HBZers guess my 3.1 rwhp.

[fhptom]

Well finally finished the 3.1 stroker bottom end swap on my car and will go to dyno to compare with last engine in car.

 

Old - F54 block 2.8L .040 over bore flat top pistons, N42 head stock valves with Schneider 490 lift 290 duration cam

S&K 45 mm triple carbs with 6-2-1 header 2.5" exhuast.

 

184 rwhp 177 ft-lbs torque.

 

New - F54 block 3.1L, KA 24 pistons shaved to remove lip w/relief cuts, 240 rods. Top end is still the same.

Just did a more aggressive adjustment on the cam with lash pads to get a better wipe pattern.

 

 

???? rwhp ???? ft-lbs torque.

 

Ok all you bench mechanics (and real ones) what are your estimates. Try to get within 5-10.

 

Winner gets bragging rights.....

 

Tom

Edited August 24, 2010 by fhptom

[turboHLS30]

222.35 hp and 200 ft-lbs is what I think but 200hp and 180 ft-lbs is my second guess.

[Challenger]

196 hp, 205 ft/lbs

 

So its basically just a larger bore?

[clarkspeed]

204 HP and 189 Ft-lbs. That's what my butt dyno says. Maybe more if you rev it past 5000 RPM.

 

When is dyno trip planned? I want to watch to make sure there is no cheating.

[roger280zx]

201 hp, 198 ft.lb. If the air is the same.

[JMortensen]

202, 195. My guess is 10% more power, estimated based on the 10% increase in displacement.

[turboHLS30]

204 HP and 189 Ft-lbs. That's what my butt dyno says. Maybe more if you rev it past 5000 RPM.

 

When is dyno trip planned? I want to watch to make sure there is no cheating.

 

Yea when's the trip I'd like to come see. Where are you going to dyno it at?

[thehelix112]

I'm gunna go with how I read the topic of this thread:

 

3.1rwhp and less ft-lbs.

 

Dave

[Xnke]

heh...Who did the tuning for the new bottom end? have the carbs been adjusted to match?

 

If not, i'd say about 180HP, 180TQ

 

If so, then I'd say 200HP, 200TQ, more is available with a good tune and time.

[johnc]

190 rwhp 180 ft-lbs torque.

[Gollum]

199rwhp 192 f/lbs.

[jc052685]

200rwhp 193 f/lbs.

[fhptom]

Well lets say I was not too happy after the dyno runs today.

 

HP stayed the same and torque was increased by 10. The torque and hp came on sooner and ran higher across the curve than before so that was the only good thing.

 

Quit making any power above 6K.

 

Hoping maybe the carbs might need some adjustment to compensate for the increase in displacement. The operator thought the a/f ratio showed a little air deprivation.

 

On top of that the passenger rear tire blew on the last run. I guess it was better there than on the track.

 

Tom

 

Should have went V-8 two engines ago......Throw nostalgia out the window...

Edited August 26, 2010 by fhptom

[KillerBjt]

Sounds to me like you needed to put more money into the head, thats where the real power is made. The head is probably choking that engine.

[Lazeum]

Have you played with the timing? you most likely have changed your CR & engine efficiency, timing would need some adjustment if it was not done, you might have some power to recover.

 

Regarding head design

I've been from a stock N42 head with Schneider cam to a P79 made by Braap with Rebello cam, difference was small until I bumped the timing to where it was supposed to be, difference became huge..

[SHADY280]

I agree with the above. I went from too much compression to a steetable amount and was able to bump the timing up. Difference was huge.

[fhptom]

 

Well we port matched the intake to both the head and the carbs, thanks clarkspeed, and installed a O2 bung to get better air/fuel numbers. Now it is time to get some extra jets, chokes and needles and do some real dyno tuning instead of just a base hp run.

[Leon]

[datsun723]

Sounds sexyyyyyy

[madkaw]

I am kind of where your at right now-lot's of work and not happy with the end results. I agree with the above statements that a more precise tune will get better results. I need to get a wideband also, so I am not just guessing about what's going on. I believe I have an engine that wants to breathe, but my SU's are not providing enough air to the engine, but can't prove that without the O2 sensor. Your engine sounds good-don't give up on the L6 yet, it has the way-cool factor going for it!!!