Power on a Budget

[bszopi]

Granted, I started with a first year 3100, so the 3400 swap was a little easier for me. But, I picked up my 3400 (2 yr old with ~22k) for $350. It was a direct swap, done over a weekend. And I gained 15hp. You can pick up a regrind for ~$100. All the other prices are comparable to what you are talking about. So again, for under a grand, you can easily have OVER 200hp and have a more efficient and up-to-date engine.

[SappySE107]

81 2.8 has the weaker crank too. The newer motors are stronger bottom end wise, so acting like they couldn't go through what you described is a very very weak argument. There is a video on the internet of a 3.1 taking more abuse than you describe. Ill give them an equal rating for the damage you describe...thats about it.

What do those carbed 2.8s make power wise though? Sure it spins to 6000, as do the 2.8 FWD gen 2s though again, their power isn't all the hot at 6k. Its the stroke that makes it work better up there though. You can put a 2.8 crank in a 3400 block if you want.



Head porting can go well over 400, depends on what you want done. In comparison, you don't need to port gen 3 heads, as they still flow more than your heads, even with 400 bucks worth of porting. Someone should dig up the iron head flow numbers...im going off what curtis has told me.

[RacerX11]

Gen3 heads flow better stock than a set of well-ported HO iron heads. Early 2.8 HO carbed engines made ~135HP @5200 and 145ft-lb. They pulled all the way to 6k because the small displacement wasn't maxing out the heads. Put a larger engine (3.1, 3.4) under the same heads and you will be lucky to pull to 5k. With my built 3.4 (10:1CR, ported iron heads, headers, custom short-runner MPFI intake, and decent cam) would still run out of breath by 5k, even though it was making ~200HP. This is the main reason I have switched to the 3400 top-end. You admit your only reference points are 2.8's, so you have no idea how much more fun a larger/newer engine can be. I speak from experience, a modded 2.8 in an X-11 is great, but nowhere near as good as a 3.4. I also thought my 2.8 had torque. That was before I drove the 3.4

Another big benefit of the 3X00 engines is the aluminum heads, which will save ~40 pounds off the nose of the car. That will help handling considerably.

Marty

[Juglenaut]

I thought I saw someone say power on a budget....
Nothing that adds 50hp is bugetable unless you have money to blow.

[XLR8ING]

Yes, it seems I'm the only shmuck still trying to pull power out of the Gen II. Just not willing to let it go I guess.
Years ago, before anyone did the 3400 swap, I had thought about it, but now it's just commonplace, and I don't like to follow what everyone else is doing.
Now on the other hand, if I had to drop in a motor because I blew mine up, wanted some more power, and didn't want to rebuild the whole thing, then a 3400 is definately the way to go.
I almost bought an X11 last year, but don't have room for it here.
And someone please correct me if I'm wrong, but I swore I heard that the X11 could spin up to 8000 rpm? I know they should be able to rev more than a 3.1 with less stroke, but the flow rates of the iron heads would limit the revs I'd think.
If I had that car, and the cash, I'd look into porting the heads, and getting one of those intake manifolds with the individual throttle bodies that someone was advertising here.
If you really wanted to build a 2.8, get a newer (1993 or so) block, a 1989 2.8L crankshaft with the bigger bearings, some high compression pistons like the 12.5:1 pistons GM used to sell, a serious camshaft, the previously mentioned intake manifold, custom headers, ALOT of professional head work, and programmable fuel injection.
BTW, this for the most part, would be the opposite of "Power on a Budget"
Also, I've heard bad things about the Edelbrock intake. Offenhauser I hear is better.

[RacerX11]

The early X-11's had a 6500rpm redline, the later ones were 6000. The only difference was the exhaust. I can see running them to 7k (did that a couple times with mine) but anything above that you run into valve float or lifter pump-up (I refer to this as the mechanical rev limiter). With the right cam and valvetrain, you can run them higher, but I wouldn't trust the early small-journal cranks.

Marty

[Syn]

i'll suggest a hyrbid

[I-wear-pants]

is there any way to adapt the aluminum heads to a 2.8? I have a Fiero 2.8 and I dont want to have to mess with all of the re-wiring and what not involved with swaping in a 3400 even though I know its a much better engine. Any advice?

[SappySE107]

You would still have to use the intakes which means you would still have to use a DIS setup. You can spend 1500+ for the RFRE setup that is for aluminum heads but that is more for an all out racing motor.

[I-wear-pants]

why would I still have to use the DIS setup?

[SappySE107]

Well, unless you run a custom intake manifold, you won't be able to fit the distributor on there as the stock aluminum head manifolds are in the way. Maybe there is another way around it that im now aware of.

[project60degree]

What would the top max power on an n/a 3100 vs a 3400. I'm talking anything and everything done to them that means not one detail missed only on products that can be bought online or off the shelf. is there that much of a difference in the what the end results are gonna be?

[SappySE107]

Its not gonna be that great of a difference since they both take all the same stuff minus pistons. The 3100 might have an advantage on RPM cause of ligher pistons but the 3400 should make more power with less RPM. Always go for displacement in this scenario if you want a cut and dry answer.

[project60degree]

same driveline same car whos gonna have the advantage on the strip and whos gonna have it on the track?

[project60degree]

same driveline same car whos gonna have the advantage on the strip and whos gonna have it on the track?