Would at least 200 horsepower help with understeer problems in autocross?

[rm3000]

Hi Im currently trying to build a naturally aspirated LX for autocross, I know the car is going to have understeer but would increasing the power to a least 200 or above fix some of this problem?

[buzz11]

Upgraded suspension parts should help with understeer. Larger rear sway bar is what I would go with

[deevergote]

More power won't really help with understeer. You'll just understeer faster!

Understeer has to be addressed via your suspension. Rather than regurgitate this info, I'll just share this convenient image from Speed Academy.

[wagon-r]

Agree. In a FWD car, the front wheels are being asked to both turn and accelerate. If you increase the acceleration, there will be less traction available to turn. So, if you actually used that higher hp during a turn, it would increase your understeer, not decrease it. And if you don't use the higher hp, it doesn't matter.

A good LSD can help you accelerate out of turns, although it doesn't help until you get the speed scrubbed off enough to make the turn.

But, as already said, suspension work is really the only way to decrease understeer.

[rm3000]

Thanks to all of you guys for the advice and great information very helpful, I had a question about what kind of suspension kits I should look at any Ideas?

[sonikaccord]

I'm going to add that weight distribution as well as total weight can affect how much understeer you have. More weight over the front axle will increase understeer.

Suspension: Is this a strict race car only vehicle? Daily? Double duty?

[deevergote]

Another thing to do is shed weight. Especially in front of the axles. You want some weight on the front (or else traction will be an issue), but there's a lot of removable weight there. Ditch your air conditioning. All of it. Much of it is in front of the engine, with a few things inside the cabin. Dump it all, and you'll save a great deal of weight. Dump your power steering, if you think you can drive well enough without it (be sure to modify your rack properly.) Get a high quality "half radiator". Get a lightweight battery, and/or relocate it to the trunk. These things will help make your car less nose-heavy, and they'll lighten it overall. Less weight is sometimes better than more power.

Thanks to all of you guys for the advice and great information very helpful, I had a question about what kind of suspension kits I should look at any Ideas?

What do you mean by "suspension kit"? There are numerous parts that can increase your car's performance. In most cases, you're not going to find them in a "kit"... not without paying a fortune, or buying some cheap knockoff junk.

What is your level of experience in autocross? Have you ever done it before? If not, I suggest not modifying your car at all. Get some decent performance summer tires, replace your brake pads with something one step up from a standard street pad (replace rotors if necessary), and replace all of your car's fluids. Then go race. You'll be painfully slow. However, any modifications you will do will simply be crutches. You need to get your skill level up to the point that the only thing holding you back is your car. THEN upgrade.

Additionally, make sure any mods you do won't put you in a different class. Simple modifications like a carbon fiber hood can change your rating enough to plop you into a class in which you'll have no chance of being competitive. Don't do anything that is going to put you out of your depth, or it'll only be frustrating.

Finally, I know this is going beyond the scope of the thread a bit, but how much research have you done for this build? Are you aware how extensive a naturally aspirated 200hp F22A build is? Or how expensive? 200hp is attainable, sure. It's even streetable, to some extent. But still... you'll be spending 3x your car's worth, or more, on your engine alone.

[af_1132]

My boy, rm3000! That's my student! He came auto crossing with me on Saturday, rode passenger, and now he's hooked too.

I have to say, from experience, that our cars have issues with mid-corner understeer more than on entry or exit with suspension modified and weight reduced. I've reduced a ton of weight in the back, not as much in the front, and the understeer is now showing up at the limit in auto x corners.

Like Deev said, start off with the car as stock (good condition tires and breaks) to get a base and to get used to the car's capabilities and weak points.

Once you are ready to upgrade, I want to suggest the following:
1. Fortune 500 series coilovers combined with Swift Springs (I have 12k spring rates for the fronts and 8k spring rates for the rears).
2. ST Suspensions front sway bar (the company sells then as a set, and it comes with a MUCH thicker front sway bar). I would sell the rear bar if you can't buy them individually and buy a Progress rear bar, which will aid in reducing the corner exit understeer. The Progress bar is GOLD.
3. Energy Suspension polyurethane bushing kit. No doubt, when you make your final choice on a CB7 purchase, you will have to replace worn out bushings.
4. New lower ball joints from Honda and SPC camber adjustable upper ball joints front and rear.

Some of these upgrades repair the wear and tear that the 20+ year car has endured, but also improve the handling, making them a win-win.

That's a pretty decent amount of money spent. Then we should talk about alignment adjustments, traction bars, strut bars, brake upgrades, and high quality tires as well. I hope tishock chimes in.

[deevergote]

Wouldn't hurt to have the suspension professionally set up once all that stuff is installed, if you can find a good shop to do it.

[af_1132]

Wouldn't hurt to have the suspension professionally set up once all that stuff is installed, if you can find a good shop to do it.

Certainly, without a proper alignment followed by a corner balancing service, most of these items will not be set up correctly. We have a few good alignment shops, one that I trust more than the others that I will recommend to you (rm3000).

The auto x events we attend are comprised of a single open class for all entrants, so luckily, rm can run what he brung without the worry of being bumped into a higher level where he will be out of his league.

[islandhopper]

+1 for the Progress rear sway bar. DRAMATICALLY reduced understeer in my 90 DX, if not negated it in most situations..even in the wet. I retained the stock front sway bar which, from personal experience and what most people have said, seems to be a great combo if you're getting a lot understeer.

[deevergote]

That's good. The first event I ever attended was at Honda Day (2006, maybe?) here in NJ. After going through tech inspection, my car was ALMOST stuck in with S2000s and ITRs! If I had a CF hood, I'd have been bumped up a class (which is why I used that as an example.)
I ended up not competing anyway (never actually have autocrossed yet... this year will be the year.)

That being said, my Miata was actually professionally set up for autocross. Corner balanced with the previous owner in the car. Unfortunately, I outweigh him by 60lbs or more, so that doesn't really help me much! He did the Miata equivalent to the suspension setup you described above. Engine was bone stock, aside from an intake and advanced ignition timing (10hp gain, supposedly.) The previous owner hung with an S2000 and an Elise at his last event. A car that has half the horsepower of an S2000, and a similar curb weight to an Elise (also with a power deficit), and he held his own. Didn't beat them, but wasn't a shameful 3rd. That's what a properly set up suspension will get you... along with the skill to use it effectively.
I cannot stress enough the importance of mastering your car as it is before upgrading it, though. You'll grow much faster as a driver if your car grows along with you. If you dive in with a modified car (as I'm going to be with my Miata), your personal progress will actually be slower... and you'll perform well under what the car is capable of.

[deevergote]

I just started reading the free ebook on farnorthracing.com. Might be worth a look.

[rm3000]

Thank you (af_1132) and (deevergote) for all of your help and information, I am even more inspired then before to focus on getting my LX and get going on the simple things you recommended like tires, brakes and fluids. Cant wait until I can start racing. Thanks Again

[masospaghetti]

I have no problems getting my car to rotate. The key, I think, is the thicker rear sway bar. I use the ST Suspensions bar which is nice because it's a bolt on, although it doesn't fit very well with the aftermarket exhaust that I bought. (It fit with the stock exhaust just fine.)

I have the stock EX sway bar in the front, poly sway bar bushings front and back.