Drivetrain mods needed for 650+ whp

[Wicked95AWD]

I just finished upgrading my turbo to a Super (60mm inducer) HX40 with a 7 blade billet (HTA) wheel. This is a 69 lb per min turbo and should be capable of nearly 700whp. It should also spool very nicely with my extra displacement. I have performed all the necessary engine and fuel modifications (see profile for details) to support the hp levels this turbo setup is capable of, however, I need expert opinions about drivetrain upgrades. The only drivetrain related mods I currently have are: Energy motor mount inserts, a Shep stage 1 rebuilt transmission, a Fidanza lightweight flywheel, and an SBR4000hd clutch kit. My diffs, axles, and driveshaft are all stock. My plan is to baby the car and drive it at the new hp level until something breaks because I don't have the money to upgrade my drivetrain parts right now. I have already decided on a PTT twin disc clutch kit, and a cryo treated Shep stage 4 tranny with a 4 spider diff and Raxles race axles. Will I need to upgrade any other drivetrain components to prevent excessive downtime from broken parts?

 

[19BLACKGST98]

Do you have a link for the Raxles race axles you are looking at?

 

[daren_p]

I don't think Raxles has any info posted on their HD axles (well actually they don't really have any specific info posted). Last time I checked they were around $440 for the fronts (only offer them for the fronts & awds only) with a good core, other wise theres an additional $160 core charge. I don't know the specifics on what components they use (probably something like stock inners/outers with a 300M bar) but they do have a lifetime warranty. Tim Z. (twicks) uses them in his 700+awhp Eclipse & hasn't broken one yet, so they should work for most members on here

I don't know the sepcifics of what exactly will need to be replaced but at those kinds of power levels, it won't be uncommon to break lots of things (just ask the guys making that kind of power ). For the rear axles, you'll probably atleast want to look at the DSS bar upgrades, which upgrades the factory weak link. I think the rear ends are fairly reliable at those power levels but sometimes guys take out the transfercases. You could have a spare just incase or DSS also makes & upgraded output shaft. Shep also offers an upgraded T case.

 

[twicks69]

Instead of going the extra spendy route of an upgraded transfer case and rear axles, I would reccomend having a well-tuned coilover setup with a fairly good spring rate on the rear. When I was running 500# front springs, and 330# rear springs unloaded, the car bucked around like I was at the rodeo. After preloading the rear springs up a bit, I ended up happy with around 700# (1 1/8" of preload on the 330# spring, which equates to 18 threads as the thread pitch is 16 threads per inch). I also purchased a set of 550# springs if I feel like getting a bit more out of it in the future. If you are going to preload your coilover springs, I strongly suggest purchasing a set of coilover thrust bearings so you can easily preload your springs while on the car, making life a heck of alot easier while reducing coil bind during preload. Your coilover adjustment threads, locks and spanner wrenches (along with those little hands around sharp things) will like you alot more!

Here is a link to the thrust bearings:
COILOVER THRUST BEARING KIT

You will need two sets for the entire vehicle. They install at the base of the spring, allowing you to easily spin the locks while adjusting.


Always be sure to have your springs tested prior to installation because you cannot trust what the vendor says is your actual spring rate. Trust me; I have seen so many different combinations of spring rates in advertisements for the exact same model coilover it is stupid. If you have a circle track racing place around the area, or some other type of professional motorsports shop near you, they would likely have a spring tester in-house.


If you want to get a new set of springs with any spring rate you want, check out Afco or HyperCoil springs:

AFCO

Welcome to Hyperco Their catalog link is: http://www.hypercoils.com/PDF/page_12.pdf

Hypercoils sells rates off the shelf ranging from 175# to 1300#, and list price around $75-80 each spring.

If I remember correctly (I cannot remember off the top of my head if it is a 7" or an 8"-long spring), you will want 2.5" x 8" springs: Here is the link directly to the page:
AFCO: 8 Inch

Afco's springs rates range from 200#-650#, and list price around $66 each spring.


A well dialed in suspension will save parts. As well, I would strongly suggest good slicks, and learning how to preload your drivetrain using the E-brake and the twin-disk setup, so you leave the line without shocking your drivetrain components and causing breakage.

There is no need to spend $1800+ on the rear axles alone, and then another $2500 on an upgraded transfer case. Spend it on coilovers instead, and for less than $1000, you can retain your stock transfer case, rear axles and rear end if properly setup.

For good off-the-shelf coilovers, check out KW Variant 3 and JIC FLT-A2 (A.K.A. FLT-AR); these are pro level coilovers in the $1,700-$2,500 range. The more budget friendly K-Sport Kontrol Pro, Tein Type Flex, and D2 Pro coilovers ranging from $700-$1,100.

I have had no problems with my K-Sport Kontrol Pro coilovers over the years, but I am just one person.

As well, be sure you have the capability of adjusting camber and caster for the front and at least camber for the rear. All the basic "washer" rear camber kits are just fine, and either go with adjustable upper camber plates for the front, or adjustable upper control arms to adjust these very important suspension variables.

Check out Specialty products for their billet aluminum upper front control arms with adjustable ball joints for the 2G as an option if you don't want to do camber plates.

Both the control arms and camber adjustment parts can be found here: RRE's Eclipse Camber Correction, Camber Plate and Bearing Plate Info





Good luck!

 

[twicks69]

Do you have a link for the Raxles race axles you are looking at?

Raxles - Raxles Home

Just call Marty and talk to him about them; they carry a LIFETIME WARRANTY. He would always replace my axles for FREE; I would just pay for shipping.

I have broken 7 sets of the Raxles standard axles, and have not damaged my new RAXLES RACE axles since installation. It was well worth the upgrade, and the extremely good price.

If you are putting down real power, the RACE axles are the only way to go.