Well, I was thinking about doing this a while back with my project RX-7. However, it kind of stalled and I was on track to building up the rotary.
However, I'm getting out of the Navy soon and I need to get the car back together to ship it back to the states. And now I'm thinking I might want to go this route since I'm also planning on returning this car to street status (it's currently ultra-stripped).
A nicely-built 4g64 would make a great engine for this car. And with the weight reduction I've done, even after making the car streetable once again it shouldn't come in at more than 2600 lbs with driver.
I need a new tranny and a new diff anyway, so the idea here is to upgrade to TII units as my car is currently N/A. Since I'm doing that, I have the perfect opportunity to get ahold of a B2600 bellhousing and go with a wideblock. I'm also considering sleeving it and using a custom stroke crank. So... if I do get around to doing this, I will be posting a lot more info over the summer (I get out end of June so hopefully it'll start soon after).
I may even have a 4g64 crank to sell. I think I'd also like to try using a massaged 2g head for the stroker to see how well that works out with the smaller ports.
I love this board, keep up the good work guys!
4G64 FC3S (again)
Moderators: DJpowerHaus, mattmartindrift
If this is a turbo II rx-7 you might want to think about gearing those car have 411's in the rear..I think that might be to much gear for a built 2.4, you have traction problems crazy....something to think about!!! my brother has a turboII with a 60-1 and that thing is like drivin on ice with only 8psi!! spins though 1..2...and third!!!
There is always someone faster!!!
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DJpowerHaus
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DJpowerHaus
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Although I think some of what he says is crazy, I've been reading up on the smaller ports and it seems logical. A good port job on a 2G head is better than a good port job on a large port head... more material to play with, more velocity, more torque.
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
Hehe, crazy huh? Well, I prefer to think of it as "outside the box" but I don't blame you.
The reason I want to sleeve a 2.4L is because LA Sleeves makes good sleeves for cheap, and because I want to offset-bore the block. Actually, it probably could be done without the sleeves. But the sleeves are a bit of piece of mind. I'd like to run a 90mm bore and perhaps modify a 4g63 crank for something between the 88mm stroke and 100mm stroke of the 4g63 and 4g64. I'll also have to build a header for this engine...
As far as ports go, I've seen a lot of high-hp engines (forced induction) that don't have huge ports. In fact, I was extremely impressed with the difference cams made on my 2g GSX. The car pulls very hard, even limited by the stock 2g head and intake manifold.
More than anything, I'd really like to use this engine to test some ideas that I've been thinking about recently. The car is basically perfect for them, since I'll have the drivetrain layout and room necessary for all the extra things I'm planning to add. One of the things I'm looking at is removing the need for a crank pulley by alternate means of driving the accessories.
The reason I want to sleeve a 2.4L is because LA Sleeves makes good sleeves for cheap, and because I want to offset-bore the block. Actually, it probably could be done without the sleeves. But the sleeves are a bit of piece of mind. I'd like to run a 90mm bore and perhaps modify a 4g63 crank for something between the 88mm stroke and 100mm stroke of the 4g63 and 4g64. I'll also have to build a header for this engine...
As far as ports go, I've seen a lot of high-hp engines (forced induction) that don't have huge ports. In fact, I was extremely impressed with the difference cams made on my 2g GSX. The car pulls very hard, even limited by the stock 2g head and intake manifold.
More than anything, I'd really like to use this engine to test some ideas that I've been thinking about recently. The car is basically perfect for them, since I'll have the drivetrain layout and room necessary for all the extra things I'm planning to add. One of the things I'm looking at is removing the need for a crank pulley by alternate means of driving the accessories.
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DJpowerHaus
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Just remember the first law of thermo dynamics.... You cannot create or destroy energy.
And about offset boring or whatever its called.. yes.. it might be better.. but for all that effort... is it WORTH the effort? Perhaps you should do a cost/benefit analysis of what you plan on doing. You might gain 5hp by adding a windage tray, but if it costs you $100 you might as well spend that extra money on better cams, a better exhaust or intake manifold... better ECU... etc etc.
Also you'll find much of it is shaped by the deals you find. Here is some cost benefit for you. New Spark plug wires on a system with an MSD DIS4: $70... coil on plug... $40. Benefit... performance.. maybe. As good as the best plug wires could be though.. and they'll last longer.... cleanliness... maybe... but I saved $30 over wires... this is the real benefit.
And about offset boring or whatever its called.. yes.. it might be better.. but for all that effort... is it WORTH the effort? Perhaps you should do a cost/benefit analysis of what you plan on doing. You might gain 5hp by adding a windage tray, but if it costs you $100 you might as well spend that extra money on better cams, a better exhaust or intake manifold... better ECU... etc etc.
Also you'll find much of it is shaped by the deals you find. Here is some cost benefit for you. New Spark plug wires on a system with an MSD DIS4: $70... coil on plug... $40. Benefit... performance.. maybe. As good as the best plug wires could be though.. and they'll last longer.... cleanliness... maybe... but I saved $30 over wires... this is the real benefit.
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
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DJpowerHaus
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For maxiumum high rev power big ports are better and flow more... but not everywhere else on the power curve. Under 5k big ports will only hurt you. Less torque, slower spooling of turbo, etc.
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
Right. Smaller ports can flow almost as well as large ports but with greater velocity, which is my goal. The extra mixing caused by that should also help improve combustion "quality." At the very least, with the smaller ports there is more flexibility to control the size of the ports from as small to as large as needed.
DJ, thanks for the info. I know some of my ideas will be costly to try, but I do want to try some things. That is, I will likely forego some of the costlier stuff. For instance, I've already decided to use a stock 4g64 crank unmodified because I don't see a big enough benefit to changing the stroke.
DJ, thanks for the info. I know some of my ideas will be costly to try, but I do want to try some things. That is, I will likely forego some of the costlier stuff. For instance, I've already decided to use a stock 4g64 crank unmodified because I don't see a big enough benefit to changing the stroke.
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DJpowerHaus
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I wouldn't rule out destroking it with a 2.0 crank though. I've heard some good things about that motor (2.1L with 10,000+ rpm redline). Its still a bolt together affair with a stock forged crank... not some welded and ground crank (sounds scary to me).
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
find a tranny and valvetrain that will live at 10K rpm. its not cheap. if i had to do it all over again i would still do the 2.4. i love my motor. 2nd choice would be just a 2.0 with a 60-1.DJpowerHaus wrote:I wouldn't rule out destroking it with a 2.0 crank though. I've heard some good things about that motor (2.1L with 10,000+ rpm redline). Its still a bolt together affair with a stock forged crank... not some welded and ground crank (sounds scary to me).
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DJpowerHaus
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RX7 transmission... valvetrain shouldnt be too bad with all the amazing evo parts available. Its not like this head doesnt have options. I'm not sure what cams could really take advantage of this though.
Its not like its the first time a head has been built for this type of thing. Is there any particular requirements that would be difficult to meet on even a budget like I like to have?
Its not like its the first time a head has been built for this type of thing. Is there any particular requirements that would be difficult to meet on even a budget like I like to have?
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
I thought I'd update you guys on my situation.
I found out that I am getting out of the Navy early for a medical discharge, which means that my RX-7 will be shipping out in early June. Not a big deal except it's completely DISMANTLED. There's no wiring at all in the car right now, and the stock harness is not usable (I cut it to remove it from the car). No big deal though, I bought a MS-II kit from DIYAutoTune. By the way, I have to say that their kits are really awesome, professionally packaged, and very easy to set up because of the way everything is labeled.
Anyway, I got the MS to get the car running again, so that I can ship it. I haven't finished assembling the MS but it's going very fast; I finished the Stimulator and Relay Board in about 3 hours, and had a lot of fun doing it.
So for now, a lot of the stock parts are going back on the car, with regards to exhaust and such (which actually aren't stock parts, there's a custom downpipe which mates to an HKS exhaust that was on the car when I bought it). This is simply so I can ship it, but I'm working on a rear radiator mount setup so I still have a lot left to fabricate, not to mention windows to make.
I do have a bit of a problem though: I already have a lot of 13b parts. I've got a GT40 turbo with .96 A/R turbine housing, not very likely to spool well on a 4g63 or even 4g64.
I've also got a TII flywheel and clutch, along with a pair of 850cc injectors and 550cc TII injectors, an FD upper intake manifold, and various other things. The original plan was to turbo the N/A motor.
So now I'm left with a conflict. I'm fairly sure my wife would go into conniptions if I didn't use the parts that I've had sitting around for so long now, and I do love the rotary engine. However, I have a feeling that I'd much rather put a 4g into the car.
It would be interesting to try a 2.1L motor, I'm thinking about that with regards to my options. Maybe the big 1g ports would work better on the high-rpm engine? Then again, it's still gulping in an equivalent amount of air to a 2.4L... Lots of math to consider when it comes to that part.
Anyway, so right now I'm working on getting the car back together to get it back to the states. Any suggestions on what to do after that? I'm still not sure whether the car will be a daily driver or not, because I do have a DSM waiting for me in MD. But it has no power steering and that gets old. The RX-7 doesn't either but the effort is WAY less. So despite the lack of interior and glass, I'm actually thinking of making some panels and coming up with some sort of window setup that will allow air to enter the car.
Oh yeah, the rear-mounted radiator setup. I decided to utilize the open hole where the sunroof was. The top half of the ducting will be made with plexiglass, so that I can maintain rear visibility. The rad will actually mount slanted, inside the car, and the section between the tailights has been cut out to allow for exhausting the air. I'm just going to make some sort of sheet metal scoop to cover up the sunroof hole.
I found out that I am getting out of the Navy early for a medical discharge, which means that my RX-7 will be shipping out in early June. Not a big deal except it's completely DISMANTLED. There's no wiring at all in the car right now, and the stock harness is not usable (I cut it to remove it from the car). No big deal though, I bought a MS-II kit from DIYAutoTune. By the way, I have to say that their kits are really awesome, professionally packaged, and very easy to set up because of the way everything is labeled.
Anyway, I got the MS to get the car running again, so that I can ship it. I haven't finished assembling the MS but it's going very fast; I finished the Stimulator and Relay Board in about 3 hours, and had a lot of fun doing it.
So for now, a lot of the stock parts are going back on the car, with regards to exhaust and such (which actually aren't stock parts, there's a custom downpipe which mates to an HKS exhaust that was on the car when I bought it). This is simply so I can ship it, but I'm working on a rear radiator mount setup so I still have a lot left to fabricate, not to mention windows to make.
I do have a bit of a problem though: I already have a lot of 13b parts. I've got a GT40 turbo with .96 A/R turbine housing, not very likely to spool well on a 4g63 or even 4g64.
I've also got a TII flywheel and clutch, along with a pair of 850cc injectors and 550cc TII injectors, an FD upper intake manifold, and various other things. The original plan was to turbo the N/A motor.So now I'm left with a conflict. I'm fairly sure my wife would go into conniptions if I didn't use the parts that I've had sitting around for so long now, and I do love the rotary engine. However, I have a feeling that I'd much rather put a 4g into the car.
It would be interesting to try a 2.1L motor, I'm thinking about that with regards to my options. Maybe the big 1g ports would work better on the high-rpm engine? Then again, it's still gulping in an equivalent amount of air to a 2.4L... Lots of math to consider when it comes to that part.
Anyway, so right now I'm working on getting the car back together to get it back to the states. Any suggestions on what to do after that? I'm still not sure whether the car will be a daily driver or not, because I do have a DSM waiting for me in MD. But it has no power steering and that gets old. The RX-7 doesn't either but the effort is WAY less. So despite the lack of interior and glass, I'm actually thinking of making some panels and coming up with some sort of window setup that will allow air to enter the car.
Oh yeah, the rear-mounted radiator setup. I decided to utilize the open hole where the sunroof was. The top half of the ducting will be made with plexiglass, so that I can maintain rear visibility. The rad will actually mount slanted, inside the car, and the section between the tailights has been cut out to allow for exhausting the air. I'm just going to make some sort of sheet metal scoop to cover up the sunroof hole.
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DJpowerHaus
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