Anyone know how high i can safly twist a 3.1 with stock rods???

I havent been able to find any aftermarket rods sofar so if anyone knows where i can get some any info would be appreciated.


thx

 

bottom end is rated to 7k rpm stock by GM . . . but the topend probably isnt suited to that high of revs. i know for a fact you wont make any power up there, you will have a really hard time making any power above 5k on a stock motor, but with heads/cam/intake you should be able to make great power up there on stock rods.

there are aftermarket rods, but thats about the last part that you will need to run your motor up in the rpms.

 

Atleast if you plan to rev it that high, change the rockers out to full rollers. Change the intake, headers, and exhaust.

Not 5 min ago, I reved my 3.4 (same bottom end as 3.1 basically) to 6k. Stock rockers, modded intake, headers, exhaust.


And agree, much above 5k is just noise, not alot of power.

 

Well i am buying an s-10 to get me around till my camaro is done, it is a 2.8 manual swb. I am just toying with the idea of building the 3.1 i have in my parts car for it after the camaro is done. I just wana c how fast i can get it. I dont realy hear of many people goin fast with the lil v6.


I was planing on twisting it to 8k, i know i will have to do alot to get it to make power there but it can be done.

 

It'll be very difficult to use genI heads and make any power at 8K.

Ported large port genIII heads will be needed, along with a custom intake.

I've had my 3.2L turbo (small port top end) hybrid to 6200 RPM, where it still pulled nicely, when I get the larger port top end on it, and larger turbo I want to buzz it to about 6500 RPM.

This is in my 1985 Jimmy, ran best so far of 13.8, with a 2.07 60', and no fuel in 4th gear.

The OEM 660 rods are a froged unit out of the box, but not really beefy. I don't know of anyone that has taken a stock rod past about 6500 on a regular basis, and would recommend getting some aftermarket or modified SBC rods in there, if you plan to spend any lengthy amount of time above 7K RPM. But then again a Cam that would be capable of breathing that high, will probably have very little bottom end to it and may not be a good choice for a DD or semi-DD.

Check out www.60degreev6.com and www.domesticcrew.com

 

My 3.4 turned ~8000 rpm shifting stop and go for about 10 minutes till it locked up. It cranked back up but had a pretty good knock. It made enough power to spin 255's for like 10 yards. All useless info, but you've got more than a few chances to miss shift I guess.

...of course I'm assuming it's 8000 rpm. Needle was where the oil pressure gauge needle was supposed to be. See avatar.


-Bud

 

I am planing on building a tunnel ram for it with 2 300cfm 2 barrals on it. That should hurt my low end alittle but should breath around 8k.

What can i get gen 3 heads off of??

 

If you have a whipped 2.8, and a decent 3.1, rebuild the 3.1 and put it in place of the 2.8, for sure.

Your still going to have some problems getting it above 6k and still making power.

Gen3 heads are on the fwd version of these engines, IIRC 2000+ models, like grand prix, malabu, etc. You will also have to change the pistons then as well, and totally fab up a custom intake to make your dual carbs work on it.

 

GenIII started in '94, with the "small port" 3100, definate improvment over the genI heads, this is what I used for my build initially.
In '96 with the introduction of the 3400, a "large port" top end was introduced, and has carried right through to present.
In 2000, the 3100 received the same top end as the 3400.

 

I'm right there with ya man. Right now my motor has some kind of float at 6500. It might be ignition related, or due to manifold restrictions. But I too want to shift AND pull at 7k. I'm trying to make a ITB setup to help out.

I'm REALLY suprised you hit 8k 67 Camaro 88. What setup was that?

 

Stock 3.4 short block, 95% stock 88 MPFI everything else, and lots of hate.

It locked up after about 10 minutes of abuse. Towed it home and it cranked again... drained the oil and revved it till it locked up for good. I've got videos of the 8000rpm shifts and revving, but they are massive and I don't ahve the programs to resize anymore. I'm going to download some free version of something and see what I can do to get it online though.


-Bud

 

I just can't think ofi t but there are a few places that will host your video files for free. And they auto shrink them for web viewing.

 

Streetfire.net will, but if they think your video isnt "cool enough" they'll just delete it without telling you. They did that to a 10 sec clip of my car idling with the new cam and all, I was pretty peeved. But if it's a vid of you destroying that car, I'm sure they'll take it with open arms

 

Got it resized and hosted it...

http://www.melancholyvgs311.org/rev.mpg

Still working on the one that the engine locked it up in.

 

Not calling BS or anything, but i hear that stock tachs are off. Are you shure yours is accurate. My friends in his truck is about 1k off at top end, it says he is doin 6500 when it is only turning 5500.


I am planning on blowing the 2.8 in the truck after the 3.1 is done by adding a 200 shot to it and c how many track passes i can get. Hell maby even a 300 shot lol.

 

id guess about .25 passes off either one of those.

stock tachs are ususally off by 50-300 rpm depending on the range(its not a set rpm, ususally a %). if he jacked his rods up he was definitl;y doing over 7k rpm. if it had been a valve through a piston i could see that happening lower, but id say 8k was is a good conservative estimate for how fast his engine was revving.

 

Stock tachs are usually inaccurate as has been pointed out. I know the one in my wife's '91 RS is, as is the one in my '88 Z, this is verified by the Auto X-ray in monitor mode.

As far as building a tunnel ram to mount two carbs on it, that can be done, but it's going to take extensive head work to make the engine make power in the higher RPM ranges. And a huge cam.

Spinning an engine to high RPM is one thing, but making power up there is another.

The port size and shape on the common heads used on these MPFI engines were made to produce power in a given range with the stock MPFI intake.

And as far as the huge nitrous shot idea- the engine will probably have a backfire of nitrous before it grenades, providing it doesn't go lean from lack of fuel. Hot rod took a stock low compression 1970's 350 that maybe made 220 horse stock and somewhere around a 250 horse shot through a plate under the carburettor the engine just gagged- and had a backfire out the carb. It seems there wasn't enough volume and flow in the intake to put it into the engine.

In any case keep us posted!