V8 87 RX7 help
 

I'm new to the forum, it looks like a great place for all kinds of good information.

My son and I have purchased an 87 RX7 that the guy had started to install an LT1 engine, he lost interest, ran out of monay and was moving.

The car has the Grannys speed shop subframe, a 97 LTI, 4 speed electronic automatic, aluminum radiator, and a bunch of parts. None of the detail work was done like wiring, tubing, hoses etc. Just the big pieces were installed. The price was less the cost of the just the motor and trans.

The car is in fair shape, I think it's the SE model, it has the 4 bolt axles. My question is before we get too involved with this should we look for a different doner car? Is there a difference in the drive train, the 5 bolt rear axle?

I hope I don't offend anyone by posting this, we are bastardizing the car but it should be something different.

Thanks

let me say welcome! you may be rassled for doing this to and RX, but most people don't care. I would personally love to have a V8 RX7, but i woud stuff it in an FB instead. good find and good luck, make sure to keep us updated with pics!

This is truly a great forum, but in your special case, I think it would serve you well to also try out www.v8rx7.com Some VERY knowledgable people there.

Steve

Other engine subforum:
https://www.rx7club.com//forumdispla...e=&forumid=118

haha i just saw your name. is that your real name or are you making a reference to mike hamar, the handyman on the red green show? :D

You can get a set of the 5 bolt hubs (it's not the axles) and do the swap. If you are tackling a v8 project then this swap is small beans in comparison. Don't waste time/money looking for a different body.

Or you could just answer the question... This isn't a v8 specific question, it's an FC specific question. The other forum does have more info specific to the install, but we can still answer any other question you might have about the stock parts.

I don't have the first clue what's involved with a V8 swap, and neither do the majority of the users who surf this forum. He's better off getting opinions from people who do. Uninformed opinions are worthless. We don't know if he has the proper drive train components(do NA parts hold up to the torque of an LT1), what other parts on another model RX7 would be beneficial to a v8 swap etc etc etc. This is very much a V8 specific question.

Steve

People have gone low 11's on slicks with the N/A 7" rear end( with V8-V6 motor swaps), so if you aren't trying to go faster than that you should be ok. If you want mid 10's then you need to look into getting a TII 3rd member. It is an 8" rear end and is currently in the low 9.3x's on a couple cars running 1.4 or so short times.

Thanks for the responces this is great.

My question was the remaining drive train, there is no difference in the rear, just the bolt pattern. Changing hubs should be easy, are they readily available?

I'll still keep looking for a car with a blown motor, sorry to say this but they seem to be rather available, with a good interior and 5 bolt hubs and save some work. The interior is ragged in the one we have and the body needs some work, to pull out the subframe can't be that much work. We are going to pull the drive train out anyway for easy access to the firewall for the wiring mods running new fuel lines, brake lines and such, heck and just to pant it the proper color. To pull the motor and stick in a new chassis in good shape might be just as easy now.

As for the name its real, Its too hard to remember all the names and passwords you're supposed to have for all this computer stuff. I try to keep this simple and clog my mind with out useless info, like what did fish smell like before women started to swim.

:rofl:

to (partially) answer your question, the N/A differential is not very strong, but you will probably spin your tires before you do any damage. With more traction, you could snap it, though.

One thing you should take into account is that your car has an open differential, whereas the turbo diff is limited-slip. There are also N/A LSD differentials.

What kind of driveshaft is on the car now? Or is there one at all?

The drive shaft is new in a box, its an aftermarket, it just need the yoke to fit the chevy tranny.

So I should look for a turbo car that or the differential from one.

I know little about the RX7, my son came across the car we thought, neet project lets do it. I've ordered a service manual on CD to start and plan on reading as much as I can here, so any tips would be apperciated. I've started a photo book I'll post as we go.

If you want to do it the right way, get the Turbo II differential with Turbo II drivesshafts(they're much thicker). Also, you might look for a 87-88 Turbo II differential, as they used a clutch type action instead of the viscous that the 89-91s use(assuming you are dragging this car).

Steve

You'll need a new driveshaft for the TII rear though. Different flanges.

Swapping out to a Turbo rear sub-frame is fairly easy to do.....10 bolts if memory serves me correctly.

Then you get the half-shafts, rear diff. 5-lug hubs and everything.

The new driveshaft should be sufficient then, for the project.

You can swap out the front 4-lug hubs/brakes for the beefier 5-lug, 4-piston brakes that the TII had, and some NA models.

You will come to find out that most mechanical/interior/exterior parts are interchangable between N/A and TII. There are exceptions, but when isn't there?

Go ahead and shoot any and all questions to us, b/c I may be doing this conversion to my RX in the future (if the motor blows again anyways)

How are hubs affected by a v8 swap? Aside from maybe shearing the 4 lug hubs off with the v8....

The hubs were "one" of the things he was concerned about. Listen, I'm inclined to agree with you, I don't see any problem with just using the existing chassis either. However, one of the biggest hexes on this forum is people who don't know any better posting information that could be misleading or incorrect. Fact of the matter is, if one hasn't done a v8 swap or know the intimate details of doing so, one probably shouldn't be replying to this post. This goes for any subject. I'd rather not contribute to that problem, which is why I posted the link.

Steve

Good info so far, as said before, your best would be the Turbo Axles and differential. Really the N/A rear end isn't very strong, and from what I have seen on the www.torquecentral.com forum (thats the v8 rx7 forum) they almost instantly snap or break very soon if you have around 250 torque, it's really the torque that kills them. Do the project once instead of twice, either find a nicer non-turbo car and swap the turbo goodies in or swap the turbo goodies into your current chassis. Good luck!

This is going much better then I expected.

Who knows where I can get a T11 rear sub frame assembly?

Check the "Parts for sale" subforum, partstrader.com, ebay, etc...you're bound to run into one somewhere!

off to other engine conversions

Yep this is where it need to be. to answer your questions, pthe NA rear is plenty strong for even a higher horsepower LT1, and with an auto trans it will damn near live forever with the near stock LT1. The only downfall would be if the SE has an open type rear, as opposed to a limited slip type. With an independent rear suspension, it covers up the one wheel spinning of an open diff, but if a budget is in mind the NA diff should be used, either way if you switch to the Turbo II Diff you will have to get a different driveshaft mounting flange, which you will have to do anyway. If the SE was an auto it will more than likely have a 3.90 gear which will be better for the LT1. The TII diff has only a 4.10 option and will put you around 3000 rpm at 62 mph with a 25" tall tire and a .70 overdrive(in the 4l60 or 4l60E) The brakes on the TII are bigger, but the se brakes are what quite a few SCCA racers use with aftermarket pads. Either way you can buy struts and springs and still do the 5 lug swap afterwards, they are the same. As posted before, visit torquecentral and all of your questions will be answered.

Hey Mike,

My dad and I are almost done with the same type of project. We got an 86 rx7 (GXL) off of a kid who was half way through and ran out of time and money. Unfortunatly, I've spent most of my time undoing his "jerry rigged" wiring.
Anyways, we're putting a 383 with a 2004r tranny in the rx7, and I think the biggest obstical left is going to figure out how to make a mazda auto shifter "talk" to a 2004r. The mazda's shifter only had 1,2,3,N,R,P... But luckely for us a 2004r will start out in 1st gear and shift to second if you have the tranny in second to begin with. (we also have a 95 saberban with a turbo350 trans I think... if you pull it down to second, the car will take off in second, not first)
So you might want to check and see what you're trans will do without a 1st gear option for the shifter.
Anyways, my point I guess is that If I could start over I would have gone with a stick, even though I like the auto for drag racing better, a stick would have been easier to do (by the way, our rx7 was born a manual)

Also, for anyone reading, we have a LSD in our rx7, and before we put a TII rear end in it we're going to break our stock rear, as in, if it aint broke, don't fix it. We're going to see just how strong these rears are. Every other person we've talked to said rear will snap the first time we floor the car, or it will hold up just fine.
Our motor makes 375hp @ 5,000rpm and 460tq @ 3,600rpm. We'll find out if the stock NA rear is strong or not by the end of the first day we get it driving! :)

we'll let eveyone know what happens,

Good luck with the project!
Brandon