Stroking the wrong way

[Plechtan]

The Bonneville Comanche currently has a 4" stroke 7CW crank, an Hesco aluminum head, and makes about 450 HP naturally aspirated. It's not enough!! We need more!! Looks like the only way to get it is to get more air through the head, and turn higher RPMs Of course when you turn 7K or so with a 4" stroke motor, your piston speeds go out of sight. SO to get more air into the motor, we have decided to use a turbo. We could just keep the engine speed down like they did with the JP Magazine Extreme inline II, But HP at higher speeds mean less torque which would be easier on the drive-line.

Low and behold if Christmas came in February this year. Hesco use to have a 3.0L Jeep inline 6 they ran in the stadium trucks. It was a 258 sleeved down to 3.5" bore and it used a 3" stroke billet crank. See Below;

100_1821.JPG

100_1822.JPG

The crank will take 2" Chevy rods. The idea right now is to stick with the 4" bore block, go to 3" stroke and boost the piss out of it

[NorCalChris]

sounds like its going to be alot of work. Any ideas on what rpm range you will be operating in?

[Plechtan]

7,500- 8,000

[Alex22]

Nice looking parts there, does Hesco happen to have a set of rods around for that as well or are you going for a set of custom rods?

~Alex

Edit... I re-read the OP and the answer was in there.

[Plechtan]

I did also get rods and pistons, the rods are SBC (forged)with a 2" journal. they are 6.2" long (approx) My current rods are also 6.2" but billet H beams. The BE width of my rods is 1.060. the crank is designed to take a chevy rod (.940? BE width) So it looks like my best bet is to get custom 6.7" rods made, and keep my current pistons. with the reduced stroke the cr should drop to about 10:1 (4" bore, 3" stroke, zero deck, .043 gasket, 57cc chamber.)

It may be a better to put the piston down in the hole a little, maybe have a .050 quench I heard turbo's like that, but Iam not a turbo expert. maybe somebody can chime in.

[gradon]

Believe it or not, I've heard of people having the piston come out of the cylinder a bit(as well as o-ringing) for boosted applications. Apparently it reduces the chance that the HG will blow out. I don't know what type of gas you're going to be using, but most people shoot for a 8-9:1 SCR pre-boost when using premium gas. I say go for it. Let me know if you're looking to unload the DCOE/redline system--I'll put it to good use.

[Plechtan]

We will be using 118 octane racing fuel. The Ecotec motors run 10:1 from the factory. for a 2L 4 cylinder engine, they are able to get 1500 hp from them. The land speed version is only 750 hp.

The intake setup is not Redline, it is a clifford intake with a Extrudabody ITB setup. With the turbo I will be ditching it in favor of a traditional intake. I will be using a Clifford, but machining it for injectors and probably going with a 95mm Throttle body.

I'm not sure i want to sell the itb setup yet.