I finally got a chance to put up a blog entry on the last three days of testing we did last weekend. Our Evo IX is now ready to run at Targa!

Final Test Days at Thunderhill and Sears Point

The big changes we made between this test and the prior test were to the suspension. The car is now running a 26mm front bar to match the 24mm rear bar, and spring rates front to rear are very close to each other (500lb. front, 550lb. rear). That front bar really transformed the handing of the car.

Only one month before the car gets on the transporter, and two months before the start of the event!

 

Sounds like you guys have her dialed in. Hope they have this one on speed, Targas are second only to rally racing on my list.

 

Targa is broadcast some time before the holidays on primetime TV in Canada, and typically is broadcast on SPEED channel in March. Every year someone records the broadcast in Canada and makes it available online. I'll be sure to post about it.

I'll be blogging about the event every day, regardless, including posting in-car video and photos. I'm talking to a leading broadcaster about posting it to their web site as well, so you'll be able to track our progress during the event.

 

I don't think those stiffer springs and bar are helping up front. You may have decreased body roll in the front but you took grip away doing so. Larger bars make the wheels less active and lower traction, it's not conjecture.

Are you planning on drifting the car through the corners at the targa or driving a racing line? That will make a big difference on how you set-up the car. Have you done any gravel rallies? Tarmac is not easy, I have raced SCCA club rally in Group 2 cars and learning to rally in the gravel where the traction is consistently low is easier than jumping straight into tarmac.

You will have a good time no matter what, just take it easy there's no need to smash up your car on it's first race.

 

What do you mean by "less active?"

A bigger bar in front is certainly not the popular setup, but I haven't heard anybody except for Peter try it out and report on the effect on handling.

 

Sorry, but you're wrong. I was fighting with significant understeer, and increasing the front bar and spring rate reduced understeer. If what you said was true, I would have increased understeer.

You are correct in that you can make the car too stiff and reduce overall grip, but I think with this bar size and spring rate I am still nowhere near the limits on this chassis.

Think about this one for a second. The car comes stock with, what, 200lb springs? What do you do to improve the handling of the car? You increase spring rate everywhere. By your logic, you're decreasing traction. Yet why then are you able to turn faster lap times and hold higher cornering G's with that set-up over stock? That would imply vastly _improved_ traction.

Making a car handle comes down to managing weight transfer effectively to let each contact patch work at it's limit. With the weight of my car and the amount of body roll that it used to have, the outside front wheel was being asked to support too much weight and was both overheating and overloading that tire. That decreased front end grip.

Increasing the front anti-roll bar on the car is transferring some of the load back to the inside front wheel and is letting the front end work better to pull the car through the corner. I know this worked for two reasons -- significantly decreased tire temps, better balance between the front tire temps, and less pressure increase in the front tires from the heat. That's just the data, and excludes driver feel and lap time.

I have not raced on gravel, but I did the Team O'Neil school. There are some things which are similar between the two surfaces, but car set-up is radically different.

Targa demands a car that changes direction well. You obviously try your best to drive a proper racing line, but many times you simply do not know where the road is going to go and have to be able to both slow down and then react quickly once you see where the road goes. The worst case scenario is a car with terminal understeer, as just like a gravel event there is no run-off.

I have road raced for 4 years, and autocrossed for about 5 years before that. I've done Targa Newfoundland 3 times, including having co-driven the overall winning car in 2003. I helped build two competitive cars for the event, and learned from both of those builds what works and what does not work for the conditions.

Agreed. It's a lot easier to wreck than to win at Targa. That said, my goal is to run up front so the risk will be there. There's a fine balance between leaving a little bit on the table and being uncompetitive.

 

BTW, trying a bigger front bar didn't come out of nowhere. I did a fair bit of research and talked to a few suspension gurus about this. It turns out that Ralliart specifies a 27mm-25mm front anti-roll bar matched to a 23-24mm rear bar for tarmac rally events.

 

looking good... Im very impressed cant wait to see some results!!!

 

Finally....someone agrees with me on the front bar!

Yes...it does make a positve difference in certain cases. Definitely NOT the way to go on gravel due decreased wheel independence. BUT minimizing dynamic camber loss up front is the key, and if done right, it can make a mean set-up for tarmac.

Good luck!


- Andrew

 

You're selling Whiteline parts, so you're not alone. Lots of crazy Ozzies also agree with us!

 

I agree, I'm just too lazy to put mine on.

Thanks for putting up these updates on the progress of the car, I really enjoy them. Good luck with the event.

jeff

 

Forget lazy -- you need to basically drop the entire front subframe to put the bar in. Yikes!

 

I'm sure adding the front bar improved the cars performance in your case, but your thought process on how it actually improved the performance is flawed. GTWORX has the right idea, and with your soft spring rates the front outside tire camber is certainly the problem. If your car was set up with the correct amount of camber(probably not possible with spring rates as soft as you're running) increasing front roll stiffness would shift the balance towards understeer due to increased load on the front tires. Obviously in your case, better camber control produced more grip then the increased tire load took away. If your car has as much negative camber in the front as possible then you're probably on the right track with your setup.

good luck

 

I agree with the above and couldn't spit that out last night like I wanted. I meant to ask how much camber you were running in the front, it didn't seem like a ton by the pictures but it's hard to tell. Also what is your toe setting in the rear?

That's cool you've got experience in the event as a co-driver you should do fine. I didn't read enough of your other posts to know if you had any sort of seat time with rallies. Tarmac is really cool, it's too bad they don't really do it in the States. I totally know what you mean about being able to make changes quickly in turns - that's why I wondered if you were going to drive a static racing line or drift. If you commit to the drifting line/setup it's easier to make adjustments mid-corner. But it's much harder on tires and typically has a steeper initial learning curve on Tarmac. What type of cars did you co-drive for?

 

Ride height is set to at or slightly above stock, and so the camber is set to maximum. I would agree that more camber is needed, and limiting camber loss is certainly part of where the improvement is coming from. I'm probably doing a poor job of making my case for load transfer, and will have to break out my Carroll Smith books to reiterate my thought.