GT-R NISMO GT3 Base Model '13 drag problems

  • Thread starter Denezin
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Denezin
Hi, I have a GT-R NISMO GT3 Base Model '13 that ive tried over and over to tune for the 1/4th. Problem is when i launch it wheel hops where the rear of the car is jumping up and down no matter how i tune the trans or add ballast or no ballast. Ive posted before and its always been a silly little thing ive missed her or there. Can someone give me some insight? Thanks for your time =)
 
What do you mean by jumping up and down?
If its squatting and then rebounding as you launch then it is probably a combination of the springs being too soft and inadequate damping, the ride height might be too low as well.

When we accelerate weight is transferred away from the front wheels and on to the rear, if the springs/dampers are too soft and the ride height is too low then you will bottom out the springs.

From what I've seen of drag tuning the common pattern seems to be running the lowest rear spring rate and the highest ride height in order to generate the maximum amount of rear wheel grip under acceleration. The GT3 cars might not have adequate ride height in order to run this style so the first place to look would be rear damper compression, increasing this will slow the compression speed and might be able to slow it down just enough to stop it bottoming out as the acceleration forces balance (increased front damper extension will help as well but not as much). Increasing rear damper extension and front damper compression will help maintain rear wheel traction during gear shifts by preventing it transferring eight forwards as acceleration forces diminish.
If increased damping doesn't solve it then you need to increase the rear spring rate until it does 👍
 
DolHaus i thank you once again for shedding insight. My suspension tune is as follows

Ride Height :Highest :Highest

with the stiffest settings on all others (F spring rate is 39.72 and R is 15.80 both are maxxed) with no toe or chamber.

When i say jump its like the wheels are bouncing off the pavement trying to catch traction but only for split seconds at a time, Very strange. Thanks again for looking =)
 
DolHaus i thank you once again for shedding insight. My suspension tune is as follows

Ride Height :Highest :Highest

with the stiffest settings on all others (F spring rate is 39.72 and R is 15.80 both are maxxed) with no toe or chamber.

When i say jump its like the wheels are bouncing off the pavement trying to catch traction but only for split seconds at a time, Very strange. Thanks again for looking =)
Ok, so in that case you are going to want to soften everything up, knock the dampers back to 3 all round and then drop the spring rates considerably, you should see a great increase in launch grip. The suspension has no give in it and is recoiling (bouncing) in response to the backwards weight shift during acceleration 👍

Stiff springs aren't going to help in drag racing, the point of stiff springs on a circuit racing car is to retain stability during direction change and increase response speed to input from the driver, the downside of this is that they generate less physical traction due to reduced weight transfer. In drag racing the main concern is grip, stability is far less critical so soft springs are the way to go as they will generate more traction.
 
A very strange thing has occurred. After switching back to the stock suspension the wheel hopping stopped. So i put the custom back on and raised the ride height and bingo! back to wheel hopping it went. set to 100 and now it does not do it anymore. It was set to max at 130 and now at 100 has no problem at all in launching. Thanks for the help! Will post more updates if found.
 
Something else to consider is dropping front ride height to near min to give even more grip as the car will level out under acceleration as this is a GTR keeping traction in the front is just as important as the rear so you can keep the 50:50 split for max traction.
As @DolHaus stated increased front dampers will help with weight transfer during shifts I'd dare say near max on both compression and extension with springs at 3/4 max on the front.
Rear go the exact opposite direction. Near min on springs and dampers with maxed ride hight
 
Something else to consider is dropping front ride height to near min to give even more grip as the car will level out under acceleration as this is a GTR keeping traction in the front is just as important as the rear so you can keep the 50:50 split for max traction.
As @DolHaus stated increased front dampers will help with weight transfer during shifts I'd dare say near max on both compression and extension with springs at 3/4 max on the front.
Rear go the exact opposite direction. Near min on springs and dampers with maxed ride hight

It's a GTR but not a 4WD one.
 
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