luis911

iTrader: (2)

Hey guys I have the Driveline(Flywheel, tranny, diff etc.) of an s4 TII that I might put on in my 1989 gxl. Question is Wil I have more power(quicker acceleration) With this setup or will that added weight of the flywheel cancel out any gains? I mean Who else has a setup like this on their NA? My car is at 70mph at 3000 rpm on 5th gear, and the transmission that is in the car is from an S4 NA. So yea guys what you guys think?

jjwalker

The flywheel will not be noticeable really, it is only slightly bigger. As far as the tranny, the gear ratios are lower, so you'll actually gain some acceleration, but lose some top speed.

luis911

iTrader: (2)

top speed which I will never use in New york so that sounds good. But ummm that flywheel that I have for the s4 tii Is really heavy, feels like 30 lbs or so.

luis911

iTrader: (2)

is it worth the trouble to install that driveline?

RotaryRocket88

iTrader: (7)

You'll get to dump the POS NA transmission, which will be the largest benefit. No more wimpy synchros. But the TII trans and rear end also weigh more, so you'll really end up being a little bit slower. Not that you'll notice it.

texFCturboII

iTrader: (17)

Getting a lightweight flywheel will help. Also, since you have GXL you already have a limited slip differential. So if you get the mazdatrix custom driveshaft that mates a t2 tranny and a NA rear end, then you'd save some aformentioned weight....

luis911

iTrader: (2)

1989 GXl doesnt have an LSD to my knowledge. What I want to know is if the gear ratio will Quicken up my acceleration and by how much would you say. noticeable difference?

2_3D_SC

All RX-7's came with a 4.10 gear(except the auto trans and GTUs models) so you will not gain anything in acceleration.

But as RR88 said you get a much stronger transmission.this may help you decidehttp://www.mazdatrix.com/faq/ratios.htm

luis911

iTrader: (2)

Yea and Plus I would get an LSD which would be a benefit and a change in driving characteristic right? Down the line I plan on putting a turbo on my GXL, Is it a good Idea to do that with a high compression motor? I wouldnt be putting more than 9 psi tho, Just a turbo to give it torque and use the same ecu and stuff.

pistones

iTrader: (5)

hey Luis i am sending your bolts.

AGreen

iTrader: (11)

and except the convertible... booooo 3.90... boooo!



Anyone want 3.90 diff? $25 with customer pickup

luis911

iTrader: (2)

Cool, I've been cleaning all those parts up and spraying em with high temperature silver paint so It can look good. I got everything except the starter, clutch, and clutch pump i believe its called.

Evil Aviator

If you want a quick non-turbo car for up to about 200-230hp, keep the NA driveline. A Mazda race shop can modify the NA transmission to make it stronger if needed. If you need to change your differential gearing, you can install a 4.33 ring and pinion, or retrofit a 1Gen short pinion 4.44, 4.875, or 5.125.

If you plan on adding a turbo and going past the 230hp range, then you may as well go ahead and install the TII driveline now because you will need it. This would be a good time to bite the bullet and change out all the worn mounts and bushings.

The problem is that all the good racing light flywheels are made only in the NA diameter. Besides, the decreased diameter helps reduce inertia. For these reasons, my TII transmission was specially modified by SPiN Racing so it can use a NA flywheel and starter.

luis911

iTrader: (2)

Keep in mind that im an 18 year old college student who works in construction during the day. so all the fabrication I do myself, no money to pay mechanics Forget those guys. I do **** myself on weekends.

Evil Aviator

In that case, don't perform any maintenance unless absolutely necessary to keep the car running reliably. Your time is better spent studying and networking, and your money is better spent on school-related items or saving up for your impending big move to your first job in your new career. If you like fabricating, I suggest helping your classmates waste money on their cars. You can waste time and money on your car once you are established in a well-paying job.

nitronatefc

iTrader: (2)

The FSM shows that the gear ratios are as follows:

S4 TII-------------------------------S5 GXL
1st- 3.483-------------------------1st- 3.475
2nd- 2.015------------------------2nd- 2.002
3rd- 1.391-------------------------3rd- 1.366
4th- 1.000-------------------------4th- 1.000
5th- .762---------------------------5th- .756

You decide which ratios you like better. The TII diff and trans definitely do outweigh the NA parts, but are stronger. In stock form, the swap probably isn't worth it. Performance would change more drastically with a rear end swap. You would have quicker acceleration/ lower top speed/ worse fuel mileage if you installed a 4.3 rear diff from an S5 GTUs model. You could easily afford one of these by selling the TII driveline you have. None of the 3.9 convertible rear diffs came with LSD, but would give you slower acceleration/ higher top speed/ better fuel mileage if installed.


Your right. Only S4 GXL models came with LSD. Here is some other good driveline info from the FAQ:

Suspension & Driveline (including transmission questions)
Can I install the Turbo II transmission into an NA?

Certainly. But you need to also install:
-TII flywheel, clutch, pressure plate
-TII slave cylinder
-TII starter
-TII driveshaft, differential, axels
-Adapt the wiring.

MazdaTrix makes a TII transmission to NA rear end driveshaft, so if you don't want to swap your rear end, you can use that shaft instead.

Can I install the RX-8 6 speed transmission into my 2nd Gen RX-7?
5th gear on the FE tranny is the same as the 4th on FC trannys anyway, so there is no real advantage of using the RX-8 tranny if you are thinking that the 6th gear will be a extra gear for an overdrive, and actually 6th on the FE tranny (.83 vs .71) is shorter than the FC, resulting in lower gas mileage at highway speeds.

Using a RX-8 tranny would be like adding a extra gear between 2nd and 3rd to a standard 2nd gen RX-7 M or R type transmission. If you look at the gear chart this does not match clearly, but in simplified operation it is the nearest description to what happens.

Add in, that the RX-8 6 speed transmission is also about 4 inches too short, forcing you either to relocate the shifter 4 inches forward in the car, or move the engine 4 inches backward (towards the firewall) to make it fit in the stock shifter location as well as fabricate a custom drive shaft and transmission mounts.


Did my 2nd Gen RX-7 come with a Limited Slip Differential?
Only the following USA model 2nd gen RX-7s had a LSD from the factory:
86-88 GXL
87-91 Turbo
88 GTU
89-90 GTUs (however not the 89-90 GTU)

luis911

iTrader: (2)

Your right about that but you know how it is man, when your young and you have a sports car you want to go crazy with your car and all that stuff. Im doing upgrades on my car but im taking it one part at a time, once i get everything for a certain section in my car i put em in. So I'm doing it in stages you can say, Stage 1: Driveline, Stage 2: Turbo, and I guess im good with suspension since the previous owner did an upgrade already.

Hmm so i will get different gearing on the tranny. But is 1.391 vs 1.366 a difference that you can feel? I'm not trying to convince myself to do it anymore since im decided, im just curious.

funkjaw

iTrader: (3)

^ Nope, you will not even notice a difference.

Evil Aviator

Check the bushings. Most people don't replace them because the old ones are extremely difficult to remove. That, and the bushings are not as flashy as shiny new springs and dampers, so they often get neglected. The same goes for mounts and exhaust hangers. Neglect the bushings and mounts and your nice, new parts will quickly become old broken parts. Even the best suspension parts in the world will drive like garbage with torn-up 20 year old bushings and mounts.

Choosing gearing is rather complex, you are really supposed to use a dyno sheet, and many people argue about torque vs. horsepower for a given application. However, here is a ghetto example simply using a power band between typical peak torque and peak horsepower numbers just to show you the difference:

Assuming:
Power Band = 3500-6500rpm
Differential = 4.10
Tire = 205/55R16

S4NA
1G 18-34mph
2G 32-59mph
3G 46-86mph
4G 63-117mph
5G 91-168mph

S4TII
1G 18-34mph
2G 31-58mph
3G 45-84mph
4G 63-117mph
5G 83-154mph

BTW, your speedometer and/or tachometer is off unless you have some really small wheels.

In his first post the OP stated that his S5 car currently has a S4 NA transmission, which has a .697 5th.

Black91n/a

DO NOT USE THE S4 FLYWHEEL ON YOUR S5. This will make your engine unbalanced because the S4's required more weight to balance due to the heavier rotors. You need to get an S5 flywheel or a lightweight one and an S5 auto counterweight.

Not quite, I've seen TII sized 5.5" clutch stuff available from Guru, but tha sort of thing will be terrible on the street. There's some nice lightweight stock size flywheels out there for TIIs. I think that with the ACT Prolite, due to the void space at the periphery, may well have less inertia than a lighter aluminum flywheel with more of its weight at the periphery, even if it is an NA sized one.

I gather the old RX-4 and such used the NA sized flywheels and the TII style transmission, so their bellhousings can be used so that you can have a TII transmission and an NA sized clutch and flywheel.

Evil Aviator

The only Guru TII flywheel I have seen is the 4140 model which weighs a whopping 10.1 lbs. While I realize that weight distribution has a lot to do with MOI, this flywheel is not comparable to the 3-4 lb Billington or Quarter Master racing flywheels. Does Guru make an actual light TII flywheel that I am not aware of?

Many flywheels are designed like that. However, whatever design you use to reduce inertia on a TII flywheel, you can do the same thing to a smaller NA flywheel and get even better results. For example, the Tilton steel TII flywheel is 9.5 lbs / 184 MOI, while the NA model is 8.2 lbs / 136 MOI.

Using the smaller NA flywheel with a TII transmission is nothing new. Racing Beat sells a TII-splined 225mm clutch for this very purpose.

I considered that, but it is pretty tough to find the old bellhousings nowadays, and I like my setup better because it can work with either a TII or NA flywheel by simply mounting the starter in one of two positions. Besides, my friend modified it for free just to see if it could be done. No, he is not doing it again, lol.

Black91n/a

I'm not sure, but they may well be counting the weight with the 4lb counterweight whereas the 3-4lb ones obviously aren't, so that could bring them much closer to par.

Again, you're talking about race stuff, I'm talking about OE style stuff, of which there's no comparable flywheel to the ACT one as far as I'm aware. Not many people will be willing to spend the money for and put up with race stuff on the street. I'm not disputing that smaller is better from a MOI perspective, I'm just saying that from what's out there for street use, the TII diameter might not be any worse given the flywheel choices.

Evil Aviator

The Guru flywheel is made of steel. Most light racing flywheels are all-aluminum or aluminum with a steel center.

Yes, I am.

Sure, there isn't all that much difference, but I don't see any point in going through the effort of swapping to the TII driveline for street use unless the extra strength is needed.

luis911

iTrader: (2)

Well like I said I'm upgrading my car little by little. starting with the driveline and then getting into the turbo stuff. I already got all the stuff for the tII driveline so I might as well go with it. I have faith in my car, It has about 50,000 miles and the interior and everything else is very clean. I rather use this car then end up buying a headache that I have to spend money to make reliable.

But one question. whats the most boost you can run on a high compression motor? 8lbs or so?

Black91n/a

Indeed. I'm currently doing the TII transmission swap to get something more durable for the track and to take care of one more thing on the list of support items I'll want to have for when I might eventually get to build a good engine for my car.

I weighed the parts and it looks like I'll be gaining 3lbs on the swap. The TII sized ACT Prolite flywheel with ACT HDMM clutch is 5lbs lighter than the NA stock stuff (counterweight included), but the transmission and driveshaft are each 4lbs heavier. This isn't exact, as it's done on a bathroom scale, but it gives an idea of the weight differences.