switch 2 ON
Switch 3 OFF
Switch 4 OFF

The #3 switch I am not sure of. The instructions I have from Ramchargers has quite a few typos, which makes me somewhat skeptical that I may not have all of the right mode switches set correctly. Should switch #3 be set on or off for a TTA not running an extender chip?

I have complete Turbo Link runs recorded and available for viewing if needed. It seems that something isn’t right with my setup for T+. One thing I am going to do is replace my heated O2 sensor. It is 2 years old and has been subjected to leaded racing fuel for the past two seasons. If anyone can help me, it would be most appreciated.

Mark
Eagle River, Ak.

[Slow91z]

Wow, ain't this funny...I just posted on a thread that was just like this...O wow it was this!! Like I said in the your other thread tuning is imperative, suspension and engine.

[Razor]

TTA lessons..

One mod at a time and only after track sessions can the next one be performed. The best way to say this..if you have a stock MAF sensor, put it back on and see if the performance increases..

I had a similar experience with mine..lost 4-5 MPH from one week to another no changes..it went down to 112 MPH from 117 MPH..after the third 112-113 pass.. I pulled off my KN and on the next run..bammm 117. So sometimes stuff happens to things you never think about..

Also had a situation whereas a stagerite trans brake I installed cuased the car to lose 3 MPH as well..took it out..bamm..up went the MPH. Weird..but hey thats why 1 mod at a time.

yes I cleaned my KN and all is well..

BTW, Steve would you like some cheese to go with that wine

I find that by looking at recorded runs I can pull a lot of information to ascertain whats going on. Unfortunately i'm not versed with turbo link.

HTH

No the wine doesnt harm performance..Fastest TTA's all have a llittle wine..

[AKTURBOTA]

Well I though I was more or less doing one mod a time. In July I replaced the MAF with the LTI sensor and T+ and the cars performance was about the same. The only difference in August is that I connected the spark lead from T+ to the plug and play adapter at the ignition coil. All of the setting were set to basically neutral adjustments. Additionally, the suspension mods were new as well, but I don't believe they would impact the MPH of the car.

I am going to replace the O2 sensor, but if someone could tell me if I should have the 3rd mode switch on or off in the T+, I could eliminate that as a potential problem.

If the above doesn't do the trick I am going to go back to the stock MAF to see if that does the trick.

Any comments on why my MAF readings don't peg out at 255. I am only seeing 238-242 max?

Mark
Eagle River, Ak

[brn agn]

From what I have been told (and what I have read), switch #3 should be ON if you are running a chip other than an extender and OFF if you are running an extender. BTW, I recently swapped an LT1 MAF and Translator into my TTA. I was also getting low air flow numbers...I changed the setting to a 3.5" MAF and the numbers started maxing out...I have no hard evidence to prove that performance increased, I only have what the scan tool showed. Hope this helps.

[AKTURBOTA]

Thanks for the info, I am going to turn the 3rd switch to the on position. Regarding the setting for 3.5", my understanding is that it leans the mixture at the base setting. I wonder if my understanding is true.

Mark
Eagle River, AK

[brn agn]

My BLM's at idle actually dropped considerably when I switced to the 3.5" setting...which suggests that the computer is pulling more fuel out. I have not had a lot of seat time with the MAFT in this position...so take my advice with a grain of salt.

[trading t/a]

I know you gave a lot of info, but what were your CC's and what were the o2mv's? It could be a few things. The new maf should still peg in the 248-255 gm/sec area. After it reaches it's max airflow the ecm will not adjust the fuel any further. The extender chip fools the ecm into thinking it sees half the value it actually does. 255=510gm/sec. It enables a better fine tune using the trans+ to adjust fueling.

As I remember even if you have the trans+ it still wouldn't do any good at w.o.t. cause the computer is locked out when it hits the airflow limit or maybe I didn't hear it right. Another question is do you see maf dropout at all. I experienced a lot of it using a thrasher chip for some time. I would look into a rich condition. When I swapped mine I could never get the o2's to go below 880's or so. That's even pulling out the max fuel and adding like 6 degrees. Is the screen still in the maf? I gutted mine and saw slightly leaner conditions. You may want to investigate pulling the screen and switching it to the 3.5 LS1 sensor and see if it leans out(but not too far ) that may give you a little tweaking ability to run the mph you're missing. It does take a while with it. I first started around the 108-109 area (partly due to the enormous turbo) after tweaking the fuel and timing I was able to lean it out enough to pull 114 mph's with around 16-18 psi.

HTH!

[AKTURBOTA]

I was going to attach the spreadsheet that contains the T-Link run, but cannot. It probably is a moot point since I had the 3rd mode switch turned off for the T+, whereas it should have been in the "on" position. The car was definitely not "pulling on the top end" like it used to with the stock MAF, so I am hopeful that turning the 3rd mode switch to "on" will make the difference. Iam going to the track on Labor Day to see if it makes a difference. Additionally, I have replaced my O2 sensor.

Mark
Eagle River, AK

PS:

Interestingly enough I was at the track on 7/4/03 and it was the first time that I had the T+ installed with the incorrect setting for the #3 mode switch and my mph's were very close to what I was running with the stock MAF. So I wonder why my mph decreased from 113-114 to 109 on 8/24/03 with no other changes except for my suspension mods? It is a perplexing mystery.

[AKTURBOTA]

I went to the track on Monday, 9-1-03 and concluded that my problem with the loss of 4 mph in the quartermile was due to the having the 3rd mode switch in the T+ turn off when it should have been "on." The instruction that were included with the T+ weren't very clear on the base setup for a V-6. I found the performance I had before, but I still can't max out my MAF #'s. I have checked for vaccum leaks and found none. I had the stock valve springs replaced upgraded to the ones that Kirbans sells. I have reset my minimum air rate and my WOT TPS voltage is 4.58 to 4.6. I have run out of ideas. Something isn't right, but I do not know what. Any ideas?

Mark
Eagle River, Ak

[Razor]

Bad MAF?

[AKTURBOTA]

That what I thought when I had the stock MAF. I replaced it with the LTI MAF using the T+ and found that there was no change. I still was not maxing at 255 at WOT.

Mark

[Razor]

there are only two parts, the MAF and the ECM.

Find someone you can swap MAF's with and see if your meter goes to 255 on their car.

If it does..then it points the finger at the ecm.

Pull the KN off and see what it does?

[AKTURBOTA]

By setting the mode switches correctly in the T+, I've got the car to run back to where I started from before the T+. Now will be working on dialing it in for the best mph at the track. I was considering upgrading to the extender chip, but I do want find out what is cause the "low" MAF sensor readings first, before moving onward.

Checking the MAF sensor on another GN/TTA to see if it will work the same or improve does seem like a good way to narrow down the problem. My gut feeling is that it is neither the MAF sensor or the ECM, but a vaccum leak somewhere...but where I don't know.

Even though my MAF #'s are in the 238 to 244 max, I have turned a high best mph of 117.2 and an ET of 11.79.

One possible area I need to look into is boost control. Presently I am using an ATR bleed valve on my TA49 to adjust boost PSI. I have noticed that boost doesn't stay on an even plane, but varies by 2 PSI in a quartermile run. So it appears that boost control may be playing a role here. I understand that boost can spike between gears, but for me it generally drops a couple of psi when the car upshifts.

I also cleaned my K&N airfilter and changed my O2 sensor with no perceptable improvements.





Mark
Eagle River, Ak

[TurboDave]

Originally posted by AKTURBOTA
By setting the mode switches correctly in the T+, I've got the car to run back to where I started from before the T+. Now will be working on dialing it in for the best mph at the track. I was considering upgrading to the extender chip, but I do want find out what is cause the "low" MAF sensor readings first, before moving onward.

Checking the MAF sensor on another GN/TTA to see if it will work the same or improve does seem like a good way to narrow down the problem. My gut feeling is that it is neither the MAF sensor or the ECM, but a vaccum leak somewhere...but where I don't know.

Even though my MAF #'s are in the 238 to 244 max, I have turned a high best mph of 117.2 and an ET of 11.79.

One possible area I need to look into is boost control. Presently I am using an ATR bleed valve on my TA49 to adjust boost PSI. I have noticed that boost doesn't stay on an even plane, but varies by 2 PSI in a quartermile run. So it appears that boost control may be playing a role here. I understand that boost can spike between gears, but for me it generally drops a couple of psi when the car upshifts.

I also cleaned my K&N airfilter and changed my O2 sensor with no perceptable improvements.





Mark
Eagle River, Ak

Sounds like the car is running well enough! What kind of boost are you running. What mods does the engine have? Turbo? Injectors?
INFO, INFO, INFO! SETUP?!

[AKTURBOTA]

Dave,

Thanks for responding. The following is my TTA's present combination:

7 position Caspers "Ultra Chip"
TA49 Turbo
36# injectors,
Action Fab 3” downpipe
freeflowing exhaust with testpipe
62mm throttle body
ported plenum
adj fuel pressure regulator
ATR bleed valve to control boost
PTS 9/11 Torque Converter (Stalls at 3400)
LT1 MAF Sensor
Translator Plus
K&N 8" Air Filter on 3" Stainless Steel MAF pipe
110# valve springs
On the street I run 92 Chevron unleaded premium
At the strip I run Sunoco NOS Supreme Racing Fuel (117 octane)

At the strip my fuel pressure is set at 45#'s with the vaccum off and I run 21-23 #'s of boost. I have run with the #5 chip which gives me 22 degrees of advance at WOT and knock retard usually never exceeds 2-3 degrees.

I have Turbolink runs recorded and are available for viewing if more information is desired. I feel that there is more potential with the present set of mods.

Thanks,
Mark

[TurboDave]

Good Grief!!! With that setup you're complaining about running 11.7's at 117????

You're running what I run, and I'm happier than a "pig in a poke".

I do find one thing a littel strange though. The fact that you run 117 octane gas, 22# of boost and 22 degrees of timing and you're still seeing knock

Might have something to do with the fuel though. Not something I've been particularly impressed with. One other point on the ultra high octane fuels, is that they are generally designed for use in Pro Stock type motors that turn HUGE rpm. It's designed to burn very fast for the 8000-9000+ rpm they run.


I have had MUCH better luck running Unocal 114 (better even than VP-C16). I run 25-27# of boost, and 28° of timing at the track, and no knock retard.



As for the MAF not topping out. That could be chip related. Have you another chip brand to try?
Also, what are your idle BLM values while sitting at a traffic light after the car's warmed up good??

It wouldn't do me much good to look at a Turbolink file. I don't have a working TL, and besides, in an 11 second run, you're only going to see about 7 or 8 frames of useable data.

[AKTURBOTA]

Dave,

Typically I run in the 11.90-12.00 at 113-114mph in the quarter. The 11.79 ET and the 117 MPH were all time best numbers and were accomplished in different years, 2003 and 2001 respectively.

The BLM's at an idle have been around 149. This BLM is with the coolant at 169 degrees and in the staging lanes. I will need to hookup Turbolink to get the nontrack BLM's. For the street I run 40# of fuel pressure and at the strip I run 45#'s of fuel pressure. At WOT and my best run on 9-1-03 they are 130.

Ive used different chips by two different companies and it hasn't made a difference in the low MAF numbers.

The spark retard with the 117 Sunoco fuel has been perplexing, but I have also used Trick 114 and VP C-16 racing fuels all with some spark knock. I'm not sure what to think.

I think I have a good running car, but feel that it is not at its full potential given the mods.

I have a converted a T-Link run into an Excel spreadsheet and can email it, if it would be of any assistance.

Thanks for putting up with my "trail of facts" Hopefully I am providing you with revealing facts


Mark