Possibly 300 turbo build...

[Anonymous]

I've been toying around with alot of drag/street car ideas for a while. However, there seems to be one coming together in bits and pieces as we speak. I need some input on the thoughts though...
As far as the donor car is concerned, I can get a 1986 Mazda RX7 already stripped down to the unibody. All that's there is all the sheetmetal, glass, bumpers and steering.
The motor has just become recently to the light. I sold a 1984 F150 w/ a 300 straight six in it to my brother in law a while back. Well, I gave him EFI manifolds for it that he never installed. He "blew it up" a month or so back. Turns over but it won't start, no visible external damage to the block. The truck was already running a Holley 350cfm 2bbl carb on it.
I can get a pair of Mitsubishi Eclipse T25 turbos for $60. Both need to be rebuilt, which will cost in the area of $140 total. I can do the rebuilding, I just need the kits.
I'd like to run a manual transmission in it. However, the truck has an auto in it right now... a C4? How hard is it to switch from an auto to a stick? Would a stock C4 tranny hold up very long? Would the T25 pair be good for a "hot" street motor (maybe about 500hp?). I know of course the engine will need a rebuild and proper parts for this level.
I'm still researching alot of the information. I have a Ford 9" rear that I'm going to narrow down and put in the car w/ 31 spline axles and a 4.10 gear w/ 31" slicks (possibly). I can get those slicks pretty cheap, but may just go w/ 3.73 gears and 28" slicks/drag radials.

 

[69Falcon]

While I'm not usually one to object to mixing and matching cars and motors, I'm not sure you have a good fit on your hands. I used to have an '88 RX-7, so I'm very familiar with the 2nd generation ('86-'91). Click here for more about my car.

Engine height can be manipulated with a hood scoop, but the overall length might be a concern. I suspect you won't have enough length underhood to fit the 300, the 13B rotary motor originally in the car is extremely small. Of course, if you're willing to hack up the firewall, all bets are off.

You didn't say if the chassis was originally a naturally aspirated or a turbo model; I suspect N/A because IIRC Mazda didn't bring the TII over until '87 or '88. At any rate, the rearend in an N/A RX-7 will stand a decent amount of abuse, after I added a supercharger to mine I was putting out 210hp/175ft-lbs at the wheels. Dyno Chart I've seen the pumpkin from the turbo cars handle in the range of 300rwhp. If you are seriously going beyond that, you'll have to go with your idea of the 9". That will require you to re-design the mounting of a solid axle, because the RX-7 had IRS.

And if you're planning on driving it on the street, don't forget to wire up the pop-up headlights, which have a history of sticking!

 

[Anonymous]

The interior of the car is completely missing minus the steering wheel and shaft. So, moving the firewall wouldn't be a problem and I can get "scrap" at work for next to nothing. I used to be a fabricator and welder for the same company, so I have access to all their tools.
I had already planned on using the 9" anyway. There's no drivetrain in the car at all right now, it's up on blocks. I'm sure I could fit the engine in the bay, height wise though.
I was checking out compressor maps and stuff, but I wasn't sure how to plot for a twin turbo setup. Would I just take half the cfm required for the motor and plot that then multiply it by two? I didn't know if it'd be that easy or not, to see if those T25's would work.
My biggest concern was if the torque would twist up the RX7 unibody. Also, I was going to mount the rear end with a truck type swing arm design. I've given some though to running 2x3 tubing from the rear to the front subframe for some rigidity.

 

[shmoozo]

I've been toying around with alot of drag/street car ideas for a while. However, there seems to be one coming together in bits and pieces as we speak. I need some input on the thoughts though...
As far as the donor car is concerned, I can get a 1986 Mazda RX7 already stripped down to the unibody. All that's there is all the sheetmetal, glass, bumpers and steering.
The motor has just become recently to the light. I sold a 1984 F150 w/ a 300 straight six in it to my brother in law a while back. Well, I gave him EFI manifolds for it that he never installed. He "blew it up" a month or so back. Turns over but it won't start, no visible external damage to the block. The truck was already running a Holley 350cfm 2bbl carb on it.
I can get a pair of Mitsubishi Eclipse T25 turbos for $60. Both need to be rebuilt, which will cost in the area of $140 total. I can do the rebuilding, I just need the kits.
I'd like to run a manual transmission in it. However, the truck has an auto in it right now... a C4? How hard is it to switch from an auto to a stick? Would a stock C4 tranny hold up very long? Would the T25 pair be good for a "hot" street motor (maybe about 500hp?). I know of course the engine will need a rebuild and proper parts for this level.
I'm still researching alot of the information. I have a Ford 9" rear that I'm going to narrow down and put in the car w/ 31 spline axles and a 4.10 gear w/ 31" slicks (possibly). I can get those slicks pretty cheap, but may just go w/ 3.73 gears and 28" slicks/drag radials.

Hmmm ...

You may need to move the seats back a foot or so after you finish with the firewall adjustments.



It's an interesting project. The Mazda enthusiasts will hate it. The Ford 6 enthusiasts will love it. Everybody else will just think you're kinda weird. As for me, well, I like weird, unorthodox projects, and this one is about as far out on the fringe as anything I think I've heard about in a while.

 

[Anonymous]

I still need a few answers though...

1) How well will the stock C4 trans hold up to a SS (street/strip) turbo 300?
2) Is a manual conversion very difficult and what would it involve? (minus a clutch kit and a trans w/ bellhousing)
3) Would twin T25's be sufficient for say 8psi of boost?
4) What would I have to do to the motor to keep it from puking it's guts out on that boost? What about 14psi of boost? (At 14psi, I'd probably need bigger turbos, a pair of small T04's?)

I love unorthodox projects as well. It's also kind of a loophole in the "import" racing rules. Generally, they state you can run a 6cyl, as long as it's inline. Competition rules are different, but I'm not going to be competitive, I just want to beat up on Hondas and etc

 

[shmoozo]

I still need a few answers though...

1) How well will the stock C4 trans hold up to a SS (street/strip) turbo 300?

I don't know much about that sort of thing, but I do know that you can get beefed up automatic transmissions from a number of sources. Oh, and don't be afraid to use a bellhousing adapter and a transmission from a company other than Ford. There's a lot of companies building beefy GM transmissions, for example, and it may be that one of those would be a better choice for your application.

I love unorthodox projects as well. It's also kind of a loophole in the "import" racing rules. Generally, they state you can run a 6cyl, as long as it's inline. Competition rules are different, but I'm not going to be competitive, I just want to beat up on Hondas and etc

Oh, man, that's a mighty big loophole.

 

[XFlow_Fairlane]

I would backhalf and cage the car. will make the 9" install easier and I am guessing it will need a cage for the track.

I say a manual valved C4 will do the ticket for you.

check on those loopholes.....usually you have to run same make motors....but might be able to get away on the ford/mazda combo which would rock!! I know some of the 2.3T guys love running in import classes (pinto is a compact.....toss in a 2.0L destroked crank to get it in a 2.0L class and let it rip) if you do this I say build it to run a class just to really piss off people.

 

[82F100]

I would use a tranny that has a Street/strip build., and with a auto the car would be more consistent.my thought if you're just wanting to run 8-13 lbs of boost I would run only one turbo.Any Idea of the weight of the car? Looking at the rule book for the NHRA sportcompact series.Bout' the only class you could run at This series would be the brackets as they have .....Engine must be of import manufacture or from domestic-labeled joint manufacture platform.The other classes for RWD you'd have to weigh over 3400lbs and most of those cars are in the mid 8's to high 6 sec zone.Good luck with the project.

 

[Anonymous]

I would use a tranny that has a Street/strip build., and with a auto the car would be more consistent.my thought if you're just wanting to run 8-13 lbs of boost I would run only one turbo.Any Idea of the weight of the car? Looking at the rule book for the NHRA sportcompact series.Bout' the only class you could run at This series would be the brackets as they have .....Engine must be of import manufacture or from domestic-labeled joint manufacture platform.The other classes for RWD you'd have to weigh over 3400lbs and most of those cars are in the mid 8's to high 6 sec zone.Good luck with the project.

I'm not planning on running in anything like NHRA or like that. I'm just talking about the "import shootouts" and stuff like that.
Would it be cheaper to build a C4 or a TH400and run an adapter?

I was planning on backhalfing and caging the car. I didn't say that earlier, my fault.

 

[Funky Cricket]

c4's are crazy tough with manual valve bodies and a decent performance rebuilt. 500+ HP in mustangs regularly.

 

[Anonymous]

c4's are crazy tough with manual valve bodies and a decent performance rebuilt. 500+ HP in mustangs regularly.

If they're anything like turbo 400's, it's nothing I couldn't do myself either. Swapping out a few parts and adding a performance rebuild.

 

[82F100]

Here's a crazy thought...Though it's a six but just not inline, what about a ford v-6 with a turbo in that thing?There's all kinds of used NASCAR stuff around to make a stout motor and you would have ample room in engine bay.

 

[Anonymous]

To be honest, I never really cared for Ford vehicles I've got my flamesuit on for that comment, haha. However, the 84 pickup that I had was one of (if not THE) best buys for the money that I ever got. For $400, replaced the rear main seal and fuel pump... then loaded it up with ALOT of stuff and drove from NY to MO in it.
I get long winded sometimes, anyways, my point is I don't know ANYTHING about Ford motors except the 300 since I worked on it while I had that pickup. Also, I could get that truck back for next to nothing.