Kaaz + 300m axles enough for 650+Hp?
 

Right now i'm at about 445rwhp, stock rear end. I've never launched it or gave it WOT for fear that the rear is going to explode. I have 305' nittos on the rear.


Anyway, i'm forging the engine and putting twins on it this winter so i'll surely be above 600 HP. Is a Kaaz and 300m axles enough or do I need more? I was thinking about going to a cobra IRS, but they have tons of wheel hop issues with those things.

sorry guys...

anyway there are many solid rear or 8.8 kits out there.

go to www.v8rx7forum and research a bit a bunch of guys over there have done the swap.

Look into JimLab's posts.

I think he was working on a tubular rear cradle to accept different rear ends.

Also look into the Quaffie (sp?) ATB diff. (automatic torque biasing)

Really, my thread title is wrong. I just want to know if anyone has taken a kaaz and upgraded axles up around that power level successfully.

The Kaaz and 300m axles should handle 600whp just fine. However, if this is going to be a dedicated drag car, go with a solid rear.

Yeah I would think it can handle it, it's a clutch style so it's not going to break just eventually wear out, I believe you can adjust how tight it locks up too. Are the nittos drag radials? If they are still street tires then the tires will still break lose before the rear end and axles give way. You might want to reinforce the ppf, get a tranny and differential brace and solid mounts. Thats how I have mine at 500+ and it feels nice and solid. Tires are my biggest limiting factor now.

What wheels/offset are those? And what fender flares? They look nice.

They are the 555RII's the road race radial. Basically the same tread/compound as the drag radial with a stiff sidewall.


Sounds good though, thanks for the opinions. I just didn't think it was worth it to go the cobra IRS route.

Where are you reading about wheel hop issues with the cobra IRS? I have one in my FD, and while I dont have alot of experience with mine personally, everyone who Ive talked with who does have the cobra rear, lack of wheel hop compared to the factory IRS is the 1st thing they comment about.

I think that's a bushing/tire issue. I personally have zero wheel hop after changing to solid diff bushings.

I came from the mustang world, riden in a few high horsepower cobras. Pretty much a well known fact that they have some serious issues with wheel hope as opposed to a vette IRS.

The wheel hop issue can be easily corrected in the Cobra's (it's all in the factory rubber bushings) My buddy has a high 600whp 03 cobra with 315 Hoosiers out back and he has 0 wheel hop issues. You are most def going to want to swap out to the 8.8 IRS rear (look at the setup Samberg sells on the V8 forum). His kit braces the diff at 4 points through polly bushings. 3.90 gears won't work on our kind of power/torque levels, let alone 4.10s, with the 8.8 you have the option of 3.73s, 3.55s, and 3.27s. And as far as Mustangs breaking their IRS, look at their weight, plus the fact that thy're all twin screw/roots blower cars, compared to our light ass cars with some turbo lag

Of course we all know that any IRS car can suffer from wheel hop under certain conditions, but differential mounting and suspension geometry can come into play as well. With good bushings and toe links/trailing arms in my factory FD IRS I had very little wheel hop, though under certain conditions it did still arise. Once at the track it hopped so bad it made me cringe. I decided to upgrade to the cobra 8.8 setup from there, as it has a much more solid diff mounting as opposed to being tied to the PPF which can allow the diff to twist upward at the rear. Ive also been in a friends C5 vette that had horrible wheel hop.. no car is immune to it. I know that the general consensus from guys on here as well as v8rx7forum, is that the cobra swap with good bushings about eliminated wheel hop issues in our FDs.

On a side note, czwalga00gt I see you are local.. I want a ride :D

Haha, do you attend any local car shows? I was at the starlite cruise in wexford yesterday. It was crazy probably 1500 cars.

Havent been to a show in a while.. My FD is in a million pieces right now, seeing other cars just makes me depressed.

I know the feeling... I was without a fast car for 1.5 years. Sold my mustang to build this rx7, and it took me 1.5 years.

Nice transformation though: http://only-here.net/carpics/rx7.html