dyno advice

[Boiler Ben]

I'm getting ready to have my 390 dyno tested before putting into my Factory Five Cobra.  I'm looking for any advice on RPM like low to high RPM for testing and what a safe redline would be.  I won't be racing this, just something fun to drive.

It's a 390 bored 0.030" over with stock crank and rods.  It has a hydraulic roller cam and Edelbrock Performer RPM intake and heads.  The heads came complete with whatever springs they use for hydraulic rollers.  I have roller rockers with end stands from Precision Oil Pumps and I put restrictors in the heads.  I have a Holley Sniper sitting on a 1/4" spacer and I'm using a K&N E-1960 air filter element.  This is the Ford long oval type that is 1.81" tall.  It may be a little restrictive but better than the paper element.  I won't have a lot of hood clearance.

I think the Sniper has a rev limiter function and just wondering what to set that to.  And what to expect for the test to get good results but not push it too far.

[blykins]

Will depend on the cam on how high you'll want to turn it.

[Boiler Ben]

The cam is 224 intake duration at 0.050”.  It has LSA of 114 and intake centerline measured at 109.

[My427stang]

If you run the Sniper rev limiter at all, run it way above where you want to test, like 6200+

It likely doesn't even need to be functional until after the dyno, but if you were afraid of a runaway pull, you can but you don't want to accidentally be troubleshooting a high rpm misfire when it's your rev limiter.

I'd pull 4500, then 5500, check timing, a/f, etc, along the way and make the big boy pulls based on where peaks are, but my guess is 6000 will show when the curve drops.

A couple Sniper lessons:  Keep the O2 sensor wiring FAR away from any plug, coil wire, or coil.  Be sure to check your offset of timing after you get it running (assuming you are running a Hyperspark or DualSync), and laptop monitoring / tuning gives you MUCH more control that the hand held. Also, use street/strip cam with the handheld, not mild.  Some guys use a vacuum reference for cam choice, don't, it  is completely in the street/strip range and the cam choice brings later and safer tuning in

Last comment: Not a fan of out of the box Edelbrock springs, they tend to be light and have seen a couple different variants.  I'd recommend at least checking a single and seeing the what open/closed pressure is.  It'd be a shame if it wouldn't pull to the top

[FrozenMerc]

Much will depend on the skill of the dyno operator and the particular dyno setup, but if you are not using it for racing, don't focus on the wide open throttle pulls as much, instead focus on simulating actual driving conditions.  Part throttle transitions, cruising AFR and timing, optimizing area under the curve and not peak numbers, etc. 

Dyno time is valuable, use it to tune and dial the motor in to how it is going to be used in the field as best as you can.  Very rarely do we only drive our street cars in 3,000 to 6,000 rpm WOT bursts.  Especially lightweight fiberglass replica's that may have more engine than suspension. 

[hbstang]

the sniper you have will do most of the tuning by itself,and for your 390,i would spend the money on other stuff instead of a dyno,like better valve springs etc.just ,my ,02 cents here.

[blykins]

To me, the dyno is invaluable, and I think it's money well spent.  So many things that will be better to catch on a dyno cart than after you get it shoehorned down in a vehicle. 

[blykins]

I'm getting ready to have my 390 dyno tested before putting into my Factory Five Cobra.  I'm looking for any advice on RPM like low to high RPM for testing and what a safe redline would be.  I won't be racing this, just something fun to drive.

It's a 390 bored 0.030" over with stock crank and rods.  It has a hydraulic roller cam and Edelbrock Performer RPM intake and heads.  The heads came complete with whatever springs they use for hydraulic rollers.  I have roller rockers with end stands from Precision Oil Pumps and I put restrictors in the heads.  I have a Holley Sniper sitting on a 1/4" spacer and I'm using a K&N E-1960 air filter element.  This is the Ford long oval type that is 1.81" tall.  It may be a little restrictive but better than the paper element.  I won't have a lot of hood clearance.

I think the Sniper has a rev limiter function and just wondering what to set that to.  And what to expect for the test to get good results but not push it too far.

I think a 3000-6000 rpm pull would let you know what's going on.   I've never been a fan of loading an engine hard way down low. 

Just keep an ear open for valve float.  The Edelbrock valve springs will most likely be light for a 3/8" valve engine with a hydraulic roller, especially if the hydraulic roller is a shelf cam.

[Boiler Ben]

Thank you for each of the comments.  I feel better prepared now and the dyno shop does seem very knowledgeable.  I wanted to make sure this thing works properly before dropping it in the chassis and mounting the body.  I did think about "more engine than suspension" as I was choosing everything.  It won't be as fun if I can't control it.  So I used a lower compression ratio and will sacrifice some power for the ability to use 87 octane.  So I am curious to see how it all works out.  I'll post results when it's done.