Kevin_White19

I'm looking at internals for a 2.4L build (90mm X 94mm BxS). I'm not planning on going above 600hp and the build is more for all around performance rather than being the best at any one thing. The reason I'm going 2.4L as apposed to big turbo standard bore is is for low end torque, and quick spool while retaining solid rpm cababilities with good top end.

To get to my question: what is the lightest internals setup for the 2.4L build that still allows for 600hp and a nominal 9000rpm redline? Are H-beams a possibility or are the speeds and stresses associated with this dangerous? Especially when going close to 10.0:1 compression ratio or up to 34lbs boost.

Thanks,
Kevin

Kevin_White19

I'm planning on going with a 6262 ball bearing turbo or something similar in size if that helps. Built head of course with full AMS piping and Akrapovic exhaust yada yada yada

LetsGetThisDone

iTrader: (1)

94mm stroke shouldn't be revved past 8k in a 4b11. The rod ratio is pretty bad. If you want to rev to 9k, keep the stock crank, bore it to 90mm if you want. I also wouldn't use a Gen1 6262. Either step up to a Gen2 6266, or use a Gen2 6062 (smaller compressor, but more power capable than Gen1 6262).

Kevin_White19

I like the 6062 suggestion I'll look into that. The 7 blades seem to work much better than 6 blade design. In terms of rpm limit I assume that because of the con-rod ration, it becomes an issue of cylindrical misalignment between piston and cylinder. I can't assume I'd be getting much power increase between 8k-9k unless I do some serious headwork with the cams. Plus if I were to do the 2.2L bored more tailored for rpm, It would make sense to go bigger turbo so it has high end pumping efficiency. Doing so would end the quick spool goal because a bigger turbo makes more sense with a higher revving engine and a higher revving engine = smaller stroke therefore = more lag. Catch 22s suck. I'm currently under the impression that the 2.4L would be the best engine to put in the car if I wanted it to perform "well" in ant motorsport event but not be the best in any. I could be wrong but I'd love to hear more of what you all have to say.

-Kevin

LetsGetThisDone

iTrader: (1)

I would not run a 94mm stroked 4b11 for motorsport. The rod ratio sucks. Just like I wouldn't run a 100mm 4g63. Bigger bore is still more displacement and will help spool up. The pte 5858 spools at 4500 on the X, and makes power to 8-8500. The Gen2 6062 would probably spool ~400-500rpm later, and would make power to 9k most likely.


If you want to extract as much as possible out of your turbo setup, and maintain best reliability, a ported head and cams in a must on the 4b11. Just with head porting, English Racing saw a 200* reduction in EGT in their testing with the 4b11.

Kevin_White19

Definitely taking your advice and doing a head build.. probably MAP since they've been so helpful with all my questions and all the big companies seem to port similarly. As far as the engine build I'm pretty set on going larger displacement but I'll take everyone's advice and just bore it. My question though is why nobody makes a 90mm crank to make a square 2.3L 4B11 motor?

LetsGetThisDone

iTrader: (1)

I wouldn't get anything from MAP. I've heard from reputable sources their head literally makes less power than stock. If you want a good head, send it to English Racing, or leave it stock and put cams/springs/retainers in it.

317Speedworks

4 Piston Racing if you want to ship the head to Southern Indiana. They do phenomenal work.

VeebeeIX

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