A RWD VIS Integra - "The Hidden Forrest"

[sk15kev]

I thought I would put this up to see if anyone was intersted in helping  develop this as a decent A class racer.  The VIS Integra is won very early in the career mode so most of you should have one in the garage.

I firmly believe that this car should be more than capable of being an extremely good A Class RWD runner.  The Forza rear wing allows df of up to 250lbs, this should result in a very grippy ride.

I quickly built one up a few weeks ago with the aim of running it as a GT400.  Put it on Sport 245/18" tyres, reduced weight to 2098, put in all the aero and built engine to 354hp with 224lbs of tq.  Stuck a tune on it and went for a run.  Felt really good, but time was really slow.  Had a tweak and sent it out again.

0to60 - 5.05 ; 0to100 - 9.65 ;TS - 164 ; 100to0 - 270.5 ; G60 - 1.08 ; G120 - 1.09

RAS - 56.316
SEBS - 73.250
TSUB - 56.839
QR - 186.405

Not good...  Had a play, had a play some more and still couldn't get it to go fast.

So scrapped it built a Race tyre version and it worked a bit better.  Stiffened just about everything and added more camber.

I have played with this so much now, I don't think I can see the forrest for all those damn trees in the way.
It currently has a little mid corner oversteer push in low to med corner.  It shouldn't for the amount of aero it has.  I know the diff could be reduced, but I think this would mask the problem that is still there.

Feel free to have a try and let me know if you can make any improvements.

[sk15kev]

Race Tyre Build & Tune

0to60 - 4.82 ; 0to100 - 10.23 ;TS - 154.7 ; 100to0 - 250.8 ; G60 - 1.15 ; G120 - 1.17
245/18" - 290hp/183tq/2081lbs

Race Michelen / 18" / 245 / OZ Gemini
RWD PT Upgrade - Sport Ignition & Fuel, Street Block
All Race Handling & Aero

Tires = 29/29
gears = FD4.57//  2.89/1.99/1.51/1.20/1/0.85
Camber = -1/-0.9
toe = 0/0.1
caster = 5.4
ARB = 27.41/19.88
Springs = 443.9/271.4
Ride = 3/3
Rebound = 9.1/7.7
Bump = 2.7/2.4
Aero = 100/240
brakes = 49/100
Diff R = 54/38

RAS - 55.664
SEBS - 73.926
TSUB - 56.661
QR - 186.251

An expected improvement at RAS and TSUB, and the obvious lack of power in affect at SEBS.

[fndrbndr]

Getting rid of rear toe might help with that oversteer.  It'll also help you wring out every last bit of top speed from your 290 hp.  Stiffening the front ARB a smidge might also help.  That's just a first guess, though.

[sk15kev]

Ammended as mentioned below

Sport Tyre Build & Tune

0to60 - 5.05 ; 0to100 - 9.4 ;TS - 163.8 ; 100to0 - 272.1 ; G60 - 1.08 ; G120 - 1.10
245/18" - 353hp/223tq/2098lbs

Sport BF Goodrich / 18" / 245 / Roja R2-5
RWD PT Upgrade - Sport Intake, Race Exhaust, Sport Ignition & Fuel, Sport Block
All Race Handling & Aero except street brakes

old settings in brackets, changed are in red.

Tires = 29/29
gears = FD4.87//  2.89/1.99/1.51/1.20/1/0.85
Camber = -1/-0.9
toe = 0/-0.2(0.1)
caster = 5.4
ARB = 27.81/19.48(27.41/19.88)
Springs = 446.8/273.2 (443.9/271.4)
Ride = 3/3
Rebound = 9.5/7.6 (9.1/7.7)
Bump = 3.4/2.4 (2.7/2.4)
Aero = 100/245 (240)
brakes = 49/100
Diff R = 45/35 (54/38)

RAS - 55.5 (55.878)
SEBS - 72.885 (73.088)
TSUB - 56.54 (56.628)
QR - 184.925 (185.594)

Didn't expect it to be same time on Tsukuba.  Still not fast, but better.

[sk15kev]

Getting rid of rear toe might help with that oversteer.  It'll also help you wring out every last bit of top speed from your 290 hp.  Stiffening the front ARB a smidge might also help.  That's just a first guess, though.

Lol you snuck in before I could finish the posts.  Yes, agree.  Rear toe sort of left over from initial changes to get car to accelerate out of the sweeper on RAS. Will try if I get a chance to be on in the next few days, although no too likely at the moment.

[BarbecuePete]

Maybe somewhere between the 2 builds would work best Kev?

Most of the GT400 cars are around 2500lbs (I think), maybe try keeping the Slicks but go back down to a Sports level WR so you can add in a bit more power...

One of my issues with the FWD to RWD swaps in Forza though is the lack of available Rear tyre width because of narrow rear arches on FWD cars, (I won't go into just how stupid that is when you think of all the chassis work needed to fit a RWD swap in the first place  ) Anyway... I think even with the 245 section tyres you have its going to be a struggle to keep the back from stepping out, I see you've got pretty high DF on the back already, as Fndr said maybe tweaking the roll bars a bit could help... though i'd probably start by softening the rear rather than stiffening the front.

[sk15kev]

thanks Pete and agree on the tyres.
Only one opion for wr and it only takes off 280ish.

[Spiny Anteater]

The toe issue stood out to me as well.  I usually use feuerdog's -0.2 rear toe as a starting point for my RWDs, and rarely change it.

I also agree with the comments about the tyres on engine swaps, but to me there's another problem too. When you do the engine swap, the weight distribution never changes (and you would expect some changes at least what with the extra driveline etc.) so you not only have skinny tyres on the back you also have very little weight pushing those tyres into the ground. Softer springs do help, but ultimately there's still only the same small amount of force pushing the tyres into the tarmac whether the springs compress at 200 lb/in or 400 lb/in.

[fndrbndr]

Yeah, Fit's PT Cruiser is probably about the best RWD swap car I've seen.  Fit's tunes are a little hit or miss for me, but we get comparable times out of most builds.  Take a look at his tune if you want some ideas.  Warning: he liked/likes more oversteer than some do.

[sk15kev]

Okay I think I have this pretty good now.  thanks for all your help.  The tune has been updated above and will show its quick rank on my other thread for comparisson.

Feel free to try and let me know how you get on.  I really like this car as it is very stable and grippy, but no slug either.

Probably won't change the tune much now unless anyone says anything.


I did quickly try Pete's suggestion of adding weight putting, on slicks and reducing the power a bit.  Initially it seems to be good on RAS but the drop in power is noticable.  If I do anything more with this car it will be down this route.