New member 1st thread; Suspension mod stages?

[Seraphim38]

Hello all,

This is my first thread here and I hope not to get flamed for my first thread. I am hoping to learn about what can be done next in modifying my suspension particularly to attain more grip in the rear end. I have tried to digest the roll center threads here and elsewhere but can’t seem to come up with a list of logical stages to perform modifications in.

I have my first autocross event this weekend and am very excited. I have extensive motorcycle road racing experience and karting but no big car action yet. I do believe that the best modification one can make is to get more track time and mentoring, which is a given. Assuming that is the case…

I have an 89 240sx S13 hatchback with the following:
Nismo power brace
Tanabe super 7 Pro coilovers (springs rates unknown, damping set at medium front, Soft rear)
Megan tie rods, traction rods, RUCAs, tension rods etc.
Energy suspension poly bushings throughout
ST (?) larger front sway bar front and possibly rear
Strut tower braces front and rear
Enkei RPF1 17x9/10 staggered with 235/255 Azenis
Kaaz 1.5 lsd
Interior is stripped in the back
Spec’d alignment that is in the ballpark of the standard specs listed here.

The car's balance is good; it has only a hint of oversteer and plenty if you get on the gas mid corner. During the last couple autox events the car was at (with its previous owner), the instructors kept fighting over who would get to drive the car next and they said it was their favorite car there.

The SR20DET / GT2871R combination puts down more power than the chassis can handle; it can break the rear end loose too easily in my opinion even with 255s in the back. The back end will spin up easily in 2nd when the power band hits in a straight line w/ dry pavement. With a little bit of damp ground this morning it spun up in 3rd on the freeway in a straight line when I wasn't even trying to. Although this might make me grin, power that I can’t make stick is really wasted. I am guessing that the Azenis don’t like cold weather daily driving so I am planning on going up to 255 fr /275 rear Nitto NT05s but am curious on what the next logical steps would be to improve rear end traction. I plan on relocating the battery to the back (Odyssey 925 or Optima 51R) and having at least a 4 point roll bar setup in the back because the chassis flexes a lot. I am mentally prepared to ditch all the Megan stuff and pickup Parts Shop Max parts but I don’t think I really need it yet. I have heard that it might help to remove the rear swaybar, but I am not thinking that the traction is that much worse in a hard corner compared to straight line acceleration.

Thanks for any wisdom that can be imparted, and I am hoping that people don’t suggest to start over with my suspension. Should I add aftermarket RLCAs? Modified joints? Rear knuckles? Subframe spacers? Softer springs in the rear? Thoughts?

[e1_griego]

Drive a few events as a baseline and go from there before you add more parts.

The only reason I say ditch the jdmtyt3 tanabes is because I've spent the last 2 years on Stance bull****. Sure it's fun, but the konis feel sooooo much better.

I dont' think a jump to 275s is worth it, but that's just me. You argued with me on NWN about rear grip from 255s -- mine have been never bothered me, even with the big turbo and all that. Star specs have held the power, and the rs3s seem to hold up as well.

[McCoy]

I'd say start by getting rid of the azenis... the NT05's have a good track record by a few members here for holding their ground with 2871R's on track and on the street.

[Seraphim38]

e1_griego: of course I must express gratitude and respect for you--I wouldn't even know of this forum if you hadn't suggested it to me. I may be willing to purchase the Koni coilover setup after I have done a few events and know the limits of the car as is. Of course I also have a few of the other modifications in the works but Konis can certainly be put on the lower part of the list.

McCoy: I really do believe that the Azenis are a big part of the problem for my car. I do suspect that a different set of shoes are likely to make a huge difference. It's too bad that nobody stocks the Nt05s up here.

[McCoy]

I've driven on Azenis... I know it's your problem, or most of it.

I live in an even more remote location... that's what tires.com and tirerack.com are for ;).

[e1_griego]

I'm not saying run out and buy konis, but if you're serious about autocross then you'll want to upgrade from jdmtytess soon.

[Sleepy_Steve]

Step up to 255's in the front as well?

I was about to ask what you have for brakes but then I read autox. Good HPS / HP+ or similar pad should do fine on stock brakes for autox. At least as long as you're running street tires.


Edit, I hate my azenies... Even if they are way better than my all seasons.

[PDM075]

Hello all,


I have my first autocross event this weekend and am very excited.


ST (?) larger front sway bar front and possibly rear

Enkei RPF1 17x9/10 staggered with 235/255 Azenis
Kaaz 1.5 lsd
Interior is stripped in the back
Spec’d alignment that is in the ballpark of the standard specs listed here.



.........welcome to the forums, and welcome to Street Mod. (the money pit of door slammer auto-x cars. If you come to larger NW events, you will likely see me and Logr. (I mainly run at Packwood, but may run in Shelton or Bremerton for testing reasons.)

Azeni's are old....meaning in age and technology and are not current for a streetable auto-x tire. Burn them up and move up to newer, stickier technology.

Don't bother with a rear bar for now...stick to stock to keep power down better with proper rear alignment.






The SR20DET / GT2871R combination puts down more power than the chassis can handle; it can break the rear end loose too easily in my opinion even with 255s in the back. The back end will spin up easily in 2nd when the power band hits in a straight line w/ dry pavement. With a little bit of damp ground this morning it spun up in 3rd on the freeway in a straight line when I wasn't even trying to. Although this might make me grin, power that I can’t make stick is really wasted. I am guessing that the Azenis don’t like cold weather daily driving so I am planning on going up to 255 fr /275 rear Nitto NT05s but am curious on what the next logical steps would be to improve rear end traction. I plan on relocating the battery to the back (Odyssey 925 or Optima 51R) and having at least a 4 point roll bar setup in the back because the chassis flexes a lot. I am mentally prepared to ditch all the Megan stuff and pickup Parts Shop Max parts but I don’t think I really need it yet. I have heard that it might help to remove the rear swaybar, but I am not thinking that the traction is that much worse in a hard corner compared to straight line acceleration.



Don't worry about chassis flex if you're serious about auto-x. Extra weight vs improvement is moot. I've never run a cage or roll bar in any of my 240 auto-x race cars, and don't even run strut bars (to save weight) With road race/track cars chassis stiffness comes into play MUCH more than auto-x, since we are NEVER in any given corner for more than a few seconds, and the majority of our movement is thrashing back and forth side to side in a frequency the opposite of road racing.

Moving weight around is also not the biggest issue. It's more ensuring suspension is allowing rear end to hook up - meaning proper dampening of proper shocks, proper rear end alignment, and ensuring you are not running on the rear bump stops.

S13 roll centers are flawed - thus why S13's make great drift cars.


and BEFORE, you start spending a butt load of money - get seat time. In the PNW, there are some active senior drivers that have been racing for 20+ more years than I have and this is my 29th season. Drive as many events as possible, take as many of the driver's schools offered, and then graduate up to the Evolution schools if you are serious.


don

[Def]

A bigger rear bar is needed on these cars, but running no bar is just trying to mask the ridiculous amounts of anti-squat the S13 rear subframe has. S14 subframe is so much better in that respect.

Most crappy coilovers have no droop travel in the rear, so that's another issue.

I recommend 255/40-17 all around. I've had RT-615 and NT-05s, the NT-05s have WAY more grip, especially when up to temp. Mine would always hold in 2nd in a straight line getting on it. Now with RA-1s that are up to temp the car really doesn't feel like it has too much power even in lower gears. But 2nd is generally too short to ever use on a track (hint for the conepackers - 2nd gear is for cruising around the Wal Mart parking lot... oh wait, that is what you're doing!!! :p :D).

I suggest just going to a few DEs and seeing what you want to change on the car. I imagine it'll be drastically different than what you think needs to be changed now. Oh, and turn the boost way down your first few events.

[e1_griego]

I am still loathe to put 255s on front.

I had the tire guy mount a 255 on my front wheel last weekend (before putting on the extra pair of 235s I had) and I'm not sure how to get it to fit without some heavyish fender work.

I think I would have to raise the car (and prob throw a 7" spring in), just to start. Or maybe the car doesn't roll as much as I think and I just need to nut up and buy them lol

http://img.photobucket.com/albums/v168/e1griego/0a22202d.jpg

Sorry, didn't mean to thread hijack.

[Def]

Just need to sac up - they fit fine with a little bit of work. :D

http://img88.imageshack.us/img88/8339/msr21911horseshoe.jpg

[e1_griego]

My fenders are so nice though :(

We'll see. :)

[Tower240sx]

realistically how much better is Parts by max than Megan???

seems like a fairly lateral progression to me

[Seraphim38]

Wow, I am very thankful for everyone's responses. A couple of answers to questions;

I have z32 brakes on all corners with HPS pads. Fenders are stock but rolled and pulled. I am confident that I can fit 275s in the back but the 255s up front might rub even with the small H&R spacer that's on the car now. I plan on going widebody or installing flares as needed.

I have read that going to 255s in front might slow down steering response and if I do need that much tire up front, I can have a fluid cooler installed for the power steering as well.

I am sure that there is going to be a lot of experienced autoX guys in the PNW that I can learn from. This weekend's event is sold out but I am the only 240sx there, so there's nobody to ask questions about specifically on the 240sx platform. Across the street from my office is one of the best NW 240sx builders for drifting, but I don't think he has built many grip cars...(super good mechanic though).

Anyway, thanks again everyond for your help. In the next week or so I will get the race head with 264 cams, Ti valve hardware, larger top feed injector setup, new tune and other goodies installed to finish off the motor mods. I will order NT05s as soon as I can, and then continue the mod habit...

[e1_griego]

Across the street from my office is one of the best NW 240sx builders for drifting, but I don't think he has built many grip cars...(super good mechanic though).
.

Who's that?

[Seraphim38]

Ray - Garage AutoHero. Super good mechanic...my car loves him.

[logr]

If you are serious about autox, check the rules. You probably want SM but a "power brace" is not legal there. You can take out the back seat but not the rest. XP would be your next choice where those things are legal. SM is tough but XP is tougher.

Smooth power is best.

Autox is great because it is a real race, with real competition and something most of us can, sort of, afford.

I tried most forms of racing and track days before settling on autox 5 years ago. I thought I was a fairly good driver until I tried autox. It kicked my ass and still is. My car is way better than I am but it helps make up for me. Handling before power is best.
Moral; practice, practice, practice, learn, learn, learn.

[e1_griego]

Ray - Garage AutoHero. Super good mechanic...my car loves him.

Ah ok.

Ray knows what's up for sure.

[Seraphim38]

I do not know much of anything about the class structure but I do anticipate that my car in its current configuration is not legal in SM since the interior is stripped and there are probably several other modifications that would put me out of SM.

Part of my experience in other racing platforms reinforces the need for having realistic performance expectations based on your budget. I have a friend that I used to race with who is competing in SCCA and I don't have anywhere near the wealth that he pours into the hobby.

For me it's about going out and having a good time. If I go out and have a good time and am priviledged enough to be competitive, that's a bonus. I know that I will not be willing to devote the amount of money or time required to be the #1 plate holder in any particular class. I do however intend on going out and pushing both my car and myself. Racing is in my blood; I tend to go crazy if I am not out racing something.

[PDM075]

Fenders are stock but rolled and pulled. I am confident that I can fit 275s in the back but the 255s up front might rub even with the small H&R spacer that's on the car now. I plan on going widebody or installing flares as needed.


Anyway, thanks again everyond for your help. In the next week or so I will get the race head with 264 cams, Ti valve hardware, larger top feed injector setup, new tune and other goodies installed to finish off the motor mods. I will order NT05s as soon as I can, and then continue the mod habit...


With flares and bodywork, guys have fit 315's up front in SM trim. I used to run 305's out back and easily could fit 315's - but with proper wheel inward fitment.


264 Cams are a complete waste of time if you plan to auto-x seriously. They are way too laggy and peaky. As Logr mentions smoothness is the key to a fast car, so torque and smooth power delivery is important. My street/track car Fatboy runs 264's, and even with cam timing and tuning - it lags way too much for auto-x and sucks trying to come out of corners.

[Seraphim38]

After my first autocross day, here are the results:

Conditions were pouring torrential rain with standing water all over the track. Per suggestions here I turned the boost controller down to the internal wastegate spring setting of 7psi but it wasn’t enough to prevent the car from being ridiculously difficult to drive fast in the rain.

I went out with an instructor in my car and ran a few sessions, continuing to shave time until I got to the point where I was only gaining a half a second or second with each lap. It was terribly difficult to keep the rearend from drifting out, even though in the dry the cornering doesn’t exhibit oversteer. I found after the first 4 runs that my best friend did 6 seconds better than me in his Infiniti G37S with street tires and coilovers/suspension mods. I kept telling the instructors that I was working really hard to be smooth on the wheel and the throttle even though the back wanted to come out under any level of throttle. By the end of the day I was driving the car through most of the course with either the backend sliding slightly but not drifting wide, or the front end pushing.

After instructional sessions concluded I coaxed 3 instructors to drive my car, (all top annual finishers in SCCA solo events). Amongst 3 instructors there were 8 total spinouts, and we’re talking 270s and 360s not just drifting sideways. The first instructor said it was the most absurd power delivery for any vehicle he had ever driven because the rear end would come out super easy once it let go it wouldn't come back. They suggested that the Azenis were horrible on the car and I get some serious meat on the back.

Going into this event I felt that the car had very poor grip due to the Azenis but didn’t want to make excuses for my inability to drive it. In the end, even after repeated attempts, none of the instructors could match the time I got in my car. Thus I felt a little vindicated and learned a lot about my car in the process.

Every car on the track was running Star Specs, but they don’t make them in 275/40/17, so I think that my choice will be NT05s for daily driving. I will get them mounted and then have the alignment re-checked. I will check the rear spring rates and consider decreasing them.

Results:
Power delivery; plenty
Suspension; very little body roll, went over pavement transitions well, very little front-end drive under braking
Brakes; z32 brakes were fair but not enough rear braking as the fronts locked a little too easily. Might need an aftermarket proportional valve and/ or a rear brake upgrade. In the dry it might need better brakes all around
Tires; horrid, tragic fail

[n00b240sx]

You may want to try to search the forums, ebay and craigslist for a good deal on some wheels/tires you can dedicate for track use only. I hit up an autox a couple of weeks ago, on some really crap tires, ended up 2 seconds slower than than the next closest guy runnin star specs.

[Seraphim38]

Update:

I had 275/40/17 Nitto NT05s mounted up yesterday in place of the rear 255 Azenis RT615. First impressions noted that the NT05s are only slightly wider and a little taller, and grip only slightly more. The Azenis showed more wear on the inside of the tire than the outside, either from excessive squat or an alignment with way too much negative camber (if I understand correctly, though I definitely could be wrong).

Thus, it appears that my alignment could significantly be reducing grip. I have an appointment Tuesday morning with the best shop nearby that can align to specs, and I am eager to see how much more grip I can get with a proper alignment.

[Seraphim38]

dirty car...and the tires seem to look wider in person than in the photos. Probably due to my Blackberry's camera lens being less than stellar.

http://i113.photobucket.com/albums/n233/seraphim38/240sx/Edmonds-20110324-00291.jpg

http://i113.photobucket.com/albums/n233/seraphim38/240sx/EastSeattle-20110325-00293.jpg

http://i113.photobucket.com/albums/n233/seraphim38/240sx/EastSeattle-20110325-00292.jpg

I still can't help but wonder if some Battle Version or PBM components wouldn't help (replacements for the Megan tie rods, traction rods, toe rods and RUCAs isntalled by the previous owner).

[Def]

The rod ends are probably worn out on all that cheap stuff, but you can just replace that and be fine. I do suggest ditching the tie rods.

If you haven't aligned your car, it can definitely make the car drive horribly, so I'd start there. It's step 1 before adding more parts to the car. Go for around:

Frt Rear
-2.5 -1.3 to -1.5 deg camber
0 1/8-3/16" total toe in

Adjust the traction rod to 8.5" or whatever the length is Epstein recommended in his bumpsteer thread. I'm pretty sure it's 8.5".

Honestly, some of what you are feeling might be due to the aggressive clutch diff and non-digressive shock valving on your coilovers. It just makes the car extremely difficult to drive, and not very consistent. Unfortunately listening to advice from people who primarily drift sometimes ends up making your car slower and harder to drive if you're not sliding sideways. Just a different way to setup a car to do a different style of driving.

Unfortunately in my experience the NT-05s and RT-615's both suck in anything over mildly wet conditions. The NT-05s have way more overall grip in the dry though (both putting down the power and in a corner). They seemed to wear better as well.

Get an alignment though and see how it is.

[e1_griego]

Are you going to be at Golden Gardens on Sunday?

[Seraphim38]

Will be at Golden Gardens on Sunday afternoon to visit but sincerely doubt I will take my car there. Once I had a vehicle stolen right after a show, I don't ever talk my vehicles to shows anymore.

PM me if you are going to have your car there...well, if you want to introduce yourself PM me your contact info anyway and I can at least introduce myself.

[e1_griego]

It's not a show... just a giant meet full of idiots. 600+ cars usually, at least from the last few years. I'll def have my car there. Looks like a stock car with rpf1s. And relatively 4x4 lol.

I'm leaving by 1 or 2 I'm guessing. I'll be there pretty damned early. Five zero 3, nine 3 one, 3148 is my number.

[Tom Moore]

I've driven on Azenis... I know it's your problem, or most of it.

I drifted on RT615's & they greased instantly....& i have a stock(ish) KA. ;)

[Seraphim38]

So, it turned out the alignment had something to do with it. Camber was -2.7 in front and -2.6 in back. They lowered the back to -1.5 and front to -1.6 (I requested between 1.5 to 2.0 and they went to the low end of the scale). The rear was toed out and is now toe in at .08". The car feels like it has about 20% more traction in the back and tracks better. It feels more neutral overall.

The installation of the 275/40/17 NT05s provided as much of an improvement as the alignment did, so overall I can now hook 2nd gear in a straight line if I boost 13psi at 100 gain or boost higher and turn the gain down on the Blitz ibc.

I now have to swap the 235/40/17 front Azenis for 255/40/17 NT05s to match. Rear wheels are 17x9.5 +38 RPF1s, and I think I need to either bump up to 17x10 +18 all the way around as my fronts have a small H&R spacer to enable clearance over the coilovers.

The alignment shop said that all the fittings and settings on the Megan crap was tight, so I can delay the swap of SPL parts until it gets more necessary for some other reason. I do want to change out my squeaky poly bushings in the rear for solid collars though.