"The Feather"

[sk15kev]

For those that are interested here is the build that I used on the A Class Maple Reverse Hot Hatch Challenge.  It was basically a B class car that I lumped extra power on and tweked slightly.  All my own original work, applying a basic principal tune and making only one round of adjustments.  It probably has a lot more in it, especially for those guys that know what they are doing with gearboxes.

If you race it, you will be last off the line, however all is not lost as you will be overtaking everyone around the outside of the sweeping corners with ease.

Honda 1.5 Civic Vti - A Class

ratings speed 5.1, Accel 5.3, Brakes 6.2, Handling 5.8
Hp - 314, Trq lbs - 217, weight - 1941.

Engine Upgrade - FWD K20A powetrain
Race Block & Fuel, Street Ignition, Sport Exhaust.
All race handling including weight.
Race Goodyear 225 width with 17" rims sitting on Enkei RP03's
Forza Front Bumper, Rear Wing, Rear Bumper & Street Side Skirts

tyres - 28/30
gears FD- 4.37; 2.89, 1.99, 1.51, 1.2, 1, 0.85
Camber -1/-0.7
toe 0.1/0.1
caster 5.1
ARB 4.82/31.30
Spring 222.3/210.7
Ride 4.8/4.8
Rebound 5.6/3.4
Bump 4/2.5
Aero 125/130
brakes 47/100
Diff F 10/0

Enjoy and let me know how you get on, if you can bear to run any more of Maple Valley.

[Spiny Anteater]

I've onyl just seen this so these comments are just from eyeballing the settings:

1) I assume that the ARB settings are a less extreme version of the popular 1/40 setting?
2) How did you end up with those rebound settings, or are they carry overs from the B Class car? Have you tried lowering the bump settings - say multiplying your figures by 0.6-0.7?
3) More a question really, but that diff setting seems very low. I know that I've found low diff settings to work on FWD cars too, so I was wondering if you noticed a major improvement over the more usual 25-40% settings?
4) Is the struggle off the line due to gearing or traction? If it's traction, you might be able to get it to transfer less weight backwards by stiffening the springs (which look very soft) by say 50%. If it makes the car evil to drive you can always go back to your settings.

[sk15kev]

I've onyl just seen this so these comments are just from eyeballing the settings:

1) I assume that the ARB settings are a less extreme version of the popular 1/40 setting?
2) How did you end up with those rebound settings, or are they carry overs from the B Class car? Have you tried lowering the bump settings - say multiplying your figures by 0.6-0.7?
3) More a question really, but that diff setting seems very low. I know that I've found low diff settings to work on FWD cars too, so I was wondering if you noticed a major improvement over the more usual 25-40% settings?
4) Is the struggle off the line due to gearing or traction? If it's traction, you might be able to get it to transfer less weight backwards by stiffening the springs (which look very soft) by say 50%. If it makes the car evil to drive you can always go back to your settings.

Spiny,

1) Guilty
2) Yes again and no haven't adjusted as it feels spot on.  It doesn't seem to flinch on any of the Maple kerbs.
3) Yes again, as I posted on your FSF thread I found it helps with sweeping turns on Maple.
4) Not traction, there is just not enough power in the little fella.  I could adjust 1st for more spark, but it was built meant for the hotlap challenge.
5) Give it a go, it doesn't cost much to build.

[fndrbndr]

A launch gear will definitely help off the line.  My solution (assuming the racing tranny, you generally like the ratios, and that you're not hitting sixth gear):

Look at your current ratio for 5th gear.  Make that the ratio for 6th.  Look at your ratio for 4th.  Make that 5th.  Repeat until firth gear is unnecessary.  Make first a launch gear.  I like to set it so that it maxes out about 30-40mph, but individual tastes vary, as do cars, so ymmv.

If you're not otherwise happy with the tranny, hit Fit's transmission ratios thread.  There's a lot of good stuff there.

[sk15kev]

My feelings are hurt that nobody has built and driven the car.

So Spiny & fndrbndr you have gifts to do with as you please.

[fndrbndr]

Thanks.  Between the spec miata project and the challenges (including school), my forza time's been a bit limited.  I'll let you know my impressions tonight.

[Spiny Anteater]

Thanks - I'm afraid that degenerated into the "round tuit" category, then I forgot when the new challenge came along . It doesn't help that I'm still on the hunt for where I packed away the writing materials, although at least Ikea have now furnished me with a pencil! I shall now proceed forthwith to see what I can get out of this and Hop's GT.

The rate this is going, I fear I may never complete the NSX runthough...

[sk15kev]

Sorry guys it wasn't a pressure tactic.   Please don't feel you have to.  They were gifts to take or leave as you please.

[Spiny Anteater]

It's Ok, I know it wasn't. I meant to get around to it, but as with everything else in life at the moment other stuff got in the way. Last night it was racing with Pete and some other guys which was good fun (I never turn down a good race!), but hopefully tonight I'll get it run - I want to see how it works out and it could well lead to a permanent upgrade for my Civic from C to A

[fndrbndr]

Spiny, I might be able to run this for a while.  I'm headed home, and could use a little decompression time between class/brainstorming and my work through the problem sets for tomorrow.  If you're on, I'll send you an invite.

[Spiny Anteater]

I'll be on in about half an hour - see you later.

[fndrbndr]

Spiny and I ran these around MVR.  It was consistent with my other cars from that challenge.  I found it a bit understeery, but generally good.  Tranny wasn't as much of an issue as I expected from your writeup, but I suspect that spiny's suggestion of stiffer rear springs would help, if not for the fact that it would make it more understeery.

[sk15kev]

Will give the rear springs a go.

[Spiny Anteater]

As fndr said, we ran these around MVS, although only for a few laps. My best lap was a 1:31.118, but I was pushing the car very hard to try to find the limits (and more!) and work out the characteristics of the car. I really believe that there is a second in there if I can give it a good run, which I will when I get chance...

First lap it felt very good - turn in wasn't up there with my Focus or Corrado, but it was very stable and I could still get on the power early. It was especially impressive through Turns 4, 3 and 2 (on bimmer's map) and I found I could be much more consistent through these corners than with my tunes. The problem was that once the tyres had warmed up the understeer Fndr mentioned became more noticeable. I noticed that your tyres are set a psi higher than mine, and I suspect that the tyres became "overpressured" - certainly I find that preformance goes away on all tyres once they get above 33psi. I think this problem would go away if you were to drop the tyres a psi.

Also, I'd be wary of raising the rear spring setting too much - the car is pretty nicely balanced on cold tyres so you don't want to go too far the other way. One other thing is that it doesn't like kerbs too much compared to my tunes - as it's softer sprung I suspect it may be grounding as the MV kerbs are quite high in places.

Finally, I built up the car to your spec in the first post but got a PI of 852. As I couldn't see what I missed (still can't!), I switched from Avons to Goodyears so that may have some impact on the performance of the car

[GBO Possum]

I could not get to A850 based on the recipe, so I did a few changes to get it within class A.

Here are the differences:-

Street Flywheel
Sport Driveline
Michelin slicks
Street Hood

The resulting weight is down 17 lbs to 1924

A touch slower than my personal best class A on MVReverse (01:30.127 with the Acura NSX 97) - best lap so far is 1:30.635

I've had a lot of fun with the car, so thanks!