Bottom or top end?
Bottom end.. 2.4L block, 2.0L crank and Slowboy has a pretty good price for a rod/piston combo (dont even bother looking at Magnus' site.) $1063. Get rid of balance shafts FOR SURE (22,000rpm is crazy).
http://www.slowboyracing.com/more.php?id=5105&
Top end... not sure, but I'm sure it involves lots of head work. Titanium retainers.. might be one of the few applications where even I say dual valve springs are the way to go. Probably want Evo rockers (lighter, less polar moment), lighter valves, a good port job. No clue about cams. I wonder if any companies are developing a 6000-11,000rpm set of cams for this setup. FP did a cam meant for the 2.4.... so who knows.
I'm guessing the key is going to be short runner intake manifold and big long pipes on the turbo manifold... BIG (12cm2+) turbine housing. Expect boost around 5-6000rpm with HP like CRAZY from there up.
As for a transmission, I think the RX7 transmission and 4.6:1 gears would be pretty sweet behind this engine. At this point you start to get to the edge of where lots of aftermarket ignitions want to go. I think my spark setup would be fine though (4 channel, non-wasted spark with 4 coils that can definatly go over 11,000rpm on a motorcycle) Flywheels and clutches arent rated this high either.
It has been done before though. Might want to check with Slowboy Racing. I talked to someone from that shop about it over 3 years ago so I know that have 3 years experience with them minimum.
Any specs on a 11k rpm build?
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DJpowerHaus
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DJpowerHaus
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Oh yeah.. I forgot to mention about the damper. I would also consider it a must. There is one available as a bolt on for the DSM. $309 from Slowboy: http://www.slowboyracing.com/more.php?id=5809&
What twin plate do they offer that would work on a Starion pattern?
What twin plate do they offer that would work on a Starion pattern?
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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DJpowerHaus
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If you're keeping it 2.0L, you don't need the 2.4L block. The 4g63 already has a pretty rev-happy stroke and 1.7 R/S ratio. The extra 6 or 12 mm of rod length would be a bit overkill... though if the engine LIVES at 10k and above, you will likely have better engine geometry for that rev range. If you're planning to shift at 11k though, especially with the large ports of the 1g engine, I would keep the 63 block.
That's another thing important for high-revving (especially NA) engines: you have to look at the engine geometry and how it compares to the head, ports, and porting. For instance, as I alluded to, the huge 1g ports will work better with the undersquare, smaller R/S of the stock 63 bottom end. What I'd think would work much better would be the smaller 2g ports, along with the 64 block and 162mm rods. Some careful portwork and custom cams would probably fit the bill, and I'd look into some solid lifters to go with that 11k redline. I'd be wearly of using any 2.4 cams in a high-revving 2.0. The only reason I say this is because 2.4's are usually built for lower rpms than 2.0's and thus the ramp rates on the cam lobes would probably be too much for such a high-revving engine.
Also, I forgot to mention, with the smaller ports, you might want to look at making the engine more square. From careful calculation and consideration of what's out there, I figure the 4g63 (or 64) should be able to handle an 89mm bore, with sleeves (LA Sleeve makes quality sleeves for great prices for tons of engines). The oversquareness of the engine will give it better high-rpm breathing characteristics (essentially, it's much easier to fill the cylinder at higher rpms when the bore is larger than the stroke).
Anyway, I know you said you were looking into what kind of porting would be necessary, but as you can tell, it's all about the whole package. Start with your goals, decide what direction you'll take with the bottom end, and then figure out the porting needs from there.
I've been wanting to build a high-revving N/A stroker myself, but I don't have the funds or the time right now. Good luck though, and be sure to tell us your results.
That's another thing important for high-revving (especially NA) engines: you have to look at the engine geometry and how it compares to the head, ports, and porting. For instance, as I alluded to, the huge 1g ports will work better with the undersquare, smaller R/S of the stock 63 bottom end. What I'd think would work much better would be the smaller 2g ports, along with the 64 block and 162mm rods. Some careful portwork and custom cams would probably fit the bill, and I'd look into some solid lifters to go with that 11k redline. I'd be wearly of using any 2.4 cams in a high-revving 2.0. The only reason I say this is because 2.4's are usually built for lower rpms than 2.0's and thus the ramp rates on the cam lobes would probably be too much for such a high-revving engine.
Also, I forgot to mention, with the smaller ports, you might want to look at making the engine more square. From careful calculation and consideration of what's out there, I figure the 4g63 (or 64) should be able to handle an 89mm bore, with sleeves (LA Sleeve makes quality sleeves for great prices for tons of engines). The oversquareness of the engine will give it better high-rpm breathing characteristics (essentially, it's much easier to fill the cylinder at higher rpms when the bore is larger than the stroke).
Anyway, I know you said you were looking into what kind of porting would be necessary, but as you can tell, it's all about the whole package. Start with your goals, decide what direction you'll take with the bottom end, and then figure out the porting needs from there.
I've been wanting to build a high-revving N/A stroker myself, but I don't have the funds or the time right now. Good luck though, and be sure to tell us your results.
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DJpowerHaus
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DSM guys argued this point over and over for years. There were always the guys out there that said "oh a 2.4 will never be as good as the 2.0, its not a square engine, rod ratio is bad, etc etc."
Then people just did it.. and it worked... and it worked better than the 2.0. People always said that the 2.1 was useless too (becuase you cant shift at 11k rpm) until people started to do it and proved it worked with a proper transmission.
The same people would always counter with "X racer uses a 2.0 and he goes x.xx in the quarter mile" neglecting to see that the class rules restrict things like the block or crank.
Talk motor theory all you want, everything else being the same, there is no replacement for displacement... and high revs always make an engine more exciting.
Then people just did it.. and it worked... and it worked better than the 2.0. People always said that the 2.1 was useless too (becuase you cant shift at 11k rpm) until people started to do it and proved it worked with a proper transmission.
The same people would always counter with "X racer uses a 2.0 and he goes x.xx in the quarter mile" neglecting to see that the class rules restrict things like the block or crank.
Talk motor theory all you want, everything else being the same, there is no replacement for displacement... and high revs always make an engine more exciting.
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, Mike, I completely agree. I wasn't arguing for one being better than the other. I simply think that these are the types of details that need to be optimized to either particular method of power production.DJpowerHaus wrote:DSM guys argued this point over and over for years. There were always the guys out there that said "oh a 2.4 will never be as good as the 2.0, its not a square engine, rod ratio is bad, etc etc."
Obviously you can rev a stroker pretty high as Marco has shown, but you can rev that 2.1L way higher, right? Because of the shorter stroke and higher R/S ratio. Now on the head side of things, it seems a lot murkier where people have differing opinions (seems less of this stuff is actually tested or recorded with hard numbers). But what little info I've come across seems to point to the higher-revving engines with oversquare geometry or higher R/S ratios liking smaller ports and the reverse being true for the higher stroke, shorter R/S ratio, undersquare engines.
My initial comment was a little off. What I really meant to say was that I didn't think the stock 2.0 bottom end was as much a limiting factor as the head. I would think 10k rpm would be pretty doable with the stock bottom end geometry. I'd be a bit more worried about valve float, and solid lifters I would think would be necessary. I didn't mean to imply that there was no use for using the 4g64 bottom end. I mean, with an all out build, I'd totally go for that block. I guess I'm not really sure why I said what I did.
Anyway, I'd really, really love to see an N/A 2.1L tested with both the 1g and 2g heads, to see what kind of difference in power it makes.
How much power are you looking to make with the N/A setup? Do you guys think it'd be worth building an RX-7 just for an N/A 2.1L?
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DJpowerHaus
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I think a high compression (race gas) 2.1 would be fun... and in an RX7 a piston engine that revs higher than a rotary would just be a hoot.
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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carguyf545
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- Location: centralia WA.
there is plenty of potential for a high reving engine, eg: 1.6 litre crank in a 2 litre or a 1.8 litre crank in a 2 litre. for revs is would be worthwhile keeping the pistons as small and as lite as possible. the 1g head will flow enough with a very mild port job and a short runner manifold with a large penum, evo lite weight rockers and crower springs, tit' retainers and undercut valves would see 11'000 no probs. At these rpms the oil pump is on overtime so the relief valve opening should be as big as possible and a good crank scaper would be advisable or dry sump it!!
Staged injection also would be worth looking into as at these rpm's i think 1600's would loose the plot, just to share the duty of the high rpms.
I am sure that mitsu's have all the potential in the world but if it is streetable or track HP you are chasing it is very achieveable with a big bore 2.4 at 8000 rpm at 40 psi and a bloody big turbo and a good tune 800 hp is hard enough to get to the ground at these rpms and the never ending saga of a gearbox that will do what you want is easier at the lower rpms!
Staged injection also would be worth looking into as at these rpm's i think 1600's would loose the plot, just to share the duty of the high rpms.
I am sure that mitsu's have all the potential in the world but if it is streetable or track HP you are chasing it is very achieveable with a big bore 2.4 at 8000 rpm at 40 psi and a bloody big turbo and a good tune 800 hp is hard enough to get to the ground at these rpms and the never ending saga of a gearbox that will do what you want is easier at the lower rpms!