alright this is for people who have/had or have ridden/ driven in. i want to see some pics of swaps, and the views of the owner, the pro's and con's of it.

i dont mind if other people share their opinions, but lets keep it professional. No "Your an Fu**ing idiot for doing that" comments. if you have a legitemate point, go ahead and share it, but dont beat the hell out of it.

remember guys, their only cars....

 

This should go in the other engine swaps forum, not here.

But keeping things professional, I think a V8 swap is the next best thing to a rotary in an RX-7. Contrary to what many may believe, a V8 doesn't add a lot of weight to the front end if you pick the right V8. A fully preped S5 TII engine with everything on it can weigh as much as 350 lb I believe. A ford 302 from an 80's mustang weighs in at a measly 50-75 lb more. I don't care what anyone says. 75 lb isn't going to make a noticeable difference in the way the car handles, as far as street and minor track use cars go.

My engine of choice if I were to go for a piston engine swap would be the mid 80's RWD version of the buick 3.8 V6 or the mid to late 90's 3800 V6 from a camaro or firebird. These are one of the most overbuilt engines I know of and can take amazing amounts of boost when turboed. From the factory, the turbo versions of these engines in the 80's ranged from 250hp to 276hp and have as much torque or more torque than a V8. They are also very easy to get over the 400hp mark without even touching the internals. What more could you want in an engine.

 

I have to disagree that 75lbs wont change your handling, this is 75 lbs over the front axle it will alter your handling, in fact you'll need heavier springs to compensate, it will affect your braking, turn in and acceleration.

However for a street car or drag car its not significant, but for a circuit car it'll show.

This is over the weight of a 13BT, what is the difference over a 12a bridgeport or very well done street port.

 

This belongs in the Other Engine Conversions forum.

For those of you who didn't know, piston swap and piston-powered rx7 topics are frowned upon in the main sections, and thus there is a section (Under the Performance sub-heading even) made specifically for it.

Threads like this in the other sections lead to flame wars and people getting banned.

Take this as your warning folks. Thread moved.

Jon

 

well not only that much weight, but the location of the motor, i know the rotary can be placed lower, and farther back. i want to know how much of a difference does the position make. could the car sill be made to handle?

 

This horse has been beat to death. When done right the weight will be 50/50. It is not hard to do as many have done it. They handle just as well as a rotary powered 7 but with more power and WAY more torque for a bunch less money than a rotary of the same power level. The other reason for this swap is the reliability of the engine. Rotaries are not as reliable at similar power levels.

If you haven't had a ride in one or driven one, find someone close to you and go for a ride. That will help you see what others have seen in the swap.

No matter what anybody says, the car belongs to the owner. Do with it as YOU see fit, and enjoy it to the fullest.

 

V8 RX7's are scary fast!

 

I have no idea what an engine swap is. My car is completely stock

 

There is no disadvantage to swapping out the rotary for a v8.

 

Around here deals gap is the test.. and my car is very fast at the gap(and i have 43lbs. to the front cause of my a/c I think)that is with me in the car.. you put a Rx at 50/50 on the scale without a driver and you will be 50 to 80 heavy on the rear when you are in the car, then do a little weight transfer math under acceleration w/ 300 or 400wh and you got a push... I cant drive a car with a push, it scares me to death... My car dives into the corners at the gap with the back out just a little and then when you add the fuel it settles in and bites hard with very predictable front steering, I am still running the stock 13" w/ Khumos.... not the best setup for cornering but they do real well for their size....

 

im sorry, i didnt understand a word of that

 

I have to say that the added 60 lbs is NOT negligable, but it is easy to compensate for such. Relocate your battery to the rear and add heavier springs and boom its in. Also, this could actually make for a looser car for those people like me who LOVE to trail brake into their corners. The v8 is just so enticing to me because it NOT ONLY gives me a chance to compensate for my uhhhh small ****...(jk) but simply because its a cheap upgrade, and parts are available from the local autozone for like 5 dollars. I'm not saying its better than a rotary, not by any means, but its just better for me than the 13b was. Now i just have to keep telling myself I AM NOT a closet redneck haha. my .02

 

Here is my translation:

"Around here, Deal's Gap (a road race course) is the test of a car's handling, and my car is very fast there. It has a 43lb. front axle weight bias with me in the car. A first gen RX-7 with 50/50 weight distribution will end up with a 50-80 pound rear axle weight bias with the driver in it. Summing the moments of the car about its center of gravity when it is accelerating will illustrate how the rear wheels will carry proportionally more weight than the front, compared to a nonaccelerating situation. This can cause understeer (slang term = "push"), which scares me to death! My car turns into the corners very well with a slight bit of oversteering tendency, and when I roll on the gas upon corner exit, the rear tires load under weight transfer due to acceleration, and the oversteer disappears. I am running the stock 13" wheels with Kuhmo race tires, which is not the best setup but it works."

I dunno, I thought it was crystal clear what he meant to say, even if the punctuation / sentence structure was not technically correct.

 

Understeer and oversteer can easily be changed by adjusting the alignment specifications. The biggest handling problem with installing a V8 in an RX-7 is bump steer, just like a 3 rotor, there are a few different solutions to this problem so it is only a problem on a completely home made swap. Any changes to oversteer/understeer bias from added weight can easily be fixed by adjusting alignment and/or spring rates. Every RX-7 racer that I know is impressed with the V8 swaps and a few of them have done V8 swaps into street cars themselves. None of them have ever commented to me about the handling negatives, only the negatives of getting pulled over by the cops by getting addicted to torque or that they can't race in a competitive class with the car which doesn't really matter because they already have a competitive car in their class. The opinions of people who race and win nationally in autocross and club racing mean a lot more to me than the opinions of people who have probably never even competed in a race before in their lives.

 

Almost all of the swapped cars have the engine behind the front wheels *ANYWAY* by virtue of how the RX-7 chassis is designed. Havent you looked at a pic of one yet? lol. Or use the SEARCH button and look at all the people who have bothered to put the car on a chassis scale and find out the weight balance.

Also, yeah, in terms of dynamic performance Id think Kukris heavy, iron SBC with a carb sitting on top like the perverbial cherry spanking a Z06 and a STi kind of proves the point.

Remember, this is a RX-7 - the front wheels are pretty far forwards! Theyre not mounting the engine between the strut towers - its mostly or ENTIRELY behind it - and becuase these cars have POSITIVE caster the wheels are farther ahead than the strut towers ANYWAY!

 

I like your thinking!




My setup is a bit clustered now but I still get 25mpg and ran a best of 11.88 at 117 with a slipping trans.

Mikes old car (has been sold)... Nets about 32 MPG and runs mid to high 10's at 130+ Not to bad for a street car. And I mean street! He dries it to other state tracks and runs. Oh and it's on pump gas. With alcohol injection.




My car weighd in at 2650 with a half tank of gas. Relocated a large forklift bat (70lbs) to the spare tire well and compensate for the extra weight in the front. The car handles great(stock suspension) but I'd like to get it out against a TII in an scca event. With some good tires I think I'd make it look silly. Even with my auto trans.