paddy351

hi guysi am going to book my car in for a dyno tune. i would like a few hints to help ie timming jetting . I understand every engine is different but has anyone run a similar setup.

351 clevo std bore
2v heads ported 4v valves 10.5 comp
acl race series pistons
F238 solid cam 3000 6500
holley 750dp jets 71 80,s---11.6 afr
wieand excel manifold
msd dissy digital 6 msd
fuel 100 avgas


i got 194 kw, 260 rwhp- 594nm
what should i pull from this combo

geos sho

what is the metric to us conversion as i am lazy!!!

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my need is speed

paddy351

260 rwhp and 477 foot pounds of torque

xdclevo

11.6 seems rich.
I try to get about 12.8-13 afr.
Slightly richer if you are flogging it or racing it regularly.

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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.

northiam

477 ft pds of torque!! You have a weapon, congrats. You have the most powerful 351 I know!

paddy351

i did the conversion and it worked out at 437 ft/lb foot pounds not 477ft/lb and i have seen many clevo,s with 450 + ft/lb torque, that is what they are known for.

xdclevo

We all know a chassis dyno aint going to calculate power correctly, let a lone torque, but fun to have a chat about.

My fresh 351c in 2005 did 279 rwhp, and 896 lb foot. Go figure.
In 2002 with small hyd cam, it did 215 rwhp and 700+ lb foot.

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10.70 @ 125.00 on the black fun top
408 Cube Cleveland.

paddy351

yes but 437 or 477 is able of a 351 clevo on a engine dyno, not rollers

TruBlu351

It should be putting out more rwhp than that. My stock 2V's with small hyd cam did that. But Dyno's can vary.

I'm going to guess that you're running that whole setup thru a single pea shooter exhaust?

Jetting has been touched on. Go a tad smaller and lean it up a bit. Your engine may not need the higher octane avgas......again, something to try on the dyno/track. 10.5 comp isn't over the top and shouldn't ping on 98 octane pump fuel. Higher octane is used with high comp motors that require the timing be knocked back if using lower octane fuel....due to pinging. If your engine can run great on 98 fuel.....anything greater won't necessarily increase power.

With avgas you'd need smaller jets compared to a lower octane fuel to get the ideal AFR.

Just be aware that avgas contains low amounts of lead and can result in huge fines if used on the street. It has a distinct smell/colour and I beleive traffic cops can test for lead in the exhaust.....some sort of probe thingy.

Timing is engine dependant too. Just a matter of playing with different settings on the dyno. I'd guess somewhere in the mid 30's for total timing. Just go up and down a few degrees until you find the peak and where it starts dipping again.

800ft/lb torque is Mack truck territory!! Just for info, my 393 stroker made 511 ft/lbs of tq on a trusted engine dyno.

Power and Torque have a related equation which is:

TQ = (HP x 5252)/rpm

........although I can't always get things to add up perfectly......just ball park gross checking.

Sometimes a dyno will spit out TRACTIVE EFFORT as the torque result........ which must not be confused with the actual torque figure which will be Foot Pounds or Newton Metres.

Tractive Effort is simply a value of POUNDS (lbs) or NEWTONS (N).

Here's the related equation....

Torque = (Tractive Effort x Tyre Radius)/Diff Ratio

eg: my old 351 made 1250 lbs of TE. I had 25" tyres or 1.05ft radius with 4.11 diff gears......which all spews out as 319ft/lbs of rear wheel torque.

IF the dyno guy plugged in 2.7 gears then it would say I had 486ft/lbs of torque.

But regardless of the dyno calibration....just aim for the peak numbers and you'll be right.

..........upper-cut for rambling

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XE Falcon
393 Tremec TKO 9"

paddy351

Thats cool trueblue, I have a log book for avgas with my club so "all good" I did a power run on a dyno and it lost power at 4700 then i run avgas and peak power was 6300 "normal" Timming would be an issue there as well. I read that the chamber shape oF the older heads can cause pinging at lower compresion. I run 4 into 1,s with a single 3 inch. Dyno tune will sort out the donk. Cheers.