Hey guys! I'm looking to build up an RX-7 for autocross in STS2, and I think a GTUs is the ideal starting point. If I do find a nice one in good shape, I'll have to make sure it's 100% like it came from the factory to make it legal. Also, if I can't find one I might try to take a non-GTUs and convert it. In that case I really need to have all the differences nailed!

Here's what I've found, lurking here and searching the web:

-Wiperless hatch
-No sunroof
-AM-FM radio
-Fixed steering column
-Crank Windows
-Manual locks
-Cruise control Delete
-Turbo II Brakes
-Turbo II specific spring rates/shock valving
-Turbo II Specific anti-roll bars
-GTUs/SPort specific Aluminum hood
-Turbo II specific door jamb sticker for 205-55-R16 tires
-Turbo II specific 16x7 Mesh-style wheels
-Fog light Delete
-A/C optional
-GTUs Specific 4.30 Viscous LSD
-GTUs Specific half shafts
-GTUs Specific revised Transmission Gearset

How much of this stuff came on the GTU? If the halfshafts, rear end, and transmission are really all GTUs-specific, then I really need to just find a GTUs!

Yes, I saw the FAQ with the brochure, but it's light on detail. I really need to confirm every option.

Any help is greatly appreciated!

-Phil

EDIT: were the rear seats an option on the GTUs?

 

rear end, tranny is GTUs only

halfshafts are NA halfshafts

I'll be selling my GTUs in June if you're still looking for one, but it has a dealer-installed sunroof. It's pretty much stock outside of that.

2+2: not that I know of, it could be dealer installed, you can always install them if you found a set, they interchange with the bins.

 

i believe that the half shafts are the same, but not too sure, if you're going to swap a GTUs diff. might as well swap the whole sub frame. also i heard that GTUs have different gearing in their trannies, but as far as i know all S5 N/As have the same tranny. everything else is pretty much right. you can get any aluminum hood from a S4 also, doesn't have to be off of a GTUs, they're the same thing.

 

I believe the convertibles also came with an aluminum hood.

GTUs Tranny has a .752 5th gear, which is different from what the brochure says. (Mazdatrix)

 

OK, I've done a LOT of reading!

How much lighter is a GTUs than a normal '89/90GTU? How much lighter is an '88 or earlier car? I don't care about published numbers, I need real data from people who put their cars on the scales.

I found another "GTUs only" list:

Aluminum hood
Strengthened TurboII chassis
No sunroof
Crank windows
Hatch wiper delete
TurboII mirrors (aerodynamic)
Sparse cloth interior, little sound deadening
Variable power steering
4.33 rear end (vs 4.10), Viscous LSD
Aluminum control arms, big sway bars, higher spring rates/shock valving
16x7" lightweight wheels (16lbs), room for 245's (265's in rear)
4-piston calipers
Weight as-delivered with full tank, jack/spare, etc. 2721lbs (vs 2890-2965 for other GXL models)
Series 5 engine 160hp vs (146hp Series 4 engine) with only 2 catalytic converters.
Aluminum flywheel
DTSS (rear steering, I like it!)

The light stuff is what matters to me. Does a '90 GTU have the flywheel, control arms, and only 2 cats?

 

DTSS is standard on all FC's.
I don't think the GTUs has an aluminum flywheel, at least my doesn't, it comes with a stock flywheel which is the same as the rest of the S5 NA's.
Some GTUs had dealer-installed aftermarket sunroofs (like mine)
The chassis is the same as the NA, and I think there isn't any difference between the Turbo or the NA.
The suspension is different though, where the GTUs got the turbo shocks and sway bars. I believe springs were the same across S5's.
There is very little sound deadening.....you can hear almost everything.
I'm not quite sure about the control arms, they may just be the same as the rest of the S5's.
Room for tires is the same across all FC's, it's not like the body changed with the GTUs. With a repaint, you wouldn't even be able to tell it's a GTUs on the outside.

 

i know alot of ppl go nuts over the GTUs but if you want a LIGHTWEIGHT FC then stick with the NON sunroof S4s.

The GTUs is a lighter NA that was supposed to get a 3 rotor (according to Mark and his Lit.) but in the end they couldn't meet certain criteria/standards so they stopped production and the one that WERE made received the anemic NA motor.

If you pay MORE for a GTUs than you would another NA then you're not very smart. It doesn't matter that there were only a little over 1000 GTUs' made because in the end it's just an NA.

you will end up spending a buttload of cash to make an NA into a SLIGHTLY cooler NA when you could build a kick *** auto-cross car that will weigh less and possibly COST less. In the end it's your money and you will spend it how you see fit but it doesn't seem like a smart idea.

 

i have 1 1990 GTUs im trying to get rid of. It has a blown motor.....chassis only has 88k on it. Blown motor has like 38k on it. A couple mods here and there....some suspension, exhaust, etc. Person before me had aftermarket sunrof installed. $2000 OBO. Let me know.

 

I'm not allowed to modify it very much in STS2. If I can spend $1000 more to have a car that's 100lb lighter, that's completely worth it. I need to have it come just as it was from the factory, which means if I get the early, lighter S4 I can't get the bigger S5 power.

Now, if an S4 GTU is much lighter than a GTUs, I'll probably want to go that way. Does anyone have numbers?

 

the 5 spd. 1986 NA is quoted at 2625 lbs

the 1987 non turbo 5 spd. is 2700 lbs

the 89 GTU(base) isquoted at 2800lbs

91 coupe is quoted at 2787lbs

http://www.mazdamark.com/about_the_fc.htm has this info and you can find this link in this thread:

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/specifications-what-did-2nd-generation-rx-7-come-w-options-standard-features-249616/

and that thread is in this section: under "stickies"

https://www.rx7club.com/forumdisplay.php?f=17



can you remove bumper supports and sound deadening in the class you're trying to enter? I would recommend you find a 4.30 rear diff in order to help with your times but the gearing difference only changes the 1/4 mile times by 2 tenths of a second so if those .2 secs are worth 600bux then find a GTUs tranny and diff.

 

The extra 14 hp and measly 2 lb.-ft. of torque of an S5 WILL NOT make for a better autocross car.

Get an S4 Sport or ’88 GTU and you will have the best NA, performance wise for autocross or even DD use.

 

A guy I know weighed his 90 GTUs at 2470 with only lightweight battery and exhaust for weight reduction. Can you get an S4 GTU that light without removing anything besides battery and exhaust?

 

i don't think the exhaust and battery weighed 230 lbs. so no, not with the same weight redux as that guy.

you have to remove many things in order to be below 2500lbs.

show the guy you know this link:
https://www.rx7club.com/showpost.php...7&postcount=10

and let him know HIS car is heavier than what this guy^^^ started with.

https://www.rx7club.com/showthread.p...ight+reduction


https://www.rx7club.com/showpost.php...39&postcount=7

now I posted the weights of the cars and you can clearly see that an (1986)S4 BASE, SE/Sport are the lightest models. From your posts it DOES NOT LOOK LIKE WEIGHT plays as large a role as the actual model ( you seem to be dead-set on getting an S4 GTU or S5 GTUs) so just get what you are looking for and gut it and hope it's enough to be competitive.

 

if you need any more info then I hope you search because I have given you more than enough resources to help you make a good decision. All the stuff I posted was found VIA THE SEARCH feature btw.

 

Sure he did.....

 

unless you really have your heart set on a GTUs you'd be better served with an 88 GTU or like an 86 base, and then swap in an LSD. You will have to drop the LSD no matter what because stock differential mounts will not hold up for long