03 G sedan A/T- 105k miles. I currently have the old ECU which limits my mod improvements. I'm the original owner and drive it really hard, but I take great care of it. I have done some mild bolt-on mods that on paper should have yielded me 30-40 hp- but at the track (1/8th mile) my times have not improved- technically slower- I didn't pull a single sub 10 sec run last Saturday night (on 20" wheels though)- which I had previously done before a plenum spacer and cat back system. I know those mods don't help off the line, and are more of a mid/upper rpm benefit- but I expected some time improvements. The mods just aren't translating to better times on the track. My car wants to rev higher and is still pulling strong when it shifts.

What am I doing wrong? What can I do to gain performance or untap the power of the mods I have already made?

Thanks.

 

what mods do you have?

 

Maybe it's that new Nismo Aero kit slowing you down. . . (LOL, Just Kidding Jeff!)
Looks great though!
GL!

 

30-40hp seems like a stretch for mild bolt-ons and probably not enough to make a significant difference in your times. Compare your DA from previous runs as well, maybe it was just a bad air night.

 

Unless you're doing ricer math (not making fun, it's just the simple addition of what each boxed product SAYS it will give you)

Take your 20s off for one because I can bet you they weigh 40lbs each, that plus your tires is going to hit just under 80lb. Go back to OEM wheels and you'll have dropped 15 lbs per wheel. That's 60lbs. Pull out your spare tire and take off as many little things as you don't need! Also I'm assuming you're probably trying to shift in Manumatic, don't it'll slow you down, shift it into manumatic 5th and just let it do it's work.

Other than that, you should have bought an STI.

 

engine performance mods, in no particular order:
motordyne 9/16 plenum spacer;
z-tube;
Drop in K&N filter;
aluminum underpulleys;
borla 2.25 cat-back;
10 wire Grounding Gear grounding kit;
(headers sitting in my garage )


I think that's it for the motor mods.

 

....just a random interest....where did u get that grill buddy and how much did you pay if you remember?

is it gailla godzilla gorilla gialla?

 

Were you in drive? Did your brake tourqe?

 

So basically your car is probably making about 16whp/16wtq more than stock with those mods. The headers will add another 5-8whp/wtq. The single most important mod you can do right now is dump the 20" rims. They're sucking out the equilivant of 20+whp.

What is your ET, MPH, and 60', before and after? Were all before and after runs on 20" rims? Were all runs at the same strip. What were the conditions for the before and after runs? Cool crisp air will allow your car to make significantly more power than a hot humid day. Just a 15 degree difference has an effect on an NA car.

 

oh yeah, the grill. . . i was expecting at least 10-12 hp on that mod too

$150 shipped.
found the grill on e-bay- http://cgi.ebay.com/ebaymotors/ws/eB...OU%3AUS%3A1123


Buy the grill at your own risk!!! plan on doing a lot of the work yourself or paying someone a small fortune to do it right. having said that, given my recent experience with aftermarket fiberglass products, it was exactly what I expected to receive. shipping was a bit slow- ships from Hong kong. proceed with the grill at your own risk. i could easily see someone ruining it during prep if they don't know what they are doing. Would I do it again? Hell Yes!!!! Just look at that sexy grill!!

you can expect typical fiberglass, poor fitment, poor quality, requires hours of prep before paint and fitment can take a while. i'm still not 100% satisfied with the fit, but nobody else has noticed until I point it out. The finished product came out alright and I am pleased. i have always loved the look of the grill and G35Papa's ride was my inspiration- but i didn't want to try and clone his ride. i previously had an OEM blackout grill, with painted black bezel OEM headlights, i was embracing my 03's black lower sills!! But those F-ing sills were hard to keep looking good!!!

It is a rare grill on the sedans- dime a dozen on the coupes.

BTW, i never ever thought these words would come out of my mouth, but due to my new aero sides, "I think my car would look good with mud flaps!!" There, i said it, in writing, for all the world to see. my kids are right, I'm getting old

 

Borla. It really needs an X pipe to really be complete. Trust me.

And you really need an tune from Technosquare to wake up your motor. Trust me I know.

You have a nice mod list though. Love the grill.

If you really have 20s, then you just added a ton of weight (relatively) and it really hurts your 1/8 mile time. Try it with your stock 17s.

 

I expected more than 16 hp for the mods. I have modded other cars in the past, and know that some mods are synergistic with each other (for example: say a Z-tube gives you +3 hp, and a K &N drop in gives you +3 hp, but when you do both, you get 9 hp, I made all those numbers up- it's just to illustrate. I don't actually know if that combo is synergistic, but intuitively it seems likely), other mods are merely additive and the additive can vary due to other mods. Some mods can cancel each other out. Some are counter-intuitive- should improve performance in theory, but actually decrease hp or performance. (See test pipes vs. stock cats with a cat-back system*) *Source Robert at S&R performance, with dyno results to prove it. Without FI I don't believe I will see but 2-3 hp with headers- not worth the time and effort.

Yes, the 20's are like towing a trailer, but my son swears I had my 20's on last time I ran. Both trips to the track were last minute decisions, otherwise I would have thrown on my 17" 350z wheels. I am pretty sure both runs were on the same 20" wheels and tires, so I believe we are comparing apples to apples in that regard. I am going back this Wed nite with the 17's. I'll let everyone know the performance drag of 20's in an 1/8th mile. Rotational mass being what it is, and my 20's weigh a ton- (definitely for show, not go!) and logically the launch would be the most effected aspect of running the 20's. I understand basic physics, but cannot do the calculations. Engineers feel free to chime in and help here. I will weigh the 17's and the 20's later when I swap.

Same track, same rims. I never raced my car at the track while it was bone stock, so I have no stock baseline. The car has never been on a dyno. First timed runs were in June 2009- Clearwater Florida. this past Sat nite was unseasonably warm and humid, but would have defintely been cooler and less humid than June. Ambient air temp within 5 degrees, humidity diff unknown for certain, but typically June is way more humid than Oct, even when we have a 90 degree Oct day. Yes, Sat high was 90 degrees here.

For the June 09 runs I believe my only mods were the K&N drop in filter, Z tube and aluminum underpulleys. New untimed mods were plenum spacer, catback, grounding kit and changed Spark Plugs from original stock to Denso IKH20 (cooler -2). Always premium fuel.

My 60' and 333' splits were clearly faster before the spacer, cat-back, etc. Overall ET time averaged about the same, but I had no sub 10 sec runs this Sat night. I did leave my VDC on this time and in the past I had turned it off- probably not the best choice given the 20's. Probably better to let them spin and hook given the increase in rotational mass with 20's. The VDC very well may be the difference in the reduced launch speeds. So basically in a race between my pre mod and post mod car would see the pre-mod jump out to an early lead with the post mod car running it down and nearly tying at the finish.

Gearheads- what rear end final drive will give me the fastest launch given my current set-up and A/T? 3.7 or can I go 3.9 with a stock J30 rear diff? Is the J30 a direct swap or do I need to crack the stock G case and swap the gears?

tx

 

Yes, brake torque with launch in 1 then slap to D after it hooks. VDC left on most recently. Previously ran with VDC off but tire spin seemed excessive. However, the tire spin probably helped off-set the effect of the 20's which would explain the faster split times I had before. The more I think about it, the VDC on may have been the difference in my launch. Engineers, I know you are out there.

ECU limitations make tuning more difficult on the early 03's. My ECU has only been reset, never tuned.

the engine clearly would like to rev higher, if it were a manual with no limiter my guess is at least another 800-1000 rpm no problem.

 

Why are you launching in 1 then going into D? Stay in MM. Turn VDC off, not only does the brakes engage your engine gets cut = sh!tty launch. 1/8 of a mile is all about the launch.

DaveB has said that staying in D for the launch untill it shifts then going into MM for the 2-3 shift(1/4 mile). Since he said that in MM there is some torque management that goes on, that does not in D. but in a 1/8 mile I noticed slower times doing the D launch. Staying in MM gave me the best and most consistent times.

 

Yeah like mentioned earlier the VDC should be off when you race. It will kill your launch. Practice launching by using a little brake torque effect. You will get it dialed in after a few attempts.

Also if you are dong mods for performance on an automatic, have you considered doing a valve body upgrade and possibly a high stall torque converter while you are at it? You mentioned gears and those would help. Those three mods will show the biggest gains at the track.