3.0 Guru's

[3rdGen3.0]

Several Questions...

Anyone have a stock dyno plot for the 3.0L?

Where to get oversized valves (will the 3si versions work?)?

Approx. price for a set of custom forged pistons?

[Ondonti]

This isnt stock, you can see the mods that were done in the dynosheet.

As far as oversize valves, in the next month or so I might have some made so we will see then. Custom valves from a valve company are expensive, but you can probably have some made at a good machine shop for pretty cheap.

[93sundance]

Heres an 88 3.0L auto caravan on the dyno. I believe it is stock. If not it was damn close to stock at the time.

http://www.robskorner.org/88caravan/Dynorun.html

[Boogieman142]

wow,those numbers look alittle low, espicially for torque, must have been the 3 spd.

[93sundance]

Quote:

Originally Posted by Boogieman142 wow,those numbers look alittle low, espicially for torque, must have been the 3 spd.

ACtually those are pretty good numbers for WHP. Especially on an old 88 motor. I believe it was the 3 speed (A670)

[mwinkle353]

Hmmmm. Lemme see here. The factory motor made 141hp at the crank. Take into effect that the caravan had a 3 speed auto, that would be about 20% average powertrain losses. So, theoretically, we should see about 113hp at the wheels. If it was a 5 speed manual, then we'd say only 15% powertrain losses on the average. And that number would be around 120hp. So for that motor to run low to mid 120's is accurate for stock on the rollers.

[93sundance]

EXACTLY! So that engine DEFINETLY had over 141 hp at the crank with all those miles on it. I been wondering for a while now how underrated the 3.0L is. I wouldnt be surprised if alot of them have 150+ hp at the crank stock. I wonder if i have 200 yet. What do you think Wink? Brent thinks I have around 193 at the wheels. that would cool. I am planning on visiting a dyno after i install the diamante cams and of course replace the tranny. Right now i have 0 WHP hehehe

Quote:

Originally Posted by mwinkle353 Hmmmm. Lemme see here. The factory motor made 141hp at the crank. Take into effect that the caravan had a 3 speed auto, that would be about 20% average powertrain losses. So, theoretically, we should see about 113hp at the wheels. If it was a 5 speed manual, then we'd say only 15% powertrain losses on the average. And that number would be around 120hp. So for that motor to run low to mid 120's is accurate for stock on the rollers.

[mwinkle353]

I'd say you're close to that mark. Given your times and esitmated weight.

[Ondonti]

I figure my sohc was pushing around 183whp with my weight and trap speeds.

I think some people do really underestimate the power increase when you have all the bolt ons, big exhaust, 58mm tb, and a heavily ported intake manifold.

I think it also makes sense that the 3.0L is a bit underrated from what Ive seen.

From Robs stock #'s I'd guess that old 88 motor was making 154whp crank with 123.7 FWHP on the dyno. I figured my pretty well modified 4 speed auto was making 145whp or 178 crank hp. Going up the the 5 speed with aluminum flywheel, ported plenum, 58mm tb, UPD and real 3" exhaust seems to have freed up another 38whp.

I think those trap speed based WHP #'s are very accurate, because the trap speed really isnt effected by our gobs of down low torque. My current 3.0 engine that I got from a 120k mile caravan that was not maintained, will slightly outrun a v6 5 speed SHO from a roll in any gear. I Most of my runs I did in 4th gear while he was in 3rd gear, and I would catch up at the top of 4th gear. If we both went from 3rd gear then he wouldnt get the jump on me. Guy who owns that SHO is on td.com (bansheenut)

[93sundance]

My stock spirit definetly isnt slow. I burried the needle at 120mph in no time.

[roguetrip]

Quote:

Originally Posted by 93sundance My stock spirit definetly isnt slow. I burried the needle at 120mph in no time.

Must have a healthy 3.0, my takes abit after hitting 110

[Ondonti]

Quote:

Originally Posted by roguetrip Must have a healthy 3.0, my takes abit after hitting 110

Doesnt yours have a lot of hard miles?

[93sundance]

My stock duster topped out at about 110 after keeping it floored for maybe 5 miles. It just didnt want to go faster. IT had a tired 3.0L though. I'd say the spirit's 3.0L is pretty damn healthy for 163k miles. I can get the car up to 120 easily, even with my 300 lbs friend, tool box, 3 ton floor jack, and full interior in the car.

[93sundance]

I think the 3 speed trans has something to do with it too. When the A604 shifts to 4th its slow after that. When I am over 100 in 3rd gear with the A670, it seems to be right in the power band. My car would suck at a race at a 75-80 mph roll, but once the RPM gets close to 4,000 in 3rd it starts pulling hard.

[roguetrip]

Quote:

Originally Posted by Ondonti Doesnt yours have a lot of hard miles?

Yeah i do rev out the engine alot, about 148k or so on it now, usually do maintanance regularly since i got it at 90k, i do think moving from the A604 to the A543 it does get to 120mph faster, but it just takes a bit after i hit 110. Although there have been times where it hits 120mph (or the govener) in no time at all but i think it has more to do with the conditions outside.

As far as a race goes, its usually good unless its at a roll of 70-90mph already

But i'm loosing alot of power right now cause i need some solid motor mounts, i've got a solid bubble strut and a new front motor mount (advanced auto) and the engine still will rock like crazy when punching it!

To the OP, i don't think the SOHC valves are any larger in the 3S's, i believe most of the extra power was the intake cause it was long runners that could cool the air down alot, i'm not positive but also think it had a bump in compression. Also chrysler minivans around 95 also got a bump to 9.5:1 which i think added 15hp or so. Also if you going to go forged pistons, then you would want beefier crank which i know the TT/VR4 had forged cranks, could save cost instead of cryo'ing your n/a crank or getting a custom one.