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Discussion Starter #1 (Edited)
This is my first post on this forum, I apologize if I make any errors.
Re: Infiniti G35 coupe 6 sp manual, Borla exhaust, Greddy turbo.
I have a 2003 g35 coupe with the Greddy twin turbo and intercooler setup
installed. From a roll, the car runs like a rocket. I tried two passes at the dragstrip near Hattiesburg, Miss. and I could not get away cleanly from the
start light. I experience violent wheel hop in 1st and 2nd, then the car settled down after about 100 feet, my 60 ft. times were terrible but my trap speed was 105 and 107 respectively. I turned 14 flat, which is a stock time with a faster trap speed. Here is the question, there is an on off swith called vehicle dynamics control, this is always on as default, it must be switched off by the dash off button. I think this is for slippery roads and not only switches power to the opposite wheel, it also applies the brake on the slipping wheel. I have not had time to confirm this. My main question, and I have not tried yet. Does this off switch turn off positraction ? Would you
believe the mechanics at the Infiniti dealership nearby do not have a clue ?
I would appreciate any advice. joerx [email protected]
 

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ZPOOLNZ
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Wait so you do not turn VDC off when you go down the track? It is a traction control system plus; not only does it control the throttle, but it controls the brakes. It is made to keep drivers from killing themselves on the streets. It doesn't turn off "positraction" you have an LSD the computer does not control that. If your trying to race with it that is one of your problems (though you wouldn't be suffering from wheel hop). How wide are your tires? You have IRS welcome to the world of wheel hop. Do you want the car to be a drag car that launches well, a car that is well balanced, or a car just set-up for handling? Because your suspension set-up needs to be built along one of those lines. One thing is invest in some lightweight 16s or 17s that are wide enough to fit some decent size DRs on (265 or 275 or so).


I would recommend before doing anything to a car know more about it. Your lucky you haven't destroyed your G35C yet. Take time and research; get to know your car before you modify it or attempt to race it.
 

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One thing that maybe cure the wheel hop is to install urethane bushings on the main rear subframe attachment points. It helps on the Z32, so it may help here as well. Coilovers may help, as well as stiffer rear shocks.
 

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Discussion Starter #4
I think you are correct on shocks and coilovers but

♣Zen31ZR♣ said:
One thing that maybe cure the wheel hop is to install urethane bushings on the main rear subframe attachment points. It helps on the Z32, so it may help here as well. Coilovers may help, as well as stiffer rear shocks.
What I did not realize before I tried the car at the strip, is both on Z cars and G35s is an electronic computerized device that must be shut off to race. It is called Vehicle dynamic control. It is on by default and a dash button shuts it off. Another member of this group, and I hope he is correct, posted me that the positraction stays active. The VDC, when on, not only transfers power to the other wheel, but applies the brake to the slipping wheel. I hopped down the track like a rabbit for all of 1st gear and part of 2nd till it settled and the final trap speed was 105 and 107 respectively. That should be good for low 13 s. I turned 14 flat. But, I was ignorant at the time, and think I have it solved, and thanks for the advice on suspension. I also need wider tires, I have 235s and probably need 275 or 285.

joerx
 

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ZPOOLNZ
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If you want to run at the track you need DRs. 235s are not wide enough to launch on. The VDC will basically shut the car off and modulate the throttle when the tires break loose. If you are not experiencing wheel hop if VDC is active you are experiencing throttle modulation by the computer. Also learn to drive; your biggest problem is your driving ability at this point. Even though I don't personally know you I can tell that if you are having problems in 1st and 2nd you need to work on your launching and driving techniques.
 

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Discussion Starter #6
driving techniques--you are correct but

JAMESZ said:
If you want to run at the track you need DRs. 235s are not wide enough to launch on. The VDC will basically shut the car off and modulate the throttle when the tires break loose. If you are not experiencing wheel hop if VDC is active you are experiencing throttle modulation by the computer. Also learn to drive; your biggest problem is your driving ability at this point. Even though I don't personally know you I can tell that if you are having problems in 1st and 2nd you need to work on your launching and driving techniques.
JAMEZ
You are correct, with only two passes, I need to work on launching, I have
not been to the drags in years, and practice is important. Remember you are the first person that had the real knowledge of how the VDC works, everyone else I have contacted were not sure or didn't know. But I assure you once this is solved, after 3 or 4 good runs I will have it down. In 1987 I had a Buick T type (white color version of black Grand National) With the V6 turbo and extensive engine mods this car ran in mid 12s and still was streetable with working Air Cond. Only down side had to use leaded fuel and buy O2 sensors by the doz. At any rate, I am an older guy and was a Jet Mechanic in Air Force, and we messed with our cars when off duty. I am rusty at the drags, but I got the urge to try this recently. I plan to get the tires you recommend and also Eheim makes a performance set of shocks I plan to look at. If it runs in low 13s I am happy, and the car is very streetable, with a somewhat rough ride. I live in suburb of New Orleans, and I promise you cannot find a city with worse streets. Fuel economy is bad, as injectors with kit are quite large.
Again, thanks for the information. Any other thoughts, I am looking for advice.
Thanks, joerx
 

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joerx said:
JAMEZ
You are correct, with only two passes, I need to work on launching, I have
not been to the drags in years, and practice is important. Remember you are the first person that had the real knowledge of how the VDC works, everyone else I have contacted were not sure or didn't know. But I assure you once this is solved, after 3 or 4 good runs I will have it down. In 1987 I had a Buick T type (white color version of black Grand National) With the V6 turbo and extensive engine mods this car ran in mid 12s and still was streetable with working Air Cond. Only down side had to use leaded fuel and buy O2 sensors by the doz. At any rate, I am an older guy and was a Jet Mechanic in Air Force, and we messed with our cars when off duty. I am rusty at the drags, but I got the urge to try this recently. I plan to get the tires you recommend and also Eheim makes a performance set of shocks I plan to look at. If it runs in low 13s I am happy, and the car is very streetable, with a somewhat rough ride. I live in suburb of New Orleans, and I promise you cannot find a city with worse streets. Fuel economy is bad, as injectors with kit are quite large.
Again, thanks for the information. Any other thoughts, I am looking for advice.
Thanks, joerx

WHOA WHOA WHOA NOW!

I live in Luling roughly 15 minutes west of you!

Where did you take it? Donaldsonville?

Hit me up on AIM or MSN

AIM : skddestroyer

MSN : [email protected]
 

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Discussion Starter #8
♣AsleepZ♣ said:
WHOA WHOA WHOA NOW!

I live in Luling roughly 15 minutes west of you!

Where did you take it? Donaldsonville?
No I went to the track near Hattiesburg MS. I plan to go to Donaldsonville when I get some decent tires. I live in Metairie. I know Luling well, a cousin lived there years ago before it was hardly built up.

I would like to keep in touch, since you seem to know more than all of the contacts I have made concerning this problem.

I notice you rather not receive private emails, but would like to keep in touch through this forum. If you want to email me, my email is [email protected].
thanks joerx
 

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check my last post

do you have aim or MSN?

After you have had your account for 2 days you can private message me through the forums.
 

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Discussion Starter #10
♣AsleepZ♣ said:
WHOA WHOA WHOA NOW!

I live in Luling roughly 15 minutes west of you!

Where did you take it? Donaldsonville?

Hit me up on AIM or MSN

AIM : skddestroyer

MSN : [email protected]
I sent error on Buick, it ran mid 10s.
This Saturday is a big I think Chevy shoot out at the Hattisberg track, I cannot go need to work. I am not sure if is Chevy, but the track is closed and only for spectators. I forgot the name of the track, but well run, good surface, and well operated.
joerx
 

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joerx said:
I sent error on Buick, it ran mid 10s.
This Saturday is a big I think Chevy shoot out at the Hattisberg track, I cannot go need to work. I am not sure if is Chevy, but the track is closed and only for spectators. I forgot the name of the track, but well run, good surface, and well operated.
joerx

Still haven't said if you have MSN or AIM. But either way I have to get off for the night. But I sent you an e-mail hit me up again tonight or tomorrow.
 

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ZPOOLNZ
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joerx said:
If it runs in low 13s I am happy, and the car is very streetable, with a somewhat rough ride.
It should be deep in the 12s with your mods. And maybe even high 11s with some DRs. How would it not be streetable? All the kits are made for street cars; I have never heard someone complain about the ride especially in a G35C. Just remember next time RTFM!
 

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Discussion Starter #13
♣Zen31ZR♣ said:
One thing that maybe cure the wheel hop is to install urethane bushings on the main rear subframe attachment points. It helps on the Z32, so it may help here as well. Coilovers may help, as well as stiffer rear shocks.
I was advised to first try a set of eheim shocks, and if that does not solve the problem, it is thought they might do the job, then try other options, this car rides rather hard now, so I hate to make it uncomfortable to be street driveable. What do you think. Any knowledge about eheim shocks. By the way, I do not see Koni shocks mentioned anywhere, they used to be real popular.
 

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Discussion Starter #14
DR questions Nitto or ??

JAMESZ said:
It should be deep in the 12s with your mods. And maybe even high 11s with some DRs. How would it not be streetable? All the kits are made for street cars; I have never heard someone complain about the ride especially in a G35C. Just remember next time RTFM!
Nitto makes a tire very close in size, maybe 1/2 inch taller, and that should not cause any problems, what other brands should I look at ?

Previously I only raced with slicks, but the cars I had could handle them, Slicks on this car, I am pretty sure, will certainly make other parts fail.

The stock clutch and pres. plate have not failed yet, but a lot of companies advertise heavy duty street and strip. Also any advice on brands.
thanks,
joerx
 

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joerx said:
Nitto makes a tire very close in size, maybe 1/2 inch taller, and that should not cause any problems, what other brands should I look at ?

Previously I only raced with slicks, but the cars I had could handle them, Slicks on this car, I am pretty sure, will certainly make other parts fail.

The stock clutch and pres. plate have not failed yet, but a lot of companies advertise heavy duty street and strip. Also any advice on brands.
thanks,
joerx
Well a 1/2" taller wouldn't be a problem as in fitment but it's going to make your speedo be about 5-7MPH slow.. Which means if your going 70 your really going 75-77MPH..

How much boost are you running? Can't be too much if your stock clutch is still holding.
 

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joerx said:
I was advised to first try a set of eheim shocks, and if that does not solve the problem, it is thought they might do the job, then try other options, this car rides rather hard now, so I hate to make it uncomfortable to be street driveable. What do you think. Any knowledge about eheim shocks. By the way, I do not see Koni shocks mentioned anywhere, they used to be real popular.
Koni still does coilovers, as I recall. At any rate, what you need to do is reduce the play inherent in an IRS, by removing some of the weaker rubber subframe and suspension bushings and replacing themn with urethane. It won't necessarily make it ride harder, but it will reduce the bodies isolation, and you will hear more road noise. A somewhat harder ride is a small price to pay for better launchability, in my opinion. Gotta take the bad with good. Drag racing in particular is a sport where you cannot "have it all". Some things must be sacrificed in the name of performance.
 

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joerx said:
Nitto makes a tire very close in size, maybe 1/2 inch taller, and that should not cause any problems, what other brands should I look at ?

Previously I only raced with slicks, but the cars I had could handle them, Slicks on this car, I am pretty sure, will certainly make other parts fail.

The stock clutch and pres. plate have not failed yet, but a lot of companies advertise heavy duty street and strip. Also any advice on brands.
thanks,
joerx

Haven't heard from you in a couple days, e-mail me back...
 

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Discussion Starter #18
♣AsleepZ♣ said:
Well a 1/2" taller wouldn't be a problem as in fitment but it's going to make your speedo be about 5-7MPH slow.. Which means if your going 70 your really going 75-77MPH..

How much boost are you running? Can't be too much if your stock clutch is still holding.
Can only safely use 7lbs boost with stock pistons and connec. rods. Have seen others have connec. rods fail at 10lbs boost. I do not think I will change connecting rods and pistons-too much work, and too much down time to pull engine.

I still am asking if turbo car will show proper hp on dyno. I dont think since air does not pass thru intercooler. What do you think. Thunder racing in Baton Rouge charges $90.00 for two pulls. What do you think ?
joerx
 

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Discussion Starter #19
♣Zen31ZR♣ said:
Koni still does coilovers, as I recall. At any rate, what you need to do is reduce the play inherent in an IRS, by removing some of the weaker rubber subframe and suspension bushings and replacing themn with urethane. It won't necessarily make it ride harder, but it will reduce the bodies isolation, and you will hear more road noise. A somewhat harder ride is a small price to pay for better launchability, in my opinion. Gotta take the bad with good. Drag racing in particular is a sport where you cannot "have it all". Some things must be sacrificed in the name of performance.
Hard ride does not bother me, and I will talk to my mechanic about doing the shocks and replacing the bushings with urethane.
I cannot give up my car now, I am moving to another home in about 2 or 3 months, and is consuming all my time.
I will try to make a couple of passes if I can get to Donaldsonville or Hattiesburg track in next month or so. I will get DRs first, and have located two stock wheels real cheap with only cosmetic damage. I will get them soon as possible. Will notify every one what happens. I noticed another Z person test drove a new Z and had wheel hop as I did. I forgot who it was, but if you see his post, have him contact me or let him know the vdc must be shut off.
joerx
 

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joerx said:
Can only safely use 7lbs boost with stock pistons and connec. rods. Have seen others have connec. rods fail at 10lbs boost. I do not think I will change connecting rods and pistons-too much work, and too much down time to pull engine.

I still am asking if turbo car will show proper hp on dyno. I dont think since air does not pass thru intercooler. What do you think. Thunder racing in Baton Rouge charges $90.00 for two pulls. What do you think ?
joerx

Most places with dynos have high output fans they put in front of the car.
 
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