Car is slower than ever, need help

[mustangtcs]

Background on car. 05 GT Kenne Bell 2.6 9lbs. Lund tuned 460rwhp 450rwtorque. 4.10 bmr lowers and relocation brackets. Automatic w stock stall. Dynotech driveshaft. M&H Racemasters.

May 30, 2014 I took the car to Atco for the first time ever. Ran 11.96 at 114 with a 1.7 60ft and no spin. IAT's were 150. Tune started pulling timing at 130.

After this I installed the Afco dual fan heat exchanger and Lund adjusted the IAT's to pull at 140. Also I had a bog if I stabbed the gas from idle and he fixed that also.

August 24, 2014 Back to Atco. I ran the car and the IAT's were 120 so not pulling timing and the 60ft was again 1.7. 12.06 at 111 mph. Disappointed I ran two more times and no kidding I got 12.06 at 111 mph every time.

My problem is I thought the car would be faster now that I have full power and not pulling timing. I feel as if the mph is not reflecting the hp I am making. In May the car was pulling timing before the run even started. Now the car never pulls timing and I have logged and checked and it stays at 19 with no fluctuation at full throttle to redline. I'm not sure what to do?

 

[stkjock]

did you check the DA difference?

May 30th to Aug 24th could be a big difference in the air.


as a general ET comment, a aftermarket stall would likely make a big difference in you 60's and ETs

took a quick look - seems to have been a 10* temp diff and a 20% humidity difference - that's some ET there

 

[mustangtcs]

Lund Jr said the same thing you said. But I thought with more power and no bog at all the car would be faster despite the DA. I thought 460 rwhp would have a higher trap than 111 mph. But I am new to drag strip racing so maybe this is the answer. I will do a stall converter and input shaft. I was thinking PI or Cirlcle D. He also said maybe the converter isn't locking. I am going to buy a laptop today and try to figure out how to log converter lockup and see if I can on the street but probably won't be able to do fourth to redline. Anyone know which PID 's to select for that and to check shift points?

did you check the DA difference?

May 30th to Aug 24th could be a big difference in the air.


as a general ET comment, a aftermarket stall would likely make a big difference in you 60's and ETs

took a quick look - seems to have been a 10* temp diff and a 20% humidity difference - that's some ET there

 

[stkjock]

the power will not be there with the difference in the air.

however yes 111 seems a bit low for 460 WHP, my 06GT at 460 would trap more like 117-118 in good air. However keep in mind a dyno sheet is just a number, they vary from machine to machine and the air can effect it to (unless that number is corrected)

as far as PIDs - ask Lund Racing what they would want to see

 

[Riptide]

My kb 2.6 car trapped 112 in 5000' air. Fyi


Sent from my iPhone using Tapatwat

 

[psfracer]

Mine used to trap 119-120 with 474 rwhp, with good DA (less then 1,000), a long time ago in a galaxy far, far away.

What are the incrementals on the timeslip? How heavy is the car? Assuming normal weight, mph should be 117-119 or so.

How do you know timing was not being pulled? Datalog (I guess so based on what you posted). Are your knock sensors working? What gas are you using? Any signs of belt slip (black dust all over your pulleys)?

EDIT: so I was thinking--your stock converter could be slipping on the big end. When my stock converter went south, the rpm on the big end fluctuated weird, and my mph dropped like crazy. ALSO, something to do easily is to change the plugs. That was the first thing we used to do when mph dropped off with no apparent reason.

 

[mustangtcs]

Time slips from both months. Car 2024 in may

 

[psfracer]

the small difference in 60' and mph at the 1/8th could be explained by different DA or track conditions:

60' = 1.71 - 1.73 - 1.74
1/8th ET = 7.63 - 7.70 - 7.70
1/8th mph = 90.70 - 89.67 - 89.83

So less than 1 mph difference from the last time to this time on the 1/8th. But look at the mph at the 1/4

1/4 mph = 114.65 - 111.34 - 111.54

So you have a .87 mph difference at the 1/8th, BUT you have a 3.11 mph difference at the 1/4. Something is happening on the big end. Assuming you haven't changed anything from the two outings (you eliminated the tune pulling timing), you are using the same gas, same gearing, same tire, etc --and the DA is pretty much the same then:

1) change plugs
2) look at your rpm data log on the big end, does the rpm fluctuate? If the rpm is fluctuating/jumping vs a steady increase in rpm, then your converter is locking/unlocking or slipping. If so your stock converter is starting to go away.

 

[mustangtcs]

I didn't datalog at the track. I did it yesterday on the street. Here is a video from the track and it sounds like the rpms fluctuate but it's hard to really tell on video.

https://www.youtube.com/watch?v=SsxWAtXEww4&list=UUQ9WlaDA7KjzULGFlrdwNwQ&index=5

 

[psfracer]

Yep I can hear it. Definitely something happening on the big end.

 

[swflastang05]

My old combo was 440whp and it ran 11.62 @ 115 last time out, super humid night & shit DA. Although I later found 3 of my plugs had broken cores, that very well could be it, as stated above, and it's an easy enough thing to do & eliminate that possibility. (Procharger and 5r55s tranny w/3000 stall convertor, 4.10's)

 

[mustangtcs]

I just switched from Autolite HT0 to Brisk 1 step colder plugs 1,500 miles ago. No change at all in drivability or anything on the street, idle or anything. Never ran the HT0's at the track though. Would my Brisk plugs go bad that fast?

 

[dysan]

I've read mixed results on the Brisk plugs and stayed away from them when I had the old style heads on my car. Those people who had Brisk plugs foul I believe they did foul quickly on them.

 

[mustangtcs]

Lund and Evolution said take out The HT0's and install Brisk. Someone just told me to try the ford racing M-12405-3V0 plugs. I have read they are the same as Autolite's. Does anyone know if that is a fact? Or just the same style and heat range? Should I ditch the HT0's, pull the Brisk, and install the Ford racing? This is over $300 in plugs thru guess work on my end so any help is worth it.

 

[05moneypit]

Brisk's were garbage in my engine, would miss at high load in 3rd gear (4R70 trans) no matter what gap I had them at. HT0's have always worked fine for me all the way up to 25 lb of boost.

 

[dysan]

The ford racing plugs are the autolite plugs. They are the ones you should be using in my opinion(autolite HT0's). At 9psi boost I would be gapping them around 032.

I suspect you are going off the date on Atco's timeslip which was off by a day for a while this year since the 30th was a Wednesday so I'm guessing you were there on a Tuesday night which would have been the 29th. The weather that day/evening looking at the Drag Times DA chart was phenominal... the barometer was 30.17 which is crazy good and the temps from 3pm on were 60F down to 55F so you had killer air then.

On Aug 24th (this past Sunday) the barometer was still good at 30.10 - 30.14, the temps were 72F - 80F which makes a huge difference on a blower car on gasoline. Another thing to consider is that the track prep on a test and tune day like this past Sunday isn't going to be nearly as good as a Tuesday night gamblers night or a Saturday points race day so that could have played into it a bit.

Atco is my local track so I'm there at least two times a week racing so I am quite familiar with how the track changes on certain days.

How were you checking your IAT's? Datalogging or interceptor gauge?

I am inclined to say a lot of the change has to do with the air difference in the two days. I can a swing on my car of a few hundreths of a second in a single day as the air changes...you're looking at a difference of a tenth which I can see as feasable given how different the air was between your runs.

 

[psfracer]

No doubt DA plays a large role, BUT.....

how do you explain what his car is doing on the big end? That is not DA, something is up. 1st, DA wouldn't only affect the 2nd half of the run, it would affect the whole run. 2nd, did you hear what his car is doing on the big end in the video? That does not sound right at all. I still say plugs or converter.

OP--you said you switched to Brisk from the HT0s. Do you still have the HT0s that you can put back in to see if there is any difference? What did you have the HT0s gapped to, and what are the Brisk plugs gapped to?

 

[dysan]

I just listened to his video and one of my old videos and it sounds to me like the converter is locking/unlocking.

Here is a video of mine from a while back...my friend was trying it out and he locked the converter somewhere between the 1000' and the stripe...you can hear the rpms change all of a sudden.

 

[TungstenGT06]

I agree with what Dysan told you. I was there that day watching and it was really warm in the afternoon. That will definitely slow you down from your previous runs that you had in better air.

 

[psfracer]

I just listened to his video and one of my old videos and it sounds to me like the converter is locking/unlocking.

Yep, thats what I am saying. (post #6, #8)