Nick-7

I was wondering if the chasis of an 81 rx-7 is storng, if it can handle drag racing and fairly high horsepower with a role cage of course. I have acquired a real rough 81 that has a blown motor and am using it as a parts car. Once I get the parts I want I was thinking of trying to convert the rx-7 into a full time drag car with a v-8.

Oh no, I said RX-7 and v8 in the same sentence!!

If I was to do this project I would like to keep the price fairly low, thats why I chose the v8. I know the conversion would cost the most with the drivetrain having to be able to handle the extra power and v8 fit in the hood, but if I could fabricate some mounts I think it might be cheaper.

Please give me some ideas and suggestions about what I need to do and how much it might cost.

V8kilr

its extremely strong when in good shape,

i wont knock you on the v8 thing but i will say i decided not to go v8 because i just bought an rx7 because its an rx7,
without the rotary its no longer a rx7.

i still have to find a car to put one of those new chrysler v6's in with the autostick,
you know the one in the stratus r/t

rated @255 hp with aftermarket exhaust
tested @ 285 with aftermarket exhaust and piggy back fuel computer
tested @ 305 with aftermarket exhaust,piggyback computer,new ignition components,and new fuel injectors

can we say fast?

image what you could do with 305 hp and huge amounts of torque with very little weight in an rx7.

i just refuse to do it,
i will do it to a mx3 instead

Nick-7

How much do you think that motor would cost. That is awesome horsepower for a v-6. Chevy has a new v8 that is in one of their suv's that puts out 280 hp stock.
I wanted a v8 because thay are common and parts are everywhere, but I did not like the weight of them.

Yes I do like the rotary engine and I have an se that I love and will never let it cross over to the dark side, but I just love the thought of a car thats less than 3000 lbs and over 300 hp.

Kerry

I don't think you'll have any body problems is you use a cage and tie it in well. Depending on how much traction you get, you may need to address the rear control arms (links), they seem a bit light. You'll definitely need a stronger diff for strip use with that much torque.

82streetracer

iTrader: (1)

V8 killer, I almost bought a Mx3, you can swap in the 2.5L and you dont even have to change the computer.

I had planned on doing that swap, but I lost my job and was unable to get the car.

MikeLMR

I missed out on an MX3 with a blown engine that was being sold for £5 ! gutted I didn't find out about the engine swap till a month after + I had no where to keep it at the time

Defprun

Ford Festiva with Mazda 323 GTX motor in it. It will fit with little mods to the bay and it gives you about 230hp in a car weighing far less than a 7. And, since a Festiva is a Mazda 121 in Japan, there's no blasphemy going on.







Low 14's!?

Acuspeed

I'm not knocking V8kilr's idea about the V6, however, if it were me wanting to go w/a piston motor in my 7, I'd stick w/the V8. Basic reasons would be that there are a fair amount of people that have done this already that might be able to help you out, it's usually not too difficult to get power from Chevy or Ford V8, and there are conversion kits on the market to help limit (at least to some extent) the amount of fabrication you need to do.

If you are serious about this, listen to Kerry and a couple other members here as they have "been there, done that" and can help you around some possible unforseen problems you may encounter.

Defprun

Is it a MAZDA V8?

Manntis

Is the chassis strong?

The day I bought Pamela I hit a patch of ice. I smashed into a concrete barrier @ over 100 kph... and was able to back up and drive away, travelling another 1500 miles home before I got the damage repaired.

That long nose has about 2 feet of deadspace before you even touch the radiator. and I didn't so much as pop a hose.

MikeLMR

Ford fiesta's (our name for 'em) are common as muck over here ... sacralige to waste such a nice engine on a POS ford *LOL* ... + some models come with turbo's etc. as std. in the UK

now an MX3 with a "proper" V6 in it ... not that weedy 1.8 version would be sweet mmmmmm 165HP and 162lbsft in an MX3 quite a sleeper !

Manntis

now now, Mike - you guys also have Cosworth Fords over there, whereas we have to make due...

REVHED

I wouldn't say the chassis is very strong... in fact 1st gens are known to have fairly poor torsional rigidity. This is were strut braces and cages really help.

REVHED

Cosworths... We used to get the old Sierra's here years ago and now it looks like they'll be bringing the Focus Cossie over.

Manntis

yeah, but you Aussies already have cool cars galore...

diabolical1

iTrader: (3)

yeah ... you'll probably need some bracing, but that's just common sense anyway, but i've seen a few Rx-7s with 8's in them and they handle it quite well!

Defprun

Why the hell do you think I chose a Merkur XR4tiover a Festiva??!?!?? RS500 baby!!! WOOHOO!!! Cossie all the way...if anyone wants i can take pictures of it when i get the body kit and dual over head cam conversion...
Maybe a long time my car is hurting! I can take some pics of my car right now if you like, its got 3 inch exhaust and the front grill it off!

Spieder

From what I've read, the 84's to 85's have slightly stronger chassis and weigh a good deal more. A stock 83 is a 8.5 or so car and a stock 84 is a 10.4 car (no power anything). As for torsional regidy I read RX-7s had better than average rigidy. I think it was something like 4700 KN per degree. However, I don't think you'll turn any car into a dragster with out some heavy frame support. The RX-7 only has 3 bolt points for it's power train (as I remember). Two 45 degree mushroom pots and a cross arm up under the tranny.

I would be more inclined to put an MX-3 V6 into it or maybe a Miata engine and tranny since they use a power plant frame system in those.

onepointone

www.grannysspeedshop.com

my dad is on there with his chevy 4.3 conversion in his second gen. (Mike Garcia's second gen with a 4.3/2004r transmittion) some of the first gens on there are beast. i was tempted for awhile to do it to my car. but lacking funds, and i like the rotary too much. but my god.. when i drive my dad's car, that car will plant you to the seat. he has alot of money and time into it. it took us about 6 months to do. and he fabricated most of the stuff. its a cool car and gets lots of attension, and deffinately lots of torque.

EL PAALO

Why would you go with the 165HP KL_03 U.S. Probe/MX6 engine when you can get the 200HP KL_ZE JDM engine for basically the same price? Check http://www.probetalk.com/ for info on the KL_ZE. There are quite a few MX6 and MX3 guys there too.

Keaponlaffen

I notice V8's are getting a little less flaming now... maybe it's starting to set in that they're not as evil as they appear to be?

Jeff

gamble302

v8 rexes and v8 rex owners arent evil at all yeah. kerry is way up there on the coolest car guys around i've met list. right up there with my sister in laws dad who used to race cars and has heard a 787b in person

Defprun

V8's are still evil, I'm just tired.

I think all you dumb V8 guys are stupid.

MikeLMR

sorry, but I dislike most FWD Fords ... they are usually prime targets for "ricers" in the UK ... kinda puts you off them when every other ones sporting a triple decker wing

Cosworths and old RWD fords are another matter

I'm supprised ford never exported the cosworths in larger numbers ... maybee they were too good to let go

Defprun

I think it was probably a good idea (and this is from me) but in a business aspect. They advertised the XR4ti HORRIBLY and instead of calling it a ford they called it a Merkur trying to get the luxury crowd...but saying its sporty and stuff..and it was even expensive for the time. If they would have imported the Cosworth here for a couple grand more (YAHOO!) we could all be enjoying cossie's.