Do you mind if I ask which "rotary guru" suggested that style of lapping? Need to lap my housings, I've heard of using valve grinding compound, I just want to do it right the first time.

Car is super sweet btw!

 

Surprised you are getting rear lockup like that. I tend to smoke the fronts sometimes but rarely the rears. Back to stock pads on the back?

On the fuel level: You probably aren't going to want to go much lower than 3/4 tank or so. These cars tend to have real bad starvation issues in long or fast left handers.

Otherwise, the car looks amazing and seems like its pretty quick. Great job! I really need to get down to DC to see it. Are you going to run the Pro?

 

You dont even feel the tire coming off the ground and landing again.

In a Macpherson front strut suspension, the inside front tire is hardly even loaded in a hard cornering situation. Lifting the inside front means you are hooked up, and probably close to being dialed in. Any Macpherson strut race car does the same thing.

Generally these strut coilover setups have very little droop travel. This is by design. It keeps you from having to run a stiffer sway bar, and keeps weight transfer to the outside wheels to a minimum

 

Thanks! I am surprised how "nice" it has turned out. But people at the event were definitely poking fun at me - all my cars previous to this have been bought mint and kept mint. So this is definitely a departure.

It's not lapping - it's "prepping." Lapping implies you're removing metal to get the surface flat. Not the goal here. The goal here is to rough up the surface and knock the shine off so it will hold oil well. The guy's name is Lynn Hanover, and he's over on the nopistons.com forum. Lots of the porting gurus hang out over there since it's high SNR in the engine build area.

Hm. I think part of it may be my fault actually, because I was trying to get the ride height up. I may have actually pre-loaded the front springs which means they're definitely not going to droop any when the car is set down. I need to re-check the front spring perches and see if there is a load on them with the car off the ground.

Either way, having a small amount of droop seems desirable to me. I can't imagine it's good for the dampers to have NO droop.

 

Well that could be. You appear to have a little bit of droop from your pictures, but it is hard to tell how much when comparing your static picture to your action picture. I would agree you do need a little droop to settle the car over small undulations.

I have around an inch or slightly more of droop travel all around in my car (I have it in my notes but I have forgotten). I remember earlier in the thread you were a little worried about the overall length of the front struts. Are you able to space the strut down at all at the CC plate? That is how I adjust droop on my Mustang with Bilsteins and coilovers.

 

I have about 1 inch of drop on my car as well. (JIC FLT-TAR coilovers)

I'm not sure how much of this is due to the strut and how much is due to the sway bar holding it up.. I don't remember if it drops more when I have both sides of the car up.

 

You know it's bad when an untuned, NA RX-7 is powersliding through a sweeper. :ack:

 

Update:

Cars handle a lot better when their front control arms and anti-roll bar aren't completely bound up due to too-tight bushings.

 

Did you add spacers or shave down the bushings? I've done this on my swaybars front & rear and my car's handling became much more predictable at the limit.

 

I had to fab up some spacers for the control arms and used washers for the front bar. The car has some bite up front now (finally) so hopefully it'll be a bit more competitive as a result.

 

First event since freeing up the front end was the NE Divisional championships, held this weekend at FedEx Field. My co-driver and I swung down on Friday to do some practice runs. It immediately became apparent that although the front end was working really well, the rear end was not happy. Way too much rotation mid corner and no compliance on the very bumpy lot.

We went for the quick fix for Saturday's runs, and softened the rear bar to the softer of the two holes (I run the stock rear bar with a couple extra holes drilled). We also softened the rear shocks almost all the way and dropped the rear tire pressure. While the car was manageable on Saturday, and we posted raw times within .25 of the leader, both of us were having trouble keeping the rear end behind us. Especially over bumps.

For Sunday I decided we had better throw on the softer rear springs I bought. We went from 350lb-in rear springs to 275s. Forgetting to bring the right allen key for the spring perches meant I wasn't able to raise the rear ride height back up to compensate, so we had additional camber and toe as well as a more rearward roll center. The car was a bunch better, but we fought a steady state and on-throttle push for Sunday's runs. Even so, my co-driver ran a 52.8, not too far off the 52.5 of the class leader. I had a 52.8 with a cone (story of my weekend) but both of us felt we could have gone faster if the rear end would rotate more.

I plan to take out some rear camber and possibly some toe. I had been running 2.5 degrees negative camber in the rear and 1/4" total toe-in. I'm thinking that moving to 1/8" total toe-in in the rear and 2 degrees negative camber will get us back in the ballpark. If it's still tight, I can raise the rear end up slightly (there is no rake in the car right now) and / or stiffen the rear bar back up.

We're definitely in fine-tuning mode for the suspension now - just need to get the car on the dyno and see if we can find a bit more power, drop some more weight, and learn to drive the thing.

 

Alignment was definitely hosed. Dropping the rear added camber and apparently I never added more front camber after I lowered the front either. I broke out the camber gauge (aka a long 2x4, fishing line, plumb bob and a ruler) and measured the car. -2.4 on each side in the front and -2.75 on each side in the rear.

I put the front back at -3.5 and am going to try the rear at -2. Front toe is 1/8" total out and rear toe is 1/8" total in. Stiffened the rear bar to it's stiffer setting and we'll try this again. If it's still too tight maybe I'll split the difference on rear spring rate and do a 300 lb-in set back there.

Progress....

 

Damn, you guys would have had a real shot at Ian if you stayed off the cones. Nice runs for an underdeveloped (for now) car!

 

Unfortunately STS was pretty slow overall for this event - Ian was way off his normal pace. Not sure why - we were running 1st heat so that was part of it, but still not particularly encouraging. But the car still isn't really working "right" so I'll withhold judgement until I'm happy with how it's handling and how I'm driving. If it's slow then - well, who knows.

I think this is only our fourth event in the car. So for that little development - not terrible.

Couple videos from Sunday are here:

http://vimeo.com/user3952339

 

Your exhaust sounds great!

 

Hey, just a tip for all the kids out there. When you're hastily throwing your engine together, don't rush so much that you put the 6-port sleeves in 180 degrees off. Because as it turns out, that makes a pretty big difference in the power level of the car.



Fortunately, you can flip them back the right way without removing the LIM / UIM.

Enjoying the newfound power,

JV

 

Well, at least you caught it. **** happens.

How do you switch them without removing the LIM? Just curious, seems physically impossible .

 

Pull the actuators/rods off, rotate sleeves, put actuators/rods back in, ensuring that the rods engage the sleeves properly, else you're back where you started. That is, unless he's using telekinesis. Be interesting to see what this sucker is putting to the wheels. Best of luck, fellow cone-chaser.

 

Given how familiar you are with NAs I suspect you'd think of this too, but:

If you remove the bolt and small phillips screw that hold the shafts to the outside of the LIM, you will notice that there is a pac-man shaped retaining ring that prevents them from pulling out during operation. If you unbolt the screw and bolt, you can slide the shaft out.

Once that's unbolted you can rotate the shaft 180 degrees. Now the sleeve is phased correctly but the shaft where it meets the aux actuator is not. Solution: Pull the shafts out as far as you can so they disengage from the pin on the sleeves, rotate the shaft 180 (the sleeve remains where it is) and push them back in to re-engage.

John

 

that's a good trick!

 

Interesting thread, thanks for the information. I've been running my '90 GTU for the past 2 years in ES and look forward to moving on to STS next year. Stock my car has lots of rake due to the rear end sitting up in the air. What ride height are you at now, from ground to top of fender opening?

 

I don't have my setup sheet here but if I remember right, last time I checked the front was 12 3/4" from the center of the wheel to the fender top and the rear was 13" using the same measurement.

Car has been doing well. We have made quite a few changes to the suspension trying to find that sweet spot of being neutral but also predictable and friendly. My latest setup is 450lb/in front springs with a big ST front bar, 275 lb/in rears with no bar. Front camber -3.5 and 1/8" total toe-out, rear camber -2.0 with 1/8" total toe-in.

My co-driver and I finished 2-3 at the DC ProSolo but pretty far back from our main competition. I picked up a set of 15" Hankook RS-3s and a set of wheels to try and we'll see if we like them at the Toledo Pro in a couple weeks.

The car is super fun and we're getting closer for sure.

 

i see a camera!!

VIDS NAO!!@!

 

http://vimeo.com/user3952339

 

looking awesome John, your car is probably faster than mine haha.