Don Terrill’s Speed-Talk

I have my first time on Dyno yesterday, it runs ok but do not like more than 31 total timming advance

400hp-5962rpm(tranformed from rwhp /.75) at 31º and 390hp at 35º on 95 octane gas , litle lean .92 air/fuel lambda

406hp-5490rpm (tranformed from rwhp /.75) at 31º and 395hp at 35º on sugar cane Ethanol 100% (not e85) lean .93 lambda

Is this timming ok? Title lean air/fuel ratio could be the question?

It was very warm 96º F on gas test and 103º F on ethanol test.

I was expect 34 or 36º be better.

Thanks in advance.

347 sbf, 9.8 CR (very low for ethanol), afr 185, autolite 3923 plugs 0.39gap, mallory 6al/msd pro billet dist, comp xe 274 hidraulic, performer rpm airgap, 1 5/8 hedmam headers full exsaust summit chamber muflers. Power stearing pump, water pump and alternator w/out underdrive.
chamber muflers. Power stearing pump, water pump and alternator w/out underdrive.

I would have thought that with only that comp. ratio more 5timing would have helped.
Air density must have been low( less oxyegen) to allow more timing.

Done a gas Ford 408 couple years back, much higher compression than yours though. Had Roush heads. Did not like more than 28* total timing. And ran better with 27*.

Bret

I build very similar engines alot...sbf 331 0r 347 92 octane pump gas, 10:1 with a mahle flat top and 60259 edelbrock heads. And they all top out around 31-33* timing, 430 ish hp. seems like you are in the ballpark. you can only give it what it wants

PFC1 wrote:Done a gas Ford (406 I believe) s couple years back, much higher compression than yours though. Had Roush heads. Did not like more than 28* total timing. And ran better with 27*.

Bret

How much power did it make?

You're making some pretty good power through mufflers based on
the cubes, low compression and fuel.

There is likely some extra power hiding in the exhaust/intake tuning,
and mechanical settings (cam phase, lifter settings, etc.).

Don't be upset that your engine makes more power with less timing.

Look for ways to bump the power like altering the muffler placement/
secondary lengths, carb spacers/flow plates, and things of that nature.

It was very warm 96º F on gas test and 103º F on ethanol test.

Is this your intake air temp by chance?

xstfudonniex wrote:

PFC1 wrote:Done a gas Ford (406 I believe) s couple years back, much higher compression than yours though. Had Roush heads. Did not like more than 28* total timing. And ran better with 27*.

Bret

How much power did it make?

It was just shy of 600, circle track deal using the iron Roush heads... it really needed more head on it. But it did run very well in the car.

Bret

With the motor lean it will like a little less timing.That is one of the thing I do on the dyno,lean less timing vs richer more timing.The motor in our car now likes lean less timing.

I've seen a lot of fords running the "N" heads, and it's normal for them to run timing in the 30-32 range.

CamKing wrote:I've seen a lot of fords running the "N" heads, and it's normal for them to run timing in the 30-32 range.

I just started using the N351 head. I started at 28* and am at 37*now. the reason i belive im so high is I have ressesed plug and using 110 fuel with 10.5:1.

v8_super wrote:I have my first time on Dyno yesterday, it runs ok but do not like more than 31 total timming advance

400hp-5962rpm(tranformed from rwhp /.75) at 31º and 390hp at 35º on 95 octane gas , litle lean .92 air/fuel lambda

406hp-5490rpm (tranformed from rwhp /.75) at 31º and 395hp at 35º on sugar cane Ethanol 100% (not e85) lean .93 lambda

Is this timming ok? Title lean air/fuel ratio could be the question?

It was very warm 96º F on gas test and 103º F on ethanol test.

I was expect 34 or 36º be better.

Thanks in advance.

347 sbf, 9.8 CR (very low for ethanol), afr 185, autolite 3923 plugs 0.39gap, mallory 6al/msd pro billet dist, comp xe 274 hidraulic, performer rpm airgap, 1 5/8 hedmam headers full exsaust summit chamber muflers. Power stearing pump, water pump and alternator w/out underdrive.
chamber muflers. Power stearing pump, water pump and alternator w/out underdrive.

the SBF Chamber likes a lot less BTDC timing than same cid/CR Chevy engines
27btdc to 32btdc range is mostly what i've seen .

Thank's guys
these are the dyno grafics
Ethanol:

95 octanes pump Gasoline


Feel free to make more coments about that... this will help me.

One more question, are the original afr spring (1.45" 120Lbs seated, 11/32 valves, titaniun retainers 1.7 HS rockers) ok to rev 6000+ on my xe 274H ?

PM Sent!

I think my torque courve goes down quikly above 4K.....
need some advice on it!!!!!