1/4 Mile Guys, HELP. Analyze My Timeslips

Swarzkopf · May 7, 2006

This will be a long post. If you help me, I'll really, really appreciate it. :SNSign:

Went to the track yesterday.

Last year, I was running low 13s. My basic setup was:

-Stock 5.0 from oil pan to throttle body
-AODE with B&M shift kit, stock torque converter
-Zex dry 125 shot
-4.10s
-190lph fuel pump
-Aeromotive fuel pressure regulator
-BBK-off road H-pipe, flowmasters
-BFG drag radials
-CAI

My best ET was obtained from launching off idle on the nitrous. Here it is, complete slip:

60'-- 1.943
330-- 5.685
1/8-- 8.710
MPH-- 82.32
1000- 11.268
1/4-- 13.343
MPH- 104.48

So this year, I made some changes. Here is the setup from yesterday, with changes in bold:

-94/95 Cobra intake manifold
-Proffesional Products 70mm throttle body
-Professionally rebuilt AODE w/"race grade" internals
-Edge Racing "Street Edge" 3000 RPM stall lockup torque converter
-Powertrax "No Slip" locker differential
-Stock rubber intake tube back on
-Zex dry 125 shot
-4.10s
-190lph fuel pump
-Aeromotive fuel pressure regulator
-BBK-off road H-pipe, flowmasters
-BFG drag radials

I ran four times. Here's the complete slips and their background:

Run #1: I wanted to be cautious as this was the first time I'd be spraying 125 with the new found airflow from the Cobra manifold and throttle body, so I bumped fuel pressure to 46 PSI/vacuum on. Also, I didn't know until after I left the track, but my plugs were gapped to .040, which is the gap I run with a 100 shot. I forgot to gap them for the 125. I launched off idle into the nitrous and spun both BFGs a bit:

60'-- 1.989
330-- 5.705
1/8-- 8.827
MPH- 78.33
1000- 11.535
1/4-- 13.819
MPH- 98.22

Well, MPH was WAY down along with ET, so I figured I was rich and dropped fuel pressure to 43 PSI/vacuum on.

Run #2: With fuel pressure now at 43/vacuum on, I launched off idle into the nitrous again. I turned the juice off during the 1-2 shift here, but didn't really need to:

60'-- 1.927
330-- 5.787
1/8-- 8.972
MPH- 77.20
1000- 11.711
1/4-- 14.006
MPH- 100.42

Run #3: With an increase of 2 MPH, I dropped the fuel pressure to 41/vacuum on. I launched again from idle into the nitrous:

60'-- 1.888
330-- 5.678
1/8-- 8.828
MPH- 78.05
1000- 11.537
1/4-- 13.808
MPH- 101.51

Run #4: I dropped the fuel pressure to 38 PSI/vacuum on. I tried launching the same way as the previous three runs...and the tires BURNED the **** off! I blew the tires off and had to completely let off the gas and get back into it...results were horrible and will be abreviated:

60'-- 2.582
1/4- 15.002
MPH- 95.49

Summary:
After adding a Cobra manifold, 70mm throttle body, rebuilt AODE w/"race grade" internals, "Street Edge" 3000 RPM torque converter, Powertrax "No Slip" locker differential, and the stock rubber intake tube I lost .5 off of my ET and 3 MPH (when I expected to GAIN .5 and 3 MPH!).

HELP!

94gts · May 7, 2006

based on the new things that you did, something is not right mechanically.

personally, i dont think the fuel pressure and plug gap slowed you down THAT much. im sure it did slow you some, but not enough to see the negative results that you got.

Swarzkopf · May 7, 2006

I would tend to agree, but I really don't know where to start...

Manifold generates enough vacuum..no noticeable leaks. Doesn't leak oil or coolant.

Throtte body opens fine.

I think they're installed correctly.

I think the car is down on power- I don't think it's a tranny problem. Last fall with this transmission on the street it would CRUSH the rev limiter between 1-2 if I tried spraying through the shift; yesterday, it was fine. Tells me the car is down on power/torque...I just have zero idea why.

Grn92LX · May 7, 2006

Verify your a/f tune. You just added a lot more air in yet did nothing for fuel. A 255 high pressure pump would be a good idea regardless.

Black Stampede · May 7, 2006

Get it tuned.

Swarzkopf · May 7, 2006

Verify your a/f tune. You just added a lot more air in yet did nothing for fuel. A 255 high pressure pump would be a good idea regardless.

Thanks, but I don't think that more fuel is the solution as the MPH significantly improved with less fuel.

Get it tuned.

That's the last resort. The closest trustworthy place to tune it is over 3 hours from here.

Anyone else?

95vert354 · May 7, 2006

Sounds to me like your not getting enough fuel. Do you have stock 19lb injectors? You went with the cobra intake, a and tb are bigger then stock cobra, but the cobra came with 24lb for a reason. You also mention a lot of wheel spin... how much more now then before? I ask that because your 60' seems to have slowed also. BTW I just saw a '03 cobra run today after he upgraded to a 2.2 ken bell SC, he lost 3/10ths from before the upgrade. he was just sick and couldn't figure out what the problem was....all the while spinning all through 1st and halfway through second..his 60' was down .35 yet his trap was up 4mph. I'd check the a/f like mentioned,and dont think f/p really made as much difference as you might think if you were having traction problems. also the no2 without the extra fuel(being a dry kit).is not going to give you the power you expect,and also be dangerous if it is in fact a lack of fuel problem.

Swarzkopf · May 7, 2006

Thanks for the response.

My 60's are really the exact same from last year to this year.

also the no2 without the extra fuel(being a dry kit).is not going to give you the power you expect,and also be dangerous if it is in fact a lack of fuel problem.

The Zex dry kit does add extra fuel while spraying- it does so by bumping fuel pressure. Like I said, I used the kit last year to pretty good success.

Thanks again.

95vert354 · May 7, 2006

Swarzkopf said:
Thanks for the response.

My 60's are really the exact same from last year to this year.

The Zex dry kit does add extra fuel while spraying- it does so by bumping fuel pressure. Like I said, I used the kit last year to pretty good success.

Thanks again.

Yes , I know the dry kit adds with f/p.. but if the 19s are alredy maxed out with all the extra air flow, is it giving it enough? somthing to think about. I think most would tell you to up them to 24s.

urban96 · May 7, 2006

how far are you from http://www.kauffmanmotorsports.com/index.html ?

Swarzkopf · May 7, 2006

3 hours and 45 minutes according to MapQuest...

I'm thinking of taking it to "PowerHouse" up in Erie, PA. I'd never heard of them until doing some research tonight, they're less than two hours from here.

At this point, from suggestions on another board, I'm going to try the following first:

-Put stock throttle body back on
-Get the plugs gapped correctly
-Run new rubber

I might rent dyno time at a local shop as well and tune (mechanically) myself.

Thanks for the replies.

94gts · May 7, 2006

95vert354 said:
Yes , I know the dry kit adds with f/p.. but if the 19s are alredy maxed out with all the extra air flow, is it giving it enough? somthing to think about. I think most would tell you to up them to 24s.

2 years ago i ran a stock motor (just exhaust), fuel system, and a holley 150 wet shot to a 13.8 @ 103

last year i ran iron gt-40's with 1.7rr's, an explorer intake, 155 lph fuel pump, and 43 psi of fuel(stock tb, maf, inj, etc). I went 12.9@ 110.

they are not stelar numbers primarily because i still had 2.73's, street tires, and used to suck at driving. but my car only went faster and faster after i added more modifications but still had the stock 19's.

if i could guess (because i never dynoed my car) i bet i made over 350 horse and way over 400 tourqe (to the wheels) with nitrous on the stock 19's

95vert354 · May 8, 2006

94gts said:
2 years ago i ran a stock motor (just exhaust), fuel system, and a holley 150 wet shot to a 13.8 @ 103

last year i ran iron gt-40's with 1.7rr's, an explorer intake, 155 lph fuel pump, and 43 psi of fuel(stock tb, maf, inj, etc). I went 12.9@ 110.

they are not stelar numbers primarily because i still had 2.73's, street tires, and used to suck at driving. but my car only went faster and faster after i added more modifications but still had the stock 19's.

if i could guess (because i never dynoed my car) i bet i made over 350 horse and way over 400 tourqe (to the wheels) with nitrous on the stock 19's

Yes, with a wet kit your getting extra fuel through the fogger nozzle off the fuel rails/fuel line. With a dry kit you have to get it through the injector. You cant make 350 hp through a 19lb injector only.this is why the cobra used 24lbs.

Killercanary · May 8, 2006

Shawn, I just replied on SCS a little while ago, but are you sure that your bottle has nitrous left in it and that the bottle pressure was sufficient? It also seems like your barely adding any juice to it. For your times to be that far off, the nitrous is the first place I'd look. It may have leaked out over winter.

94-302-vert · May 8, 2006

look at the MPH numbers.. you seem like you are spinning most of the first 1/8th mile... Go back and cut the nitrous level down and I bet you do better due to less spin...

You were definitley havign traction problems but messing with the fuel pressure was definitely helping you to get some more HP (MPH) out of it...

Swarzkopf · May 8, 2006

Shawn, I just replied on SCS a little while ago, but are you sure that your bottle has nitrous left in it and that the bottle pressure was sufficient?

I had the bottle refilled before going at Bower Hill Automotive...

The nitrous "seemed" okay when I checked it- it comes out cold and freezes what it touches, but my bottle pressure has been low. It was only at 700 PSI when I got home from the track.

Thanks for all the responses guys.

Black95GTS · May 8, 2006

95vert354 said:
Yes, with a wet kit your getting extra fuel through the fogger nozzle off the fuel rails/fuel line. With a dry kit you have to get it through the injector. You cant make 350 hp through a 19lb injector only.this is why the cobra used 24lbs.

I'm with this guy 100 percent. I would actually use 30 pounders and the stock fuel pressure, and allow the NOS to do the a/f adjustment. Don't be scared of more injector.

You might want to think about some lower control arms to help plant it.

Adam

Nagash01WS6 · May 8, 2006

It needs more injector!

Injectors are like cowbells, you need more!!!!

Especially running a 125 dry... I bet your A/F is getting up there. Is it knocking at all?

IEatRiceGT · May 8, 2006

I agree..30lb injectors would help

RaceDvr50 · May 8, 2006

Look back at 94gts said. What everyone else seems to be missing here not to be an ass is that you upgraded your mid airflow and you are completely choked at the heads. I've seen many places that the stock heads will never flow enough for an engine much over 300hp. Do you have a larger mass air? I didn't see it mentioned you should have at least a 70mm and a different set of heads. You can pick-up a set of GT40 or GT-40P's pretty cheap, the GT40P's came on some of the Explorers with 5.0's like 1997 but the GT40P's will require non-stock headers. Motorsport sells some and there are others that fit. Your engine is gasping for air most likely when you get to the top of the track and it's costing you MPH

1/4 Mile Guys, HELP. Analyze My Timeslips

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