Guest TurboSedan Posted June 26, 2003 Report Share Posted June 26, 2003 are there any advantages for the 2.8 over the 3.1? i mean, does it rev faster or higher? could it be a better candidate for a turbo? or does the 3.1's extra low end torque outweigh any 2.8 advantages? it's sorta the same story with the turbo dodge 2.2/2.5. the 2.2 'T2' revs higher and faster, has a bigger turbo, an intercooler, and a forged crank. the 2.5 on the other hand has a cast crank, much smaller mitsu turbo that spools quickly, more torque, NO intercooler, but doesn't rev like the 2.2 will. the 2.2 'T2' has about 30hp over the 2.5 'T1'. heck Chrysler wouldn't even put a 2.2 'T2' together with an automatic because it was just too powerful. any insight? joshua Quote Link to comment Share on other sites More sharing options...
GnatGoSplat Posted June 26, 2003 Report Share Posted June 26, 2003 I don't think the 2.8L revs higher, because it's pretty much dead over 4000rpm. The only thing that happens over 4000rpm is it gets noisier and noisier. It does rev quickly, however. I don't know that it revs quicker than an NA 3.1L, I don't own an NA 3.1L car so I can't really compare. Quote Link to comment Share on other sites More sharing options...
brian89gp Posted June 26, 2003 Report Share Posted June 26, 2003 Technically a shorter stroke is better for high rpm but seeing as the 2.8/3.1 is a relatively low rpm motor I don't know if there would be signifigant gains or not. The 3.1 and 3.4 crank have the same stroke and the 3.4 is good for 8000rpm. For boost I hear the 2.8 crank is slightly better because the dwell is longer, but you have to loose .3L to get that. There are fiero owners continually talking about putting a 2.8 crank in the 3.4 so that they can regularly see 9-10k rpm. For me I'd say unless you are planning on converting the 3.1 into a 7k+ motor that the 2.8 crank is not worth the trouble. Quote Link to comment Share on other sites More sharing options...
dbtk2 Posted June 27, 2003 Report Share Posted June 27, 2003 There are fiero owners continually talking about putting a 2.8 crank in the 3.4 so that they can regularly see 9-10k rpm. Your talking about the 3.4 DOHC engine right? Because the pushrod 3400 will never be able to safely run that fast. For me I'd say unless you are planning on converting the 3.1 into a 7k+ motor that the 2.8 crank is not worth the trouble. Even if you are going to convert the 3.1 to rev at 7k you don't need the 2.8 crank. The 3.1 crank is fine. Anyone crazy enough to regularly rev a 3.1 pushrod to over 7k is going to have to make a lot of other things stronger first, and it isn't easy to do. People spend a lot of money on L67's to be able to safely rev them to 7k and the L67 is built to rev higher in the first place. My $.02 deposited. Quote Link to comment Share on other sites More sharing options...
phantomFE3 Posted June 27, 2003 Report Share Posted June 27, 2003 i dont know if this will help any, back in the day when they made 3 wheelers, honda made a 200s and a 185s, the 200 and the 185 shared the same bore, except the 200 has a longer crank. the 185's did rev alot faster and plus they still had pretty good torque, but the point being, the 185's were alot faster than the 200's, by a lot!!! i have a honda 185s that is really built up, ok, not really, but it has a high lift cam, and racing exhaust, those are about the only power adders, the only race that i have lost with it was against a new yamaha warrior!!! it pulls wheelies all through 4th gear, 5th gear doesnt have enough power. SO YA ANYWAYS that is what i have to say, i know 3 wheeler engines are a hell of alot different than car engines, but maybe with alot heavier vehicle you need the extra torque? but like the saying goes: theres no replacement for displacement!!! Quote Link to comment Share on other sites More sharing options...
brian89gp Posted June 27, 2003 Report Share Posted June 27, 2003 Your talking about the 3.4 DOHC engine right? Because the pushrod 3400 will never be able to safely run that fast. Even if you are going to convert the 3.1 to rev at 7k you don't need the 2.8 crank. The 3.1 crank is fine. Anyone crazy enough to regularly rev a 3.1 pushrod to over 7k is going to have to make a lot of other things stronger first, and it isn't easy to do. Yea, the 3.4 is the DOHC, the 3400 is the 3400 The 3.1 can handle 7k with some work on the valvtrain the problem is getting it to make usable power up there. Back in the carburated days they had 2.8's i think with 300hp, 12:1 CR, and 6-7k with useable power. Quote Link to comment Share on other sites More sharing options...
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