Christ, yea that's a nice setup. You were about | | <-- this close to just making it from scratch.Murray,
My water/air intercooler core is 7" long, 5.3" wide, and 2.25" thick. I started with a JR manifold, put it on an angle plate in my milling machine and cut the bottom half of it completely off, everything below the lower manifold to head bolt bosses. Then I built a new manifold using the M90 and that I/C core as guidelines. Space above the core, below the core, as well as smooth flow into the ports were also optimized, especially the #1 port which is absolutely horrible on both JR and Comptech manifolds. I machined all of these parts and then welded it all together, so the core itself has zero leakage. 100% of the discharge air HAS to flow through it. I machined the end tanks so the water flows through the I/C core twice, and sealed the bottom plate to water tubes using O-rings. All of this took about 60 hours. It fits with the stock firewall in both the S1 and S2 Elise/Exige, just barely but it fits.
You have access to WAYYY more resources than I could ever imagine. I know you are primarily into prototype stuff, but there seems to be a decent market for an off-the-shelf higher horsepower positive displacement blower for the K series.
TVS 1320 (or even 1900), with a nice manifold and a cooler to match. Just saying
Interesting... I still have the infrastructure for the stock oil coolers in the front and could put them in the loop but for now I think I am just going to use a heat exchanger setup developed by BOE which runs in the back. Has some ducting off the scoop and a few nice fans as well... Not ideal, but then again my little drop in IC core in the JR access panel is likely the weakest link anyways.In the Elise I use the stock up-front oil coolers as my heat exchangers. Derek followed my lead and did the same thing. Its not ideal because they're essentially cheap English oil coolers and rather small, but Lotus was having trouble cooling the 2ZZ motor with just water so they added the oil coolers to help with that problem rather than making a bigger radiator. At some point I'll have Ron Davis make a pair of bigger heat exchangers that are actually made for water rather than oil, but when I was using the M62 S/C K20A setup in the Elise they worked pretty well. Only 325 HP (stock motor with 9 psi), but the air into the engine never got over 106 F and that was on a LONG WFO run out in the desert at 90 F ambient.
Yea what is interesting is that I don't expect near 16psi. I actually think it will be in the mid/high 13s based on what I saw with my last pulley (3.5"). Not sure what to make about that. I do have more displacement, but your K23 I'm sure outflows my stock K24A2 based on VE (your built head + cams I'm sure outweighs my ~50cc more displacement). I do have an aftermarket M90 which may trade off blower VE for more overall flow at high blower speeds?!With your 5.98/3.25 setup you're at 84% overdrive, so just a little higher than the 81% I ran to get 16.5 psi. The E-85 helps in your situation. You just don't have the rpm potential I have because of the 'tractor motor' 99mm stroke. That's one of the biggest reasons I built my "K23". Its 90mm x 90.7mm (2,308cc) and has a 1.75:1 rod/stroke ratio. No matter what it'll always make more power than a K24 even though its 46cc smaller. The only reason Honda used a 99mm stroke in the K24 was to get the displacment over 2,350cc so they could call it a 2.4 liter motor. Pure advertising, not engineering.
I'd imagine Derek has told you how much he dislikes the K24 in his Elise because it can't rev. Eventually he'll get around to building his 'real' motor, which will be 89 x 90.7 and R1900 supercharged. Then he'll be a really happy camper!
Take care and have fun,
On the topic of engines. I agree the K23 setup you have is basically the ideal engine, and I also dislike the lack of RPM that I have with the K24A2. I started with a built N/A K24 and my header was designed around that. When my engine blew (had terrible luck with people building my engine), I just went with an OEM motor and the K24 made more sense since I didn't have to remake my header.... hence me running a (mostly stock) K24A2. I would trade off torque for more RPM any day of the week, but at the same time I can't complain much. I will be making somewhere in the high 300s at the wheels with a (literally) $1500 engine from a junkyard. I can't honestly say the chassis needs more. The more pressing issues for me would be a transmission that can take the abuse (along with different ratios), and more importantly brakes/aero.
P.S. I am more of an electronics expert like Derek and am not a mechanical guy so much. What exactly is done in the case of the K23? I am assuming it involves taking a K20 (or is it K24) block, overbore + sleeve, AP2 crankshaft, and custom rods/pistons? Is the block or crankshaft modified to make it work? I know the bore spacing is the same however I thought I remember hearing of different bearing sizes between the F and K.