Andrew & Tamra's 818SR EM Autox Hybrid Destroked Long-Rod Build

[AZPete]

When I built an FFR roadster I learned on the forum to trash the set screws. They are not needed to keep the height and they put dings on the sleeve threads that make turning the rings difficult.

[xxguitarist]

Long time follower, first time poster.

You two seem to be pretty o top of things so you may have tried this but didn't mention it. Have you tried to use a spring compressor to take the load off the collars when you adjust your shocks?I know those are smaller diameter than most OEM springs but you should be able to get one in there. There are several styles so it may take some trial and error. Probably can't use them while the shocks are on the car.

Keep up the great work! I love seeing your scientific method approach to just about everything on the car. Great ideas.

Joe

Joe,
Considered it. Increasingly considered it with that one corner. I really don't think our HF spring compressors would have done it with these small diameter springs. We needed it done now, not a few days later, or a few days after that, depending on which potential replacement set might have worked. We haven't tried, but I also try not to use those except where necessary.


Pete,
Interesting. No slipping down the road?
Seems like they should be inclined to vibrate out of position.

[Tamra]

Double header autocross this weekend! Heading to NNJR tomorrow and NER Sunday assuming the car holds together. We are slightly worried about tire rub with our lower ride heights. Pretty much the entire garage worth of tools is shoved into the van just in case.

[Canadian818]

Good luck!

[Tamra]

Fun day at NNJR! Bug didn't break AND managed 8th overall raw (let's not talk about pax lol). Lots of setup work left... The front doesn't work in sweepers and the rear doesn't work in transitions but we've got straight line acceleration down pat! Developing this car is going to be really fun.


Video:

[Frank818]

What a beautiful day!!

[Bob_n_Cincy]

Tamra,
I loved at the end of you video when you pated the steering wheel. (good pony, good pony)

Keep pounding on the car to find any issues. We will do the same.
Bob

[Tamra]

Thanks guys. I'll have a full report after the weekend. Andrew is racing the car again today at NER.. May make a few tweaks this morning if we have time (no time last night due to a family dinner). I'll be in the CSP Miata today.

[Tamra]

Successful 2nd day with Bug!

Andrew drove solo today. In the morning he concentrated on learning the handling and putting down a good time. The afternoon he started pushing the car to find its limits and test reliability. He started actually launching the car as well - might as well figure out how weak the axles are now to start strengthening everything. Nothing broke today and the data logs were excellent. He found the 2nd rev limiter (fuel cut) past the timing pull, which comes in at close to 7500 rpm and 71MPH in 2nd gear. He hit it every run in a fast slalom, but the car stuck it pretty well.

Here's a fun video of Andrew launching the car with two step, set at 4k, which spun the tires up easily (although it was only 60 out today and he was single driving, so they weren't hot at every start). To help reduce the drivetrain shock, he would pull the e-brake and preload the drive train by slipping the clutch slightly (takes out the backlash), and then put the e-brake down before launching.




Also, we are having some problems with our springs settling lower and lower. Despite starting at equal ride heights, after running a counter clockwise course yesterday, the passenger front corner is now a full 1/4" lower than the driver front, creating some mild rub issues. Also, our total ride height shrunk nearly an additional 1/2" after racing this weekend. Our car is shrinking! Is anyone else having this problem? We are considering switching springs at all four corners and going with Hypercoils. If we had paid to have our car corner balanced, we would be out $500 due to the springs. This is getting frustrating! Plus, when we tried to raise the ride height this morning, we found the collars frozen again despite only having the tiniest bit of pre-load. We'll have to put them in the vise again. Time to get new sleeves and try two collars rather than the set screw.

[Tamra]

Here's a video of Andrew driving the course. As you can see, the car is still a bit of a handful and requires fast hands in some places. This should improve more with additional set up work. The hard limiter section (bep bep bep) was 71 MPH in 2nd gear at just under 7500rpm. We were surprised he made it there, since we have timing pulled starting at 6900 rpm, and the power drop off is very noticeable.

[R.Spec]

Here's a video of Andrew driving the course. As you can see, the car is still a bit of a handful and requires fast hands in some places. This should improve more with additional set up work. The hard limiter section (bep bep bep) was 71 MPH in 2nd gear at just under 7500rpm. We were surprised he made it there, since we have timing pulled starting at 6900 rpm, and the power drop off is very noticeable.

Cannot wait to get my 818 done!

[idf]

Successful 2nd day with Bug!

Andrew drove solo today. In the morning he concentrated on learning the handling and putting down a good time. The afternoon he started pushing the car to find its limits and test reliability. He started actually launching the car as well - might as well figure out how weak the axles are now to start strengthening everything. Nothing broke today and the data logs were excellent. He found the 2nd rev limiter (fuel cut) past the timing pull, which comes in at close to 7500 rpm and 71MPH in 2nd gear. He hit it every run in a fast slalom, but the car stuck it pretty well.

Here's a fun video of Andrew launching the car with two step, set at 4k, which spun the tires up easily (although it was only 60 out today and he was single driving, so they weren't hot at every start). To help reduce the drivetrain shock, he would pull the e-brake and preload the drive train by slipping the clutch slightly (takes out the backlash), and then put the e-brake down before launching.




Also, we are having some problems with our springs settling lower and lower. Despite starting at equal ride heights, after running a counter clockwise course yesterday, the passenger front corner is now a full 1/4" lower than the driver front, creating some mild rub issues. Also, our total ride height shrunk nearly an additional 1/2" after racing this weekend. Our car is shrinking! Is anyone else having this problem? We are considering switching springs at all four corners and going with Hypercoils. If we had paid to have our car corner balanced, we would be out $500 due to the springs. This is getting frustrating! Plus, when we tried to raise the ride height this morning, we found the collars frozen again despite only having the tiniest bit of pre-load. We'll have to put them in the vise again. Time to get new sleeves and try two collars rather than the set screw.

Is there enough bind in your suspension or grip between the tires and floor that the car does not fully settle until you have driven it? If you have not, try rolling and bouncing the car before measuring the ride height.

[xxguitarist]

Is there enough bind in your suspension or grip between the tires and floor that the car does not fully settle until you have driven it? If you have not, try rolling and bouncing the car before measuring the ride height.

We always roll the car back & forth a few feet before measuring ride height. The suspension doesn't bind much at all.

In this case, the car was autocrossed Sat & Sunday, jacking it up to put different front tires on for trailering each time, and even Sunday it got shorter between the morning & end of day.

[metalmaker12]

You gotta drive the car with two people to load each spring correctly is what I found out.

[Scargo]

Those are no-name springs, aren't they? The ones that came with mine are. I've been satisfied with my Eibach and H&S springs.

Metalmaker: You don't compete in autocross with two people in the car so that's not how you would want to set it up or corner-balance it. I think racing in Auto-X is their main focus for the car.

[Tamra]

They are no name springs as far as we can tell.

Good springs don't settle. I think we will be ordering some Hypercoils tonight.

In our post in the suspension forum someone said that they measured the FFR springs once and had a 70lb difference in rate in two 350 lb springs!! That's not good at all.

[Tamra]

Springs are ordered. This coming weekend we will be testing Hypercoils on all 4 corners, sticking with the same 500lb fronts (although by the sounds of it, who knows what the real rate was of the no-name springs), and going from 300lb rears to 450lbs. We are using all of the shock travel and hitting the bump stops in the rear, causing handling issues in transitions.

In the front, we are using about 2" of travel, of 3.5" available.


You can see the dirt line more clearly in this photo, indicating max travel used:


Passenger side tire rub (low side due to poor quality springs):


Also, upon post race inspection, we noticed that our upper ball joint boots are getting torn badly. The other side of this one is also torn. Is anyone else experiencing this? Any solutions?

[Kurk818]

I found my boots torn before i even had the wheels installed. I packed a bit more grease in them and left them as is for now. Interested to see what others have done.

[metalmaker12]

Those are no-name springs, aren't they? The ones that came with mine are. I've been satisfied with my Eibach and H&S springs.

Metalmaker: You don't compete in autocross with two people in the car so that's not how you would want to set it up or corner-balance it. I think racing in Auto-X is their main focus for the car.

True, I was just stating what I did and it seemed to work.

Also , guys what's your ride height. I am right at 4.5 now, it only takes a single cruise/ shakedown to settle the springs, I have had the same issue with many good name coilovers. They all seem to settle a bit. Maybe you just had them set to low and it just took some runs to work them down. The car is lite so rolling it around doesn't settle the springs, you have to drive it, stop and go, turn hard etc.

[Erik W. Treves]

Silly question. ...been over a year...but I seem to recall the rates were supposed to be installed with 500's in the back? 350's up front with sway bar.....again been a bit....if you are not running a bar then obviously the 500's up front make sense....but the 300's are not for rear with R shocks...I did the same thing on mine ... things got much better with the 500's in the back!

[Tamra]

True, I was just stating what I did and it seemed to work.

Also , guys what's your ride height. I am right at 4.5 now, it only takes a single cruise/ shakedown to settle the springs, I have had the same issue with many good name coilovers. They all seem to settle a bit. Maybe you just had them set to low and it just took some runs to work them down. The car is lite so rolling it around doesn't settle the springs, you have to drive it, stop and go, turn hard etc.

Taking the measuring tape out of the picture, we autocrossed the car on Saturday. At the end of the day, we rolled the passenger tire up on a board, which allowed us to get the jack under the car. On Sunday, the car was autocrossed again. At the end of the day, same process, we rolled the passenger tire up on a board. However, this time, we could no longer get a jack under the car. Both times were on a flat surface. The car continued shrinking well beyond many hard stops and turns.

Silly question. ...been over a year...but I seem to recall the rates were supposed to be installed with 500's in the back? 350's up front with sway bar.....again been a bit....if you are not running a bar then obviously the 500's up front make sense....but the 300's are not for rear with R shocks...I did the same thing on mine ... things got much better with the 500's in the back!

Yep, the 500's are up front, no sway bar yet. The FFR recommended setup is for track use which is not usually in line with autocross setup. We have a long road of spring experiments ahead of us. This weekend it will be 500f/450R.

[Wayne Presley]

I'd order 400 front and put the 500's in the rear

[tmoretta]

Does that recomm. go for a mostly street car (occasional track car) set up also?

[Hindsight]

If one were to buy better quality springs for street/HPDE use (no autoX), what rates would be suggested front and rear, and would those rates still work with the FFR provided yellow shocks?

[Erik W. Treves]

I autox mine with front splitter and rear spoiler and had 500's in the rear and 350's up front...I tried the other way around and it was a mess...at least for me....

[Wayne Presley]

Does that recomm. go for a mostly street car (occasional track car) set up also?

No, for street I'd do 350 front and 500 rear.

[Hindsight]

No, for street I'd do 350 front and 500 rear.

Thanks Wayne - would those rates still work with the yellow FFR shocks that come on the S?

[Tamra]

Thanks Wayne - would those rates still work with the yellow FFR shocks that come on the S?

Per my understanding, the Koni Yellows are great for street spring rates (unless the ones designed for the 818 are different for some reason). As you go up in spring rate, you want to adjust the damping to match the spring rate, but since the yellows are only adjustable for rebound, then the bump damping becomes very poor. You could contact Koni to get them revalved for stiffer springs. Their price is very reasonable.

Wayne, we already ordered the 450/500 combo, but we may try switching which end the heavier spring is on at some point. In my experience, 50lbs can make a significant difference in handling.

[Hindsight]

Thanks Tamra, that was exactly my concern. I've upgraded springs on another car many years back, without upgrading the shocks and had poor results. I didn't know if the rates Wayne suggested were far enough off from the FFR springs to require different shocks but sounds like it would.

[Tamra]

Koni is usually quick to respond. I would recommend you email them and ask.

[Hindsight]

Thanks for the tip! I will give it a shot.

[RetroRacing]

If I remember correctly, Yellows are only good to 500Lbs, after that, they overheat quite quickly.

[PleiadsMan]

awesome guys keep it up! That thing must be a monster

[Frank818]

500 rear for street? Aren't we with... 275 from FFR?

[Wayne Presley]

Tamara's car will have some aero downforce at autocross speed but most of the grip will be mechanical. For autocross, the higher spring rates will help with body roll and allow the car to transition right to left faster. Suspension frequency is a better indicator of actual rate than the actual springs.

[D Clary]

I agree with Wayne, the left to right transitions require stiffer spring to reduce the recovery time of the chassis changing directions. You will probably end up much stiffer than you thought you would. That has been my autox experience, the better it is for autox the worst it is on the street.

[Scargo]

... Suspension frequency is a better indicator of actual rate than the actual springs.

I've heard this before but how do you do real world measuring and evaluating of this? I have seen really sophisticated McLaren stuff but it seemed out of reach, price-wise. I'm dreaming I can find a way to rent sensors if there is such a thing and if it seems worthwhile. As it is, I'm just doing the amateurish, old guy thing. How good does it need to be or what am I leaving on the table, that I can even feel? That's where I'm at with the STi. I have gas, double-action racing shocks and 600/800 pound springs on a 3000 pound car and I only have my buttfeelerometer to go by and I am halfway lost with how to make adjustments. I'm not going to make wholesale changes just because I'm going to a smoother/rougher course. I need an average roadcourse setup.
I used to do SCCA Solo and autocross and those parking lots sure can vary in smoothness, cleanliness and grip.

[D Clary]

I think your butt is really all you have, that and a stopwatch. Stiffen the springs and play with the shocks. In reality you need double adjusting shocks to adjust compression and rebound. Road course and auto x are very different. the transitions come at a much slower pace and the car has plenty of time to recover, so it can be a little softer. I'm just an old guy too so it doesn't take as much to stroke my ego and get an adrenaline rush. On the other hand winning is very nice.

[xxguitarist]

I've heard this before but how do you do real world measuring and evaluating of this? I have seen really sophisticated McLaren stuff but it seemed out of reach, price-wise. I'm dreaming I can find a way to rent sensors if there is such a thing and if it seems worthwhile.

For under $2k, you can get a race-tech DL1 sport with 8 analog inputs, and 4x linear potentiometers, then record data fast enough to see the shocks oscillate after a single (square-edged-ish) bump.

You'd be on your own to machine/fabricate something to attach the shock pots to the top & bottom of the coilover.

[Frank818]

Ok I get it, the 500 rears are for autoXing, but not for say a DD that never autoXes. Then yeah Wayne's explanation makes a lot of sense. I thought the 500 were for a street car not racing.