L31r goodwrench crate with about 1k miles
t5 wc. Stock replacement clutch
Stock edelbrock pro flow xt intake
ls1 tb with a 4inch intake pipe to a conical k&n
hedman shorty headers with the y-pipe cut to a 3inch join, magnaflow single cat and a 2.75 mild steel I-pipe back to a 3inch magnaflow muffler
lt4 hotcam with stock stamped 1.5 rockers
30 lb injectors
32deg timing peek
ebl flash - much tuning still to do but wot fuelling AFR was around the low 12mark

whilst was hoping for a bit more, with likely the exhaust holding me back a little; but overall pleased. The nearly flat torque curve is interesting!

mostly just wanted to add to our library of dyno charts. And haven’t seen a pro flo graph up

 

Is this a chassis dyno?

 

Dyno Dynamics is a chassis dyno type.

 

The Hotcam has a very flat torque curve. There is a reason I have used it in L31 powered trucks, suvs and vans with the L31 or the practically identical Lunati Bare Bones or Comp XM270HR grinds. My pontoon boat also had the XM270HR. I propped the boat to spin 5,100-5,500 rpm at WOT depending on how loaded it was.

 

Yep was on a roller dyno. Just crazy how flat it is. I suppose area under the curve that’s pretty ideal albeit the number is a bit lower than what other people seem to get with the l31 hotcam combo

Horsepower is at the flywheel and the operator mentioned about a 19% conversion for wheel power. So slightly under 300 at wheels. Given I have a t5, probably don’t want much more. But I can see me chasing around 320 at the wheels in the summer and have a t56 tucked away!

 

I have that cam in my zz430 clone w a pro flow XT setup. It's drives awesome. I haven't gotten it on a dyno yet. It's getting a torque storm blower this winter and tuned after. As a N/A engine it's great.

 

i was gonna ask if that was flywheel estimated because it seems high for wheel hp for that combo. But the hotcam always done well in the few i tuned. Nice broad powerband

 

indeed it is a fun drive. Decent torque from down low and revs up quickly. Manners around town also good!

 

There's certainly something to be gained with a more efficient exhaust. I would suspect that the single muffler is a considerable choke point.
Nonetheless, those results would still be satisfying.

 

Interesting. I understand magnaflow mufflers to be pretty much straight through. Was thinking the single 3inch cat might be a restriction

 

Magnaflow doesn't have published data that I could find. However, depending on which muffler you have there might be comparisons that could be made.

As an example:


There is a general rule of thumb regarding flow requirements vs engine output.
2.2 CFM per HP (crankshaft) before the restriction starts to reduce output. It's a diminishing returns kind of deal but with a 450 HP, you're looking for a combined exhaust flow of 900+ CFM for what might be considered a zero loss system. I can't think of a single 3" muffler, other than a "race bullet" along with piping under 3" that can accomplish that.
This is why I'll have incorporated cutouts at an appropriate distance along the collector length to open up on track days. Or dyno days for that matter.

 

That is one flat torque curve. I always thought the hot cam is a great combination with the Edelbrock pro flo xt.

Fred