Akina's build

[largeorangefont]

Well this escalated quickly. That weight is not too bad considering what you can still pull out.

[Supe]

Gives me hope that I can hit 2600 lbs, albeit with more/heavier cage.

[AKINA FC]

I believe that shouldnt be a problem Supe!  My tubing is 1.5" .120 wall so its heavy I also didnt realise that my car was  full tank at that weight either until i went to fill it up for testing on friday, only took a little over a gallon before starting to come up the filler neck and it holds a little over 15 gallons, I run it with about 6 gallons in it for time trials as it uses about 5 gallons in one run. So current race weight was 2648 on the scales, I think i can hit 2550 in race weight which will be nice!

We'll a little recap of the race weekend as it went ok but had its issues as expected. Arrived Friday afternoon for testing and made only one run due to the alternator deciding to crap out and charge at 18v towards the end of the first test session. Made some rounds in the pits looking for a spare alternator, found one luckily with a group of the CMC cars but the test sessions were over by the time I got it back together. I Really wanted to get back out as that first run the car was wicked loose, lot's of fun but not fast. I at least had a idea for tire pressures for setting grid in the morning.
First run saturday was a little better, still several seconds off where I used to be. I know some of the improvement from friday was just me getting used to the car again but at least now it wasn't trying to kill me haha. Oil temps were high, in the low 270* range which was a first for this car, coolant sat at about 207* which is normal. A second oil cooler is going to be needed for lower speed tracks like this and high ambient temps. The car is massively stiffer now and will not require near the spring rate I have now. It felt like a big go kart, skipping all over the place. Tires coulldn't do work at all, multiple spots on the track that the front end was coming off the ground, just highly unstable all around. Made some more pressure adustments, disconnected the rear bar, softened the shocks up as far as I could go and went out again.
Second run felt way better, not great by any means but better. Rear end was still pretty loose. Front end was better but still unstable on exit with any sort of surface irregularity, corner 7 would bounce the front off the ground under power (washboard) and send me to the grass in a hurry. Pulled in the hot pits after about 6 laps to check temps. Front camber was perfect as temps were within 5* across, rear needs less as the outsides were about 20* cooler. Really need to soften it up and let the tires work
Decided for run three to just go out to get more seat time and verify things. Team mate wanted to go out so I brought him with. Temps were up, car was the same, best lap was within a tenth of my last run. Came in and noticed the drive belt was shredding and lost a couple ribs, apparently the new/used alternator pulley was not in the same position as my old one and needed shimmed out some. It was hot and miserable so I just figured on skipping the last round and pulling the alternator to adjust it along with changing the ronin rear links to take the camber out after dinner when things cooled off some.
Started on the alternator after dinner, got it out and shimmed the pulley, went to install the battery cable and the stud just spins in the back of the alternator jacked around with it for a while realizing the part that the stud attaches with on the inside of the alternator is broken, put it back on hoping for some weird miracle and of course it wont charge. It's hot, I'm irritated, people are drunk....its time to head back to the hotel and try to figure something out in the morning.
Got back to the trailer early, tried taking things apart to see what i could do. the nearest new alternator is a good 45 mins one way, first round is at 9 and we planned on leaving shortly after lunch so I admitted defeat, packed up early, helped some friends, went for a ride with one and helped him find a littel over a second on his time and left. Exciting end right?
At least the learning level was high this weekend and I figured out what I needed to know to make the car work. I wish It would have been a little calmer and cooler so I would have been thinking about mounting the go pro and getting some vids. I can say the new racepak dash showed me a lot issues before they became bigger problems, I highly recommend something like that if you can afford it, it will save you money and time in the long run. Car is very fast and can't wait to get back out a little more prepared. I have a laundry list of little things to change and add 
Should have some photo's on the way to me in the mail as well.

[Supe]

I've got you beat - 1 3/4" .120 wall!


I'll be very interested to see where you settle on spring rates.  I always thought I was way on the light side, but after talking to an FC RX7 guru and multiple-time SCCA champion who engineers a lot of products for their ITS cars, he was adamant that even with aero my spring rates were bordering on too high, and that the cars performed best with lighter springs and stiffer speedway style sway bars.  I'm hoping he's right, because I really don't want to change springs.  I want to say I'm something around 525/375 or somewhere thereabouts, will have to check my old receipts. 

[frijolee]

With a round of changes as dramatic as you made, a "re-learning" curve has to be normal to get the setup dialed back in.  Stay the course amigo.  We're all rooting for you.

[largeorangefont]

I've got you beat - 1 3/4" .120 wall!


I'll be very interested to see where you settle on spring rates.  I always thought I was way on the light side, but after talking to an FC RX7 guru and multiple-time SCCA champion who engineers a lot of products for their ITS cars, he was adamant that even with aero my spring rates were bordering on too high, and that the cars performed best with lighter springs and stiffer speedway style sway bars.  I'm hoping he's right, because I really don't want to change springs.  I want to say I'm something around 525/375 or somewhere thereabouts, will have to check my old receipts. 

Yea.. I am sort of in the same boat with you. It is $1200 to take a swing at a new big speedway bar/softer suspension setup with no guarantee the car will be any better. I am sure those guys are smarter than me, but they are not running cars with our level of power either. The car is damn good as is, and I can actually reduce my front camber a bit with the setup I'm running now.

I'm at 700/400 now. I'm amazed Erik can run the rear spring rate he's been running. I was running 500 lb springs in the back and the car was a handful to drive and bounced badly over the bumps. I don't have too many complaints now, others than needing to revalve the rear shocks for the softer rates.

Erik,

Where are you reading oil temps from? I hit ~270 occasionally but I'm reading temps from the pan, so I sort of just ignore it I just change my oil after about 10 hours of track use. Oil reports have come back pretty healthy.

Did you redo the suspension at all? Or is it the same rates and setup you had before, just at a tighter/slower track? If you need to bounce (pun intended) any ideas around, feel free to drop me a line.

[AKINA FC]

With a round of changes as dramatic as you made, a "re-learning" curve has to be normal to get the setup dialed back in.  Stay the course amigo.  We're all rooting for you.

Thanks Joel and you are most correct, hard work and perserverence will prevail. 

I've got you beat - 1 3/4" .120 wall!


I'll be very interested to see where you settle on spring rates.  I always thought I was way on the light side, but after talking to an FC RX7 guru and multiple-time SCCA champion who engineers a lot of products for their ITS cars, he was adamant that even with aero my spring rates were bordering on too high, and that the cars performed best with lighter springs and stiffer speedway style sway bars.  I'm hoping he's right, because I really don't want to change springs.  I want to say I'm something around 525/375 or somewhere thereabouts, will have to check my old receipts.

That is heavy! haha you win that one.
I too have been noticing the light spring/heavy bar setup a lot with ep and its rx7's as I started doing research. I wish there was a few of them around here to do a little comparison. Your spring rates are half of what I am running and I would very curious as to see what its like with a few hundred pounds of down force, for reference i am at 900/800 and it felt awesome before the full chassis change. I believe it worked due to the chassis flex, extra weight and I believe the toyo's had softer sidewalls as well. Do you have a speedway style bar? Do you have any pictures of your setup? I'll show you mine if you show me yours 

I've got you beat - 1 3/4" .120 wall!


I'll be very interested to see where you settle on spring rates.  I always thought I was way on the light side, but after talking to an FC RX7 guru and multiple-time SCCA champion who engineers a lot of products for their ITS cars, he was adamant that even with aero my spring rates were bordering on too high, and that the cars performed best with lighter springs and stiffer speedway style sway bars.  I'm hoping he's right, because I really don't want to change springs.  I want to say I'm something around 525/375 or somewhere thereabouts, will have to check my old receipts. 

Yea.. I am sort of in the same boat with you. It is $1200 to take a swing at a new big speedway bar/softer suspension setup with no guarantee the car will be any better. I am sure those guys are smarter than me, but they are not running cars with our level of power either. The car is damn good as is, and I can actually reduce my front camber a bit with the setup I'm running now.

I'm at 700/400 now. I'm amazed Erik can run the rear spring rate he's been running. I was running 500 lb springs in the back and the car was a handful to drive and bounced badly over the bumps. I don't have too many complaints now, others than needing to revalve the rear shocks for the softer rates.

Erik,

Where are you reading oil temps from? I hit ~270 occasionally but I'm reading temps from the pan, so I sort of just ignore it I just change my oil after about 10 hours of track use. Oil reports have come back pretty healthy.

Did you redo the suspension at all? Or is it the same rates and setup you had before, just at a tighter/slower track? If you need to bounce (pun intended) any ideas around, feel free to drop me a line.

I have been really thinking about using a good set of bars and soft springs but just dont know how far to go or not to go with that setup. With stockish bars and the weight/power we have I think your rates are pretty close to what it needs to be, my thoughts were 800/500 for a initial change due to aero and larger tire. Using what I have now I think I'm just going to order 2 or 3 sets of springs and go to a test day one of my friends is doing as he is renting RPM during a weekend day for pretty cheap, only thoughts were the valving issue like you mentioned but I don't think it will be horrible, at least I hope not.
My oil temps are from the pan as well and I agree that as long as that isn't uber high its ok as the oil coming from the cooler is probably 20 or so degrees cooler entering the engine, just the first time its ever been that high but it was really hot out. Part of me says install a second cooler on the other side or put a bigger one on. The other half says just leave it alone as it was just a extreme setting and it didnt really do that bad.
Same suspension, didn't change a thing as I hoping it would have gone the other direction as I figured the grip level would go up the need for stiffer springs would increase, instead it went the opposite. I was at this track last year with the same setup and it was anywhere like this, its amazing how much the car changed.
I might do that Ash, send me a pm with your number again as Im not sure I saved it or not.

[largeorangefont]

Supe does not share pictures. I just have to scour these boards in random threads for random pictures of his car and piece it together in my mind. 

I think your chassis, the front specifically, is just too stiff for the suspension now.. Or stiff enough that the suspension actually works as intended . I would definitely throw some different springs on it as is. Even if the valving is off, you'll know immediately if you are going in the right direction.

I have my 12k/9K Fortune springs if you want to try them or just a pair of them.

I am sold on no rear sway bar, I don't think I will ever put one back on the car. My car was edgy loose with the 9K rear springs, even on smooth turns. It is more consistent now with the softer springs and other changes.

I need to do some more research on the front bar and really see what kind of data I can gather to decide if the speedway front bar is worth a try. I have thought of dropping to 650 # springs in front just to see what would happen.

I'll drop you a PM with my contact number.

[AKINA FC]

We'll after a lot of thought and some very well appreciated feedback from Charlie @ mazcare I have decided to go the softer spring/big bar route.  We're starting out at 450f/275r, 1-1/4" .250 wall speedway bar on front and my current tanabe bar in the rear, due to stagger I have. This by the numbers equates out to the same total spring load under cornering as what I am running currently as that bar with a 11" arm is about 450lbs at 5* of twist. So hopefully this retains the front end grip I have now underload, brings the rear grip WAAAAY up. Curious to hear some of your thoughts as well.

A couple shots from the weekend and weights before this race, fuel fuel, driver and gear.

[largeorangefont]

Oh boy, that is a huge swing. Is Charlie putting together the bar for you? Are you going up on rear bar or have you always run the Tenabe and just dropping the rear spring rate? I think your car is going to get much easier to drive.

PM me the details on the front bar. I'll do one as well if it can save us some money.

Car looks awesome. How much gas does it have in it for those weights?

[willcoop]

Your car is constantly getting better and better. I would also be interested in a front sway bar or more info on what your are planning on doing.

[cholmes]

I'm very interested in what you find with softer springs / bigger bar. I've always been surprised by the hugely stiff springs most people seem to run on these cars. Granted, mine's a street car, but it had 525 / 380 springs on it when I got it, and it just seemed to not hook up well around corners, especially if they were bumpy. I dropped to 340 / 250 and it made a big difference in grip both in the corner, and in getting the power down off the corner. All with stock front bar, no rear bar. Again, street tires, not race tires like you.

Next I'm going to try RB front bar, possibly along with a stock rear bar to keep balance. I may go even softer on springs with the bigger bar.

[largeorangefont]

Cholmes - Do the RB front and no rear bar. You'll really like it on the street I bet.

For tighter more technical tracks I can see going to a softer rear spring. I'm running 400lb rears now, I could see maybe 350, even 300. On the faster tracks I run the 400s seem pretty good, 350 might be a good all around compromise. I ran 500 lb springs before and it was too stiff over bumps, the car hopped around a lot.

I ran my car with RB front and rear bars when it was rotary powered and never really liked it. I felt like the rear bar did not put the power down as well, but cornered off power better.

Im really interested in this discussion and results.

[eage8]

+1

I'm really interested to see what the data says.  do you have decent data with the cars current setup on any tracks that you plan to compare back to back?

[cholmes]

Thanks for the tip on the RB bar largeorange, I'll try it like that.