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Hello everyone.
So, basicly im looking to build forced induction Frankenstein motor for my SW20 MR2. I aim to make 500bhp, which is reliable and with minimal boost. Im hoping i could achieve those powerlevels under 20psi, running E85

However, this is first time im doing a turbo build. Which is why Id ask for bit of help in part selection (other tips are appreciated too ofc). Even tho Ive been lurking the forums for ages at this point, there are still some things that are still bit unclear for me.

To The point.
Block: i am planning to use is Kmods K24 shortblock, that is bored to 2.5L. This comes with Manley turbo tuffs, tougher rod and mainbearings and wiseco Pistons. I plan to go with 10.1:11 compression (too high?) Block Also comes sleeved, which i know is not required for 500whp. I think that the sleeves bring Nice headroom tho, If i ever plan to push the engine for higher hp. Is this right, or are there some cons about the sleeves?

Heres The link for The short block :

Head: Just a stock refurbished K20A2 head. I am not planning to upgrade valves or springs. I am wondering If i should to?

Exhaust manifold i am planning to Fab up My self, most likely a sidewinder of somesort. Mostly because sidewinder manifold fits great in the engine Bay of The MR2, Also it gives advantage of very short ic piping. Still im littlebit unsure about that, as im not sure about The importance of the headers length. While theres advantage of all headers running straight before collector, the headers are far from equal length. Which leads me to question, would equal length manifold be a better option? (Im looking to minimize turbo lag, i still think log type manifold compromises toi much on Power side of things, so looking for some kind of middle ground)

Intercooler : This im not sure about, the size doesnt really matter as theres lot of Space in trunk of The mr2. Tought about getting long but thin ic. As this to my understanding would Be The most efficient. Ive read that the pte ic rated for 650hp would be a great option.

Turbo : i have heard good things about precision turbos, especially on The response side of things. Apparently those arent too laggy, which is one of The most important thing for me in this section. Thats why My first contender atm is Precision 5858. Im still on Bay about If i should get The journal bearing or ceramic bearing one. Or is there a better turbo option all together?

Intake : for The intake manifold i am planning to get a skunk2 ultra street. Then pair that with some 1000cc injectors. havent decided for The throttle body size just yet.

Well thats about it, some explanations mind sound stupid, sorry about that. Ill do My best to answer questions If there are any. Thanks for the tips on advantage! Ill keep updating the build on the forums after im done with the planning phase and get The build going
 

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at 500 wHp (some 650 cranki a RWD car you need to heavily invest in a gearbox upgrade such as PPG or gear-x and a limited slip diff. A few more grands in cost, but required.
A stock k-series gearbox will shred its gear teeth off first time you floor it at this power and torque level.
Everything past some 350 Nm (crank) needs attention and past 400Nm needs upgrades.
Never mind a sensibly sprung clutch and suitable hydraulic clutch actuation.

I don’t know if you have driven a 500 wHp turbo rwd car without ESP and traction control?
This engine will be a torque and power monster.
How wide are the tyres you intend to use? Beyond some 350 wHP, 225 section UHP tyres won’t have chance in life gripping at any normal road speeds in gear 1-4 (for 500wHp) at full chat. This is unless you like lighting up the rears in 4th gear at 160 km/h with 500 wHp. -> instant spin.
You will need to use boost by gear to not get into serious drivability issues.

May I suggest you consider sticking with some 350wHP to begin with?
This would allow to keep the stock gears and would work with a completely stock K24a2 or a3. No forged nothing. This essentially cuts your conversion costs at least in half.

What is your budget?

With build engine and transmission all in, you will have to spend some 15k in hardware alone for such a conversion.
I have converted three Lotus Elise to K-series Honda engines and have a rough idea on costs.
5-6k bare conversion not touching engine or gearbox, so straight out of donor car.
15-20k rebuilding it all and fixing up everything else you spot on the car while having an empty engine bay.
At these power levels you cannot afford any worn suspension or steering racks.

Mind you this was all DIY install.

fuel pump, fuel lines, oil lines, oil cooler, engine mounts, drive shafts, new CV joints, suitable wheel hubs, wheel bearings, suspension bushings, engine block, head work, gearbox refurb plus parts, ECU, conversion loom, exhaust manifold, decent turbo charger, heat management products,
 

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If there is a k-series gearbox adapter for the E153, I believe it is called mr2 Turbo gearbox, you would save a lot money.
The k24 itself can take a lot of boost without doing much except increasing the ring gaps a little. If the 500HP are only to be used for short squirts of power, that may all it takes.
What is your intended budget?
 

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@Lotus has an excellent point of starting with a smaller power level to shake the build out. The Kseries transmission was never designed for loads of TQ. That is meaning alot of the parts in the trans were not designed for loads of stress. If you take part the shift mechanism for example, like I just did I was very surprised how tiny things are.

My shift arm and interlock needed replacement. I am also replacing the shift lever because the shaft was dug into so bad from miss shifting from the previous owner. My transmission has never seen boost. I could count how many times it was miss shifted on the shift lever.
 
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