[Speargun]

I have my first tuning session scheduled for next Thursday on a chassis dyno. What should I do to prep or take with me?

I'll be taking my laptop to tune the FiTech EFI
One step colder plugs. Just installed a set of NGK BKR5E-11 @ .044 last week & have a new set of BKR6E. I had a set of BKR7E, but they were too cold.
Intakes? I'm currently running a Holley Street Dominator, but have a Victor & a Warrior and several spacers.
Basic hand tools.

I'm going to try to get around to swapping out the MSD 6AL for one with timing control this weekend so timing changes are easier.

My combo is:
455 +.060 (469cid)
Fitech 1200
Un-ported E-heads 72cc
10.25:1 scr, 8.7:1 dcr
Hyd roller 583/561, 236/248 @ .050, 106 cl, 110 ls
Doug's headers 1 7/8" primaries. 3" X Pypes to rear quarter exit

Desktop Dyno (version 4.20) says this engine should be somewhere between 550 - 600 hp & tq @ the flywheel, but playing around with different settings in the program that should increase hp & tq doesn't give expected results, so my confidence in it's results isn't very high. For example, adding better flowing heads actually reduces hp & tq.

[Steve C.]

Not for your session but curious, is the HSD intake port matched to the heads ?


.

[Speargun]

Originally Posted by Steve C.

Not for your session but curious, is the HSD intake port matched to the heads ?
.

It's been a while, but I'm pretty sure that the heads & intake were gasket matched.

[surfsama]

1) Make sure your tires are aired-up.
2) Get the best gas you can find.
3) Make sure you have a video camera(s) ready.

Experiment with your advance and nail it for your combo.

[grivera]

Originally Posted by Speargun

My combo is:
455 +.060 (469cid)
Un-ported E-heads 72cc
10.25:1 scr, 8.7:1 dcr
.

Do you have dished pistons? Just curious how you arrived at 10.25:1 compression.

[CraigGT37]

My son put his Laser on a awd chassis dyno. We made sure the tires were inflated correctly, NO fluid leaks(extra clean-up charge), oil was freshly changed, extra fuel, another set of plugs and tools to change them, and made sure his laptop battery was charged and brought charger just in case.

[Speargun]

Originally Posted by grivera

Do you have dished pistons? Just curious how you arrived at 10.25:1 compression.

Yes. BRC pistons with a 23cc dish

[Speargun]

I hooked up the MSD Digital Programmable 6AL-2 this evening and dropped the locked out MSD dizzy in the car. Now I'm trying to figure out the software to set up my timing curve.

If I'm understanding it right, I set the dizzy at max advance and then use the software to retard the timing back to where it needs to be at a given RPM.
How much max advance do you guys recommend? 36*?
IIRC, I had the old dizzy set up for 18* mechanical, all in by around 3000, initial was around 15* - 18*, and I ran the vacuum advance hooked up.

[grivera]

I know this is an old thread - how did it perform on the dyno?

[Speargun]

Originally Posted by grivera

I know this is an old thread - how did it perform on the dyno?

410.25hp @ 5200 & 459.18tq @ 4350 at the wheels.


12.02 @ 113.58 and a 1.84 60' on a dirty track & bald tires.

[Speargun]

And then I broke a rod on Christmas day 2019.

[steve25]

Sorry about your breakage, but your low level of HP and Torque for that motor combo on the chassis dyno was a sure sign that something was not right.

[Formulajones]

Didn't look all that low to me. Greatly depends on the type of chassis dyno, but even assuming the more generous DynoJet, that would be about a 500hp engine at the flywheel and somewhere around 560-570 torque.

That's about where I'd expect a decent 455 with out of the box unported heads and that camshaft to make. Doesn't look out of the ordinary to me.

[steve25]

Are you kidding me!
My Brothers 2006 Vett with just a Cam change and headers made 456 HP at the rear wheels and that's with near 100 less cid!

Your too easy to please!

[Formulajones]

Originally Posted by steve25

Are you kidding me!
My Brothers 2006 Vett with just a Cam change and headers made 456 HP at the rear wheels and that's with near 100 less cid!

Your too easy to please!

Well, I am pretty easy to please, lol

But.....
You're talking about an LS engine. Different animial, I've had plenty of LS cars on the chassis dyno There's a reason why the LS swaps are so popular Not to mention the vette is using a pretty efficient transaxle setup (had one of those too) and does a good job of putting power to the tire.

Fact is, a 10:1 455 built like the OP has, with a 236 @ .050 cam, unported E heads out of the box, is going to be about a 500hp engine give or take. Which will put somewhere around 400 to the wheels by the time the trans, converter, and rearend soak it up, along with all the accessories, air cleaner, and exhaust system.

[Scott65]

Uh oh, the "L" word's being thrown around...

[Formulajones]

Originally Posted by Scott65

Uh oh, the "L" word's being thrown around...

What can I say, if ya wanna make easy power with just a cam swap, it's LS baby!!

LOL

[Scott65]

No doubt! Doesnt bother me at all. I'm gonna build one myself someday...

[steve25]

A typical 9.5 to 1,.030" over 455's with a hydro roller, iron heads ported to 260 cfm@28" @ 600" , but running only .550" lift will make some 480 hp at the flywheel
480 hp means the motor was using only 240 cfm of that 260 the heads could pass.

[Formulajones]

Originally Posted by steve25

A typical 9.5 to 1,.030" over 455's with a hydro roller, iron heads ported to 260 cfm@28" @ 600" , but running only .550" lift will make some 480 hp at the flywheel
480 hp means the motor was using only 240 cfm of that 260 the heads could pass.

Yep, I've seen a bunch of these combinations that are very similar, and built a few. They all seem to fall into that HP and TQ range unless you get really crazy with cam timing and compression. Then people complain about street manors.