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View Full Version : Pondering a 5sge build



Grot
04-28-2010, 04:45 AM
Really just thinking this out.

What would be needed to actually pull power out of this thing?

ive read through the 2 builds on here thousands of times, so i know about the machining.

But what compression would i need? I know higher compression is needed.

Where does the the 5sfe redline? is it a block limitation, or is it the head?

Really i guess i need to know what all i would have to do to the block to get it to utilise the GE head and the associated TVIS system. (High revs)

Hookecho
04-28-2010, 05:39 AM
the 5s redlines at 6200. i would say 2 pionts in cr would be plenty. 1 would be good enough imo. i'm not sure what kind of stock ratio you would have with a 5s short block and 3sge head. 9.5 or 10.5:1 should be good enough. you'll be able to make real power with bolt ons.

Grot
04-28-2010, 04:37 PM
Do you know what limits the 5s to 6200?

I believe the 3sge revs a little higher, and i would like to get the block to keep up with the head, im thinking all lightened internals should do it but are gonna cost a pretty penny.

Grot
04-29-2010, 02:51 AM
Anyone have any imput?

Hiko
04-29-2010, 02:55 AM
What limits the revs is supposed to be the rod bolts. There have been a few failures of them on MR2's.

IMO, if you are trying to save money, just get stock 3sgte rods, and have the crankshaft machined to fit them. If you're still worried about it after that, you could throw some ARP hardware at the problem.

Good luck and keep us updated.

Grot
04-29-2010, 02:58 AM
This, if it goes down is going to be a long build.

So im thinking of having a completely lightweight rotating assembly if it can be found.

But my quick searches have led to anything.

Anyone know off hand who will sell high-comp pistons and lightweight rods or will i have to have them custom made?

I didnt include crank because ive never heard of crank failure in a 5s or 3s

Hiko
04-29-2010, 03:14 AM
Pauter makes some rods for the 5s. There was a rebuild kit company that claimed to have high compression pistons for the 5s, though I can't remember off the top of my head.

You really should get +1mm oversize pistons from a 3sge, though. The shape of the combustion chamber does come into play with designing a proper piston, and the two chambers between F and G are VERY different. If you could find part numbers for gen 2 or 3 3sge pistons, that might work out very well.

As far as lightening the rotating assembly goes, its benefits depend on a lot of different factors. I've never looked into it specifically, but I can't imagine that power gains at the top end are going to be spectacular (and I'm betting even noticeable), and depending on how you drive, you probably don't need a fast revving engine either. You'd probably stand to benefit more from a lightweight flywheel, or simply balancing the rotating assembly than focusing on making it 30 grams lighter.

Grot
04-29-2010, 03:20 AM
Ok. I dont know anything about the rotating assembly so your imput here is helpful.

Just remembering from how my 4th gen was before i blew her up, the power really opened up 4500+ (TVIS activating)

So i would really like to build the block and head to possibly hit 7500.

I also understand cams would be needed to utilize power at the high RPM.

But as i say im just really thinking it out right now.

So that being said what is different between the 3s and the 5s that allows the extra displacement?

Is it the rods or the crank?

Hiko
04-29-2010, 05:14 AM
I might not understand the questions right, so I hope I'm not coming across as condescending with any of my answers.

Rods have no effect on displacement, only the stroke (crankshaft) and bore (pistons effectively). The rods are different lengths between the 3s and 5s with the 5s rods being larger.

Also, the bore of the 5s is 87mm and stroke is 91mm, versus 86mm for both rod and stroke in a 3s. This is where the extra displacement comes from.

You might do well to search the NA forums. Similar and useful topics have been covered there.