4g64 destroked to 2.1L

[Mirage2LTurbo]

I've done alittle bit of reading up on this, but can't find anyone that's done it. I'm revving to 9-9500 right now, what are the pistons speeds and rs ratio of a 4g63? Would there be any advantage to go to this destroked 4g64 setup, or is my powerband not going to last past where I'm revving now? 272's, FRH smim, 1mm+ valves, head work, T67, etc.

 

[Kevin Jewer]

I think just as important as maybe bumping up the rpm range a little bit, is you will be reducing stress at the rpm level you are at now. And you get a little more displacement as a side effect, about 5%. But thats all I can offer considering my lack of personal experience with a 2.1.

 

[silverbulletAWD]

4G63 w/150mm rod = 1.70:1
4GCS w/162mm rod = 1.84:1

Mean Piston Speed @ 9000 rpm = 86.6 ft/sec.

-all assuming an 88mm stroke-

I like this idea personally. I've never looked into what they're actually doing but I can only assume they're using a 2.0 crank, stroker pistons and 162mm rods in a 4GCS block. Most guys’ seem to think it's worthless to try and shift a DSM above 9k anyways so they would rather pick up the displacement instead. If you look at the 2.3-4L motors rr's you'll see all the way down to a 1.50:1. I was always told to try avoiding ever going below that exact number but more and more experts seem to be saying that rr's are now irrelevant. Even the street bike makers are shortening the decks on these 15k rpm bike's and picking up horsepower so who am I to say. Their mission is reducing reciprocating mass and apparently top dwell, piston speed and side loading are all inherent problems that have been dealt with. Now I've heard of some solutions to reduce side loading that could and has been built into some pistons lately but I'm still not convinced that a long super-light rod won't, when all things are considered, give us a lighter mass than an ultra fast piston speed short rod. And that’s not even considering top dwell in the equation. I mean, look at some of the rod ratio's F1 has run. Shoot those are some of the highest HP per cu. engines in the world. Although they do have some longevity issues to deal with that we don't.

I plan to go this route some day when I decide to win the lottery and convert my car to methanol at the same time. By lottery I mean dog box to make the most of things. Oh, and titanium rods too. For now, my next short block will have 88mm stroke, 156mm rods and 6mm up pistons originally intended for strokers. This will at least get me up to 1.77:1 which I think should be good for something especially considering the pistons are lighter and the R's could maybe go a bit higher and I need new rods and pistons anyways. (getting nervous about stockers limitations.)

As far as your set up goes I would assume you have also spent some money on your valve springs and retainers and with that being done the next limitation might be the cams but I don't think power would just simply drop off. Might not be a bad idea to add some oil capacity either.

Andy

 

[rca90gsx]

Or you can just use a standard 2.4 piston, 2.0 crank of course and a 156mm rod. Thats the easiest route, although still pricey compared to a standard 2.0 build. You also increase piston dwell time, the engine will breathe better all around though...

Just some thoughts..
Richie

 

[yoshimitsuspeed]

I would love to see some numbers, like horse power, torque, powerband, and red line. I would almost do this just for the sound but there would have to be some practicality to it. What could be done about the tranny? I guess a dogbox would really be the way around it but is there any way a stock tranny could work?
I think it would be awsome if you pulled up to some ricer who revs his engine at a stop light. If you could just rev up to 14,000 or something it sure would be fun to see their face. :laugh:

 

[Black94TSI]

There are advantages and disadvantages to an inreased R/S ratio, so don't think a massive rod and a short stroke is the be all, end all to your motors problems. A motor with a small rod/stroke ratio can still last an incredibly long time, and make lots of power. A motor with a large rod/stroke ratio can fall apart in 10 thousand miles, and make squat for power. Lots of positives and negatives are created by increasing the rod length and decreasing the stroke, IE a longer rod creates more piston dwell time at TDC, promoting detonation. I go by the rule that RPM RPM's. RPM's Ruin Peoples Motors. I would do the longer rod with the 100MM stroke crank in the 4G64 block. Keep the revs down, torque up, make a fun car that should last a long time on the street.

 

[jmakado]

magnus has done it and i think marco runs a 2.1 in the drag car....they of course run the magnus dogbox though....i think you would have to run a dogbox to take advantage of the extra revs a 2.1 would give you. most of the fastest dsm'ers (shep, rau, buschur) still seem to run the 2.0 though. if i was building an all out race car i think that 2.1 and a dogbox would be sweeeet!

 

[jshepherd]

The major problem with the 2.1 is you are very limited in head gasket availability. Shifting is not even a concern anymore. I have been shifting at 10k or close to it all year easily.

 

[silverbulletAWD]

The major problem with the 2.1 is you are very limited in head gasket availability. Shifting is not even a concern anymore. I have been shifting at 10k or close to it all year easily.

Are you still running a 2.0 for real? Stock length rods and pin locations?

 

[gaddis]

John are you shifting at 10k with the Shep Racing race transmission as listed on your site, or are there additional modifications that aren't for sale?

 

[Kevin Jewer]

Taken from http://www.shepracing.com/sr_serv1.html



* SHEPHERD RACING RACE TRANSMISSION *
(same one used in our race Talon)

 

[Mirage2LTurbo]

Mr. Shepherd,

Do you see a practical reason to switch from a 2.0 setup to a destroked 2.4? Can you offer any specifics on the setup you are running (as far as the block/crank goes)?

-Colin

 

[jshepherd]

Yes I am running the same trans I sell and The same ones that I build for Sean Glazar and Daryl Hudson etc.

I see no reason to switch to a 2.1 unless we have maxed out the 2.0 and as of now that has still not happened. I am still running a 2.0 with stock length rods etc.

 

[Stapl3]

A 2.1 destroked motor would be killer for autox and highway runs. That's about it.