EDIT: http://forums.maxima.org/showthread....hreadid=130933 contains my dyno results.

1st run R/T 1.077 60' 2.820 330' 7.251 1/8 10.809 MPH 68.97 1000' 13.889 1/4 16.470 MPH 87.71

5th run (fastest) R/T 1.029 60' 2.510 330' 6.733 1/8 10.243 MPH 69.58 1000' 13.298 1/4 15.863 MPH 88.27

Ran at Pacific Raceways (SIR) in Seattle, Washington. Don't know the exact weather conditions, but it was mid 80's for sure.

I ran 7 times, and my fastest MPH was 88.27. I have a 97 SE 5-speed, intake, Cattman y-pipe, RT cat, Stillen catback, STS, 18" wheels, and stereo (three 10" subs, two amps, six speakers.) I left everything in the car, ran on just over 1/4 tank of gas. I'm going to run to work real quick and weigh the car, so keep in tune for that.

The MPH is what really worries me, shouldn't I be trapping mid-90's? I didn't misshift once, didn't hit the revlimiter, nothing. The car isn't showing any dummy lights, but I should still pull the codes and see if anything comes up. I had my exhaust apart a couple days ago installing my STS and although I didn't know exactly what to look for, the flex section on the y-pipe looked ok, it definatly wasn't blocking the WHOLE pipe but it kinda looked like it could have been coming undone towards the front.

Some friends at the track told me that a 15.8 @ 88 was respectable under the weather conditions, weight of my car, and racing on my 18's, but knowing that most of you are trapping 6-7 mph higher than me worries me a lot.

I'm taking the car to the dyno Monday morning before work so I guess that will tell the truth, wether I just suck at teh racing or if I really need to get something fixed.

Should I dyno on my 18's, or should I put my stock 15's back on?

Thanks for the help, I'm pretty at the times.

EDIT: Weighed my car, 3220 without me, and with about a half tank more gas than I raced on. The car had new spark plugs, new belts, flushed tranny fluid all on Christmas Day, and I just changed the oil on Wednesday of last week so I know it's not regular matinence.

 

i think the next time u go to the track u should remove unecessary items....like ur subs and run on ur 15s
then u can compare ur times, cus i think u should be a lot faster..plus u need to work on ur R/T and 60'

sorry but i dont know anything bout dynos

 

Yes, get rid of the "dead weight".

 

I dont think the weight is that much of an issue. I raced last night and my car is very similar to yours. Mine weighs in at 3200 lbs, WITHOUT me in it. I have 2 15" subs, 3 amps, but I do not have 18s. I also have a 97 SE 5 speed with the same mods almost (see my sig). Last night the temps ranged from 89 to 69 degrees, yet I was still running consistent 14.9, 14.8 14.8 and then 14.7.

1) You gotta launch harder. 2.5 and 2.8s are very slow. 2.2 and 2.3s seem to be the everage here.

2) Yes your MPH is way low, which means your car isnt making the power it should be. Check the flex section, check the tightness of spark plugs and check for the 0304 code. When I was trapping 88 mph before, it was a combination of blown flex and loose spark plug. I average 93 mph at the traps, which is still low compraed to others. I still havent figured that one out.

 

Thanks, Eric. That is the kind of reply I was looking for, and I will definatly check into that stuff in the morning.

I edited my first post with more info.

 

One other factor could be: If your spinning a lot in first, then short shift into 2nd (to stop the spinning) you could be bogging the car. I don't know if this is happening but in one of my old cars I found that to be my problem.

 

I would be looking into those wheels. Go do a run with your stockers if you have them and compare. If that doesn't fis it, then I imagine you have a performance issue.

I ran a 16.00 with a trap of 89.97 MPH in my auto GLE with nearly a full tank of gas and no weight reductions. The only mod i have is the intake in my sig.

 

Actually, weight is somewhat of a factor in your problems. Figure this. If each of your subs weighs about 15 pounds, multiply that by three, thats 45 pounds. Ok, now for your box. How much does that box weigh if it is at least 1/2"-3/4" thick MDF board. That has to be an extra 60 pounds. So, round it off, you have an extra 100 pounds at least in your trunk. This is bad for our setup since whenever you accelerate hard, our engine lifts up and the weight of the car is shifted to the rear. With this extra added weight, the rear is now shifter farther down, which will take a bunch of traction away from your front wheels.

Now about your rims, they will also play a large factor as well. Those are some big, heavy rims. Now your transmission will "turn" them at a decent speed, but because of the heavy rims, it can not turn them as fast as it could if they were say, 15 inch steel rims (ie. hubcap wheels). Those steelies will be at least half the weight of your rims. So, with the steelies on, your transmission will be able to turn the wheels at a much more efficient rate with increase acceleration.

Another issue, where are you shifting the vehicle at? For "most" Maximas, there are some very specific optimal shift points. Here is the "general" shift points for most Maximas with the usual mods. These numbers are when to shift when in that gear, say from a stopped position.

1st-6400 or 6500 RPMs
2nd-6300 RPMs
3rd-6200 RPMs
4th(if you make it there)-6000 RPMs

The reason behind this "theory" is based on your TQ (torque) curve, like on a DYNO. At about 5500-6000 RPMs, your TQ will top out, and anything after that is basically wasted time at WOT. But, you will need to continue on past this point so that when you shift into 2nd, 3rd, etc., you will fall right back into the middle of the TQ curve and you will continue to pull even more. Remember, HP does not give you acceleration, TQ does.

With these factors in mind, you need to re-think about taking out the dead weight and by dynoing your car, you can find those optimal shift points that are best for YOUR car.

 

heh, my highest top speed was at 90 mph last week, and I JUST got in the Y and such, but I was making 60' times like 2.6 because of lack of traction (I have the worst tires you could imagine...don't ask), so I'm not surprised I didn't get up there.

edit: however, I was running lower 1/4 times... 15.5's consistently. I wanna get out of the 15's badly.

 

it has nothign to do with weight.. look at his 60ft.. 2.8 and 2.5

if you get a 2.8 at 16.5.. with the right math.. you are looking at... 1.6 off so thats .. 14.9 at 2.0 60 ft.... and a 2.5 at 15.8 .. you are looking at 1 sec off.. which is 14.8.. you just need to learn how to launch.. and slip the clutch..

as eric said.. its not a weight issue.. its a launch issue.. you are looking at 14.8 / 14.9 which is pretty good..

 

But regardless, shouldn't my trap speed have been higher than a consistant high 87mph-low 88mph 7 times in a row? I agree I need to learn how to launch still

 

^^^

 

Weight does play a bit of a factor, but the wheels and poor 60' are probably the biggest factors. The thing is though, I can still pull off 14.9s@94mph with high 2.4s. I think he needs to look over his car and make some runs without the wheels, stereo, and different shift rpms.


Dave

 

He? You mean me? Thanks Dave, I know you are very active at the track and I was really hoping you would reply. I will definatly be removing my wheels and anything non essential before I hit the track next time, but the stereo is difficult...my two amps are mounted on the back of the box, so if I remove the box, I have no stereo, nothing...I gotta get those amps moved

Doesn't the 88mph trap seem low, even with my wheels and extra weight? That is what concern's me the most, I know I can improve the rest thru practice.

 

Dave have you ever got your car weighed? Reason why I ask is I know you have a 96 and those tend to be lighter then the 97-99s.

globalthreat: Hows your shifting? If you shift slowly during the drag thats gonna slow you down both MPH and time wise. But I would still check that flex section make sure it isnt blown. Have you ever dyno'd?

As far as rotational mass is concerned, I thought about doing the lightened flywheel mod, and underdrive pully but the flywheel is expensive and the underdrive would underdrive my stereo. I dunno.

 

Like I said in the beginning, get rid of the dead weight....ie. wheels and stereo. And try shifting at different RPMs. Thanks Dave....

 

My shifting is fine. I won't say perfect because I have nothing to compare to, but with my short throw shifter it takes me no time at all to flip into the next gear.

I just got my car dyno'd, I just got home. Max HP was 166.8 @ 5500 RPM, and max TQ was 177.6 @ 3300 RPM.

I will make another thread about my dyno and edit my first post and put the link there.

 

Eric-
I got my car weighed a long time ago, but I don't remember the exact numbers. I want to say it was something like 3050lbs or something with a fair amount of gas. I think the scale you weighed on was wrong because there's no way your 97 weighs 3200lbs unless you have a 100+ sub box in the back.

Global-
I should add that my first few times to the track weren't impressive at all. I had drag racing experience in my old Z28, but never with FWD. With a y-pipe, intake, muffler, and a 46lb 17" combo I was getting consistent 15.5-15.6s@89-90mph in 80+ degree weather. This was with the spare and very little gas too. My 60 foots were in the 2.4-2.5 range. I added a B-pipe, UDP, stock muffler, lighter rims, and much better driving and shifting and my times dropped significantly and my trap speeds went up, especially in cooler 50-60 degree weather.

Put the stock rims back on. Don't get greedy on your launch. Rev up to 2500 and slip the clutch while feeding it gas. Experiment and see if you can get 3500rpm launches with 2.2-2.3 60 foots. Never dump the clutch. Pull out as much weight as you can and run a 1/4 tank of gas. Shift the 1-2 at 6500, 2-3 6300, and 3-4 at 6000 (regardless where you are at the track). Try running in cooler weather and ice your intake manifold. For every .1 you shave in the 60', you'll see about .15-.20 drop in ET and a gain of about 1mph. Most 5 speeds with a intake, y-pipe, exhaust, decent weight rims, and decent weather are in the 14.9@93mph range. Shoot for that.


Dave

 

Dave -

The scale is correct It measured my weight exactly, and it is used hundreds of times a day to weigh semi trucks and trailers, so it has to be accurate. And yes, my first post said that I have a box and three subs in the trunk I also ran on my heavy 18's...I guess it all adds up.

 

Ahh but I DO have 100+ pounds of stereo equipment. 2 15" woofers and 3 amps. The optima battery felt heavier then the stock battery as well. That and the 97s are naturally heavier then the 95-96s because of the added steel under the bumpers (see crash tests). I wonder how much the sunroof and the motorized seats add. I also had 1/2 a tank of gas. That and I dont bother to clean out my car.

 

Suuure, blame the mcdonalds bags and taco bell wrappers!