Went to the track...Low Trap Speed???

[Rock777]

I went to Gateway last night, which later checked and DA was ~1500. My mods are in my sig. I was expecting to trap around 105-109, or abouts. My car is untuned, which I'm hoping is a key factor. Launches went good for street tires, didn't miss any shifts, shifted at about 64-6500 first two runs, then raised it to 67-6800 to see what would happen. Didn't go to 7k only because it's the 03 motor, which on dynos peaks lower from what I've seen, let me know if it's not true. Didn't feel any misses, felt real smooth, but something is def. up. Here are the slips:

Run #1

60' 2.11
330' 5.889
1/8 8.955
mph 80.19
1000 11.605
1/4 13.827
mph 101.45

Run #2

60' 1.98
330 5.734
1/8 8.812
mph 80.03
1000 11.463
1/4 13.697
mph 100.40

Run #3 (shifting at 67-6800)

60' 2.014
330 5.770
1/8 8.854
mph 79.98
1000 11.507
1/4 13.736
mph 101.14


For now, I'm mostly concerned with the trap speed. This is what the pile should be running stock, what the?!?! I'm thinking it either has to be in the fuel pump getting weak and not giving enough juice in the upper R's, or it just needs a tune real bad. I am planning on getting it dyno tuned eventually, but wasn't planning on it this soon cause of $$.

But is it feasible that a tune add 5mph to my trap?
Will a custom order tune from Jon Lund, Anderson, Amazon, etc. make a difference?
If I bought a used, but unlocked SCT for a good deal, can you buy custom tunes that they send you.

Any suggestions/ comments welcomed.

 

[90goldtsiawd]

I wouldn't be driving that car whatsoever until you get it on a dyno. You're asking for trouble. Does this car have the blower on it? I don't understand how people can dump money into a car in mods to make it faster and think it's too expensive to get it tuned? THAT'S THE MOST IMPORTANT MOD!

 

[Rock777]

I wouldn't be driving that car whatsoever until you get it on a dyno. You're asking for trouble. Does this car have the blower on it? I don't understand how people can dump money into a car in mods to make it faster and think it's too expensive to get it tuned? THAT'S THE MOST IMPORTANT MOD!

If it was blown I wouldn't be driving it without a tune, but it's not. My sig. says '03 Longblock, ported 01 intake. I agree a tune is important, ESP. on power adder cars, but on N/A it's not as detrimental and therefor was waiting til I have all the bolt-ons I want on. At this point I do and a tune was the next mod in order, was just going to wait a few months yet....Well, before the frustration hit last night. LOL

 

[LitleWhiteSnake]

I think it's kinda right. Low comp motor with no blower is a pig.. But a tune will help out alot, I need one too

 

[Rock777]

I think it's kinda right. Low comp motor with no blower is a pig.. But a tune will help out alot, I need one too

Yeah, you're right, 8.5/1 sucks N/A. But I would think the 03 heads and rest of my bolt-ons should easily compensate for that and more. My 99 with much less still at least trapped 106-107. I wouldn't even care if my E.T. was the same, long as my mph was higher. 100mph?!?! that's disgusting for a bolt-on 4v :bash:

 

[whtcobra1998]

Yeah, you're right, 8.5/1 sucks N/A. But I would think the 03 heads and rest of my bolt-ons should easily compensate for that and more. My 99 with much less still at least trapped 106-107. I wouldn't even care if my E.T. was the same, long as my mph was higher. 100mph?!?! that's disgusting for a bolt-on 4v :bash:

haha yeah but your still low compression, cant even compare it to a stock motor let alone you added 100lbs more to the front, even after your "bolt ons". you could be like me and run 12.5@128mph, slow time but high speed

 

[Wynn]

I haven't had my car to the 1/4 mile track yet, but your 1/8 mile ET/ MPH is right on par with what mine runs without the spray. The heat and humidity could have played a part as well.

 

[goat-ee]

Between the compression and lack of tune, sounds about right. Don't under estimate the tune. If your still running the stock 97 tune, it has got be throwing codes. And if one of them is for the IMRC's, which it should be, it's pulling the living hell out of timing. And yes, in your case I would absolutely not be afraid to buy an UN-LOCKED SCT 2 and get a good mail order tune. I got mine from lasotaracing.com and couldn't be happier. And one more time, the compression is kicking your a$$ pretty big also, I believe it's in the range of 10% loss of hp for every point of compression loss. So in your case (assuming a 320fwhp engine) your probably losing over 45hp just due to that alone!!!

My calculator says that your at 290fwhp as is, based off you traps. The calculator also says that you need 345fwhp to make 108mph trap. So assuming 45hp for the compression and I would bet another 20 or so for the lack of tune (especially for the lack of imrc's). That would add up to 355fwhp, almost exactly where you should be!!!

Solution, get a tune on it and get a 103-104mph trap or better yet, throw an Whipple or turbo (not a centri) on that f'er and kick some a$$!!! Otherwise, accept that the engine is doing exactly as it should for what you have done with it!!

 

[Rock777]

haha yeah but your still low compression, cant even compare it to a stock motor let alone you added 100lbs more to the front, even after your "bolt ons". you could be like me and run 12.5@128mph, slow time but high speed

Yeah, those two things def. have an effect. I hear what you're saying about slow time and high speed too, that would be equally as frustrating I think.

I haven't had my car to the 1/4 mile track yet, but your 1/8 mile ET/ MPH is right on par with what mine runs without the spray. The heat and humidity could have played a part as well.

I guess that's good and bad to hear. Good, because it helps ease the thought that maybe something's off, besides a tune of course. Bad because, well I just can't accept 100mph. ha

Between the compression and lack of tune, sounds about right. Don't under estimate the tune. If your still running the stock 97 tune, it has got be throwing codes. And if one of them is for the IMRC's, which it should be, it's pulling the living hell out of timing. And yes, in your case I would absolutely not be afraid to buy an UN-LOCKED SCT 2 and get a good mail order tune. I got mine from lasotaracing.com and couldn't be happier. And one more time, the compression is kicking your a$$ pretty big also, I believe it's in the range of 10% loss of hp for every point of compression loss. So in your case (assuming a 320fwhp engine) your probably losing over 45hp just due to that alone!!!

My calculator says that your at 290fwhp as is, based off you traps. The calculator also says that you need 345fwhp to make 108mph trap. So assuming 45hp for the compression and I would bet another 20 or so for the lack of tune (especially for the lack of imrc's). That would add up to 355fwhp, almost exactly where you should be!!!

Solution, get a tune on it and get a 103-104mph trap or better yet, throw an Whipple or turbo (not a centri) on that f'er and kick some a$$!!! Otherwise, accept that the engine is doing exactly as it should for what you have done with it!!

goat - all valid points you have made. Only thing I'm hoping you're wrong on is being at 290fwhp, which is roughly 246rwhp. I can see how a calculator would get that though, I just sure as heck hope after a tune I'd be at least 270rwhp. Even though that doesn't impress me on paper. I'm definitely looking into a used SCT X3 and have already contacted an area shop to bring it in for a dyno tune in the next couple weeks hopefully. We'll see what happens....

Thanks guys for the input, it's really appreciated.

Any other comments welcomed...

 

[PSUCOBRA96]

our power def. isnt good esp since you are running it through with 4.10's, the compression isnt helping but I am sure the tune is killing power from strat to finish, I assume that will solve most of your issues.

 

[Toasty]

I went to Gateway last night, which later checked and DA was ~1500. My mods are in my sig.

8.5:1 compression? And you're worried about track performance? Seriously?

 

[Toasty]

goat - all valid points you have made. Only thing I'm hoping you're wrong on is being at 290fwhp, which is roughly 246rwhp. I can see how a calculator would get that though, I just sure as heck hope after a tune I'd be at least 270rwhp. Even though that doesn't impress me on paper. I'm definitely looking into a used SCT X3 and have already contacted an area shop to bring it in for a dyno tune in the next couple weeks hopefully. We'll see what happens....

Thanks guys for the input, it's really appreciated.

Any other comments welcomed...

A stock C headed 99-01 cobra makes maybe 260 RWHP bone stock. You have longtubes, and a rai plus a alum flywheel (less parasitic loss). HOWEVER you have a full point and a half less compression, so you arent making much more than 250 RWHP IMO. On top of everything else, the forged components (rods and pistons) in the 03 shortblock weigh noticeably more per piece than the sintered metal rods and hypereutectic pistons in the stock 96-01 engines, so your reciprocating mass is probably the same with the alum flywheel or possibly heavier.

Put it on a MD or Dynomatics dyno and see what it makes for peak power and what the power curve looks like.

 

[cmr98cobra]

Are you planning on adding a super/turbocharger? If not, that thing will always be a pig. 8.5-1 compression just isn't going to work N/A. I'm shocked your number are as good as they are.

 

[Rock777]

Are you planning on adding a super/turbocharger? If not, that thing will always be a pig. 8.5-1 compression just isn't going to work N/A. I'm shocked your number are as good as they are.

Yeah, I plan to make it whine someday, but it won't be real soon. Which is why I want to get what I can out of it now. I'll get a low 13/high 12 out of it N/A yet this summer. :cuss:

 

[Rock777]

I got the car dyno tuned today and was overall a success. It peaked at 288/288 in 95 degree heat with a 105+ heat index. It was running super rich when I brought in, A/F was 10.0/1. I think it peaked at 267/273 straight off the road (I don't have this graph though). Overall, I gained quite a bit under the curve though compared to my base pull, one area I gained 36hp. My curve is funky though, as you can see. The torque drops quickly after 5200, where it peaks while the hp stays almost completely flat from about 5200 all the way until he let off. I'm not sure if this is normal for these motors or if my combo is attributed to this.

Comments welcomed.....