Improve Traction on 2018 GT Roush Phase II Supercharged - Ideas?

[hlfbkd420]

Its not a serialized Roush. Its a badgeless GT with dealer installed Phase II blower, intercooler, and numerous other suspension mods and exterior enhancements. It is going into the performance shop shortly for additional power and other mods. It will be putting down in excess of 750 rwhp after the work is done. Hell could be closer to 800 rwhp. Going to 2.8 inch pulley, custom tune, and long tube headers.

I do not get any wheel hop really. In traction control mode, the computer is pulling timing to avoid rear slip. When traction control off, it will break grip if you hit it hard. I want to mitigate this loss of traction and out as much of that power to the ground as possible.

So what are others doing to upgrade the rear suspension?

Are you planning to run E85? If not I wouldn't pulley down due to heat issues.

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[Cory S]

Wider tires aren't going to help you. Your car is setup for handling, not weight transfer. Going to an R compound drag radial will help a little (10-15% tops), but if the car is lowered and has a PP suspension, your 5-40mph hook up attempts will always kind of suck.

 

[AgSurfer]

Are you planning to run E85? If not I wouldn't pulley down due to heat issues.

Was advised against running E-85 since I don't drive my cars regularly and they sit in storage for 6 months of the year.

 

[AgSurfer]

Wider tires aren't going to help you. Your car is setup for handling, not weight transfer. Going to an R compound drag radial will help a little (10-15% tops), but if the car is lowered and has a PP suspension, your 5-40mph hook up attempts will always kind of suck.

So your car appears to have similar power levels to what mine should be putting down after the various mods are done. How have you mitigated the traction loss issue with almost 800 rwph? I currently run Nitto NT05Rs on the rear and they do stick, but as you pointed out, can get some slippage and computer pulling timing to maintain traction control in the lower gears when you hit the pedal hard. Thanks.

 

[AgSurfer]

Are you planning to run E85? If not I wouldn't pulley down due to heat issues.

The larger coolers on the Roush Phase II won't help with potential heat soak issues if one pulleys down from 3.0" (stock) to 2.8"?

 

[Cory S]

So your car appears to have similar power levels to what mine should be putting down after the various mods are done. How have you mitigated the traction loss issue with almost 800 rwph? I currently run Nitto NT05Rs on the rear and they do stick, but as you pointed out, can get some slippage and computer pulling timing to maintain traction control in the lower gears when you hit the pedal hard. Thanks.

Stock suspension completely and Mickey Thompson SS’s. Hooking good even on cold asphalt. Just hit a 3.23 0-60 yesterday. I’ll be hitting 2.99-3.05 once warmer weather hits.

 

[brucelinc]

I would worry less about heat and more about detonation with that smaller pulley. It already has 12 psi of boost. That is enough with 12:1 compression. You will need to retard the timing or use higher than 93 octane fuel if you pulley down.

 

[AgSurfer]

I would worry less about heat and more about detonation with that smaller pulley. It already has 12 psi of boost. That is enough with 12:1 compression. You will need to retard the timing or use higher than 93 octane fuel if you pulley down.

Interesting. Thanks for sharing. I made a note of this. The performance / race shop I am working with is very experienced and professional, but I will make a note to review this with them.

Among other mods being done, one other thing they are also doing is upgrading the stock oil pump and timing gear to higher grade / billet oil pump and timing sprocket.

 

[brucelinc]

Interesting. Thanks for sharing. I made a note of this. The performance / race shop I am working with is very experienced and professional, but I will make a note to review this with them.

Among other mods being done, one other thing they are also doing is upgrading the stock oil pump and timing gear to higher grade / billet oil pump and timing sprocket.

I like the Roush kit and have one on my 2018. However, I will be a bit surprised if you get the power upgrade you are expecting. The Roush has a small throttle body compared to most other kits. That is a limiting factor.

Also, by increasing boost with the smaller pulley, they will almost have to pull timing to keep it safe. The headers should help and the custom tune might pick up some. Of course, the general design of the Roush also means heat is more of a factor....and not in a good way.

The latest Roush calibration does pretty well at maintaining power despite the heat and taking advantage of 93 octane fuel. Not saying a professional dyno tune won't be better but I wouldn't expect miracles unless you go E85 or race fuel.

 

[AgSurfer]

Understood. I am not focused on a hard goal per se, but it would seem that rwhp would be in the range of 750-800 after (a) 2.8" pulley, (b) long-tube headers (usually good for 20-30 rwhp), and (c) custom tune. Certainly want to be appropriately safe with the tune on the stock engine internals.

 

[AgSurfer]

I like the Roush kit and have one on my 2018. However, I will be a bit surprised if you get the power upgrade you are expecting. The Roush has a small throttle body compared to most other kits. That is a limiting factor.

Also, by increasing boost with the smaller pulley, they will almost have to pull timing to keep it safe. The headers should help and the custom tune might pick up some. Of course, the general design of the Roush also means heat is more of a factor....and not in a good way.

The latest Roush calibration does pretty well at maintaining power despite the heat and taking advantage of 93 octane fuel. Not saying a professional dyno tune won't be better but I wouldn't expect miracles unless you go E85 or race fuel.

So how do I say you're were right in so many ways. See my recent post in Forced Induction. The car just got finished today. It made 676 rwhp on mustang dyno. Not disappointed by any means; however, the shop did not baseline dyno my car. They said they have dyno'ed many Roush supercharged S550 mustangs and the strong stock ones typically put our around 600 rwhp.

Tuner and I talked in detail about the add'l boost from the 2.8" pulley, concerns on detonation, etc. Along with the custom tuning done, tuner said that Ford actually has excellent knock sensors and the dual-fuel injection systems on the gen III coyote also reduce detonation risks.

Curious if you have any other thoughts. Thanks.

 

[m3incorp]

The design of the Roush Supercharger is the biggest limiting factor for attaining really high horsepower. But then, on the other hand, it is one of the most reliable kits out there and makes great power for what it is. You still have a very strong car on your hands. How does the drive difference feel to you?

So how do I say you're were right in so many ways. See my recent post in Forced Induction. The car just got finished today. It made 676 rwhp on mustang dyno. Not disappointed by any means; however, the shop did not baseline dyno my car. They said they have dyno'ed many Roush supercharged S550 mustangs and the strong stock ones typically put our around 600 rwhp.

Tuner and I talked in detail about the add'l boost from the 2.8" pulley, concerns on detonation, etc. Along with the custom tuning done, tuner said that Ford actually has excellent knock sensors and the dual-fuel injection systems on the gen III coyote also reduce detonation risks.

Curious if you have any other thoughts. Thanks.

 

[AgSurfer]

The design of the Roush Supercharger is the biggest limiting factor for attaining really high horsepower. But then, on the other hand, it is one of the most reliable kits out there and makes great power for what it is. You still have a very strong car on your hands. How does the drive difference feel to you?

Have not picked it up yet. They just finished it this afternoon and they were road testing. Scheduled to pick up Friday morning. First thing I plan to do is air down the rear Nitto NT05Rs to say 25 psi.

The DSS one-piece forged AL drive shaft was not installed; it's still on back order - after 8 weeks. They still don't have an ETA on delivery date. But the shop said the install is quick and easy - about 1.5 hours including the front safety bracket / loop.

Excited to get it back.

 

[AgSurfer]

The design of the Roush Supercharger is the biggest limiting factor for attaining really high horsepower. But then, on the other hand, it is one of the most reliable kits out there and makes great power for what it is. You still have a very strong car on your hands. How does the drive difference feel to you?

out of curiosity, how did your car perform on the dyno? Are you still running Roush factory tune or did you get custom tune done?

 

[m3incorp]

If I remember right, I'll have to pull out the dyno but I think mine was around 635. Don't quote me on that though. Now you are going to make me find it tomorrow Mine still has the Roush tune. The only thing I have changed is the throttle body. BTW, the Roush kit uses the GT350 throttle body.

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