NewbVetteGuy

Holy #@$%^#$% that .600 and .700 flow is looney!

I had only compared the AFR 180s to the Profiler 185s and the AFR 195s to the Profiler 195s and they were shockingly similar; but with the 210ccs the AFRs really pull away at high lift.

Beastly!


Adam

NewbVetteGuy

And if I'm not mistaken you've paired the Profiler 195s with a FIRST Fuel Injection intake, right?

Any dyno results? We're staring at near identical builds right now....



Adam

NewbVetteGuy

Larger exhaust duration to make up for the reduced exhaust flow?


Adam

NewbVetteGuy

You got 500ft lbs with Profilers in a 383? Have the dyno results / curve posted up anywhere?


-You ever go to any area Corvette events or are you in a club? I'd LOVE to check out your car sometime (I'm in Woodinville.). -It could give me some extra motivation to push through my build and start the top-end sooner. (I've been planning on doing the heads and cam NEXT winter but I'm starting to get antsy...)






Adam

Silvertone

Hi Adam, I can probably find the dyno sheet I got from ATK. It's a variation of a crate 383 from ATK called the HP55C. I actually had them go with a slightly smaller Howards Roller, HEI, and vacuum secondary Quick Fuel 780 to meet my specs for a decent street build. I got the Pro Filer idea from a good friend/neighbor that has an 8 second Chevelle. A lot of big block racers use them.

Steve

ezobens

Adam,
You are correct-
I'm just finishing the final touches on the FIRST install with sequential injection. The car fires up and runs but I have not had it on the street yet. I wasn't formally planning to dyno the car but that is always an option but most likely won't happen before next Spring / Summer.

pauldana

Thank you,,, i have around 525tq/hp at the rear wheels.. RWHP

Silvertone

Well, I hope you own a tire dealership!

NewbVetteGuy

Thanks Steve. I know exactly who they are. They have their own casting of the profiler heads- identical intake and combustion chamber, but regular height exhaust.

500hp / 500ft lbs -that's my dream 383 there, except that my dream 383 would be EFI. Great motor you've got there.


Adam

NewbVetteGuy

That's. Not. Normal.

I bet you have way too much fun trolling C4s, C5s, and C6s...

You should put some cameras on that thing and open a YouTube Channel called "C3Troll" -really lay it on thick about it not being a fair race against your old "smog motor" with "chariot suspension". ;-)

Hmm... Now I want to buy "SmogMtr" as my Washington vanity plate for my 79... Lol! Just checked; it's available!


Adam

StraubTech

If something is slower don't you have to give it more time?

Kacyc3

and use the line its just a small block chevy.

NewbVetteGuy

You do (people and ports, I guess).

I haven't seen the speed numbers on an operating Profiler head's exhaust port though; just CFM total flow #'s.


Darin Morgan's article on flow #s from February of this year, and specifically the Exhaust Port Design paragraph makes me wonder whether the Profiler heads' exhaust ports flow far better at operating conditions than on a flow bench. -I'd LOVE to see back-to-back dyno results on these heads with only the exhaust duration changing between runs....

http://darinmorgan.net/frank-talk-about-flow-numbers/


[edit] Today I've been trying to get a glimpse into Darin Morgan's thoughts on exhaust flow after coming across the article above and after pondering the differences between the AFR and Profiler exhaust port flow #'s for a while now.

Apparently he's laser focused on getting the intake side right and then the exhaust just flows as best as it can with the space that you've got left for the exhaust valve- his experiments that he's hinting about seem to indicate that improving the exhaust flow doesn't really help you to build more power as you can just increase the exhaust duration a little bit.

-As I'm just super focused on maximizing torque, I now have to think there's some torque advantage to the AFR's increased exhaust flow and therefore decreased exhaust duration; it seems that when you've got a lesser flowing exhaust port you're stealing from torque and giving it to HP by increasing the exhaust duration. (That's my best guess today, I reserve the option ot change my answer tomorrow, though. lol!) -It also seems like the great exhaust flow of the AFRs becomes increasingly important if you go to forced induction / NOS as you'll have to get into increasingly large intake/exhaust splits to make up for it...

Joe Sherman seems to back this idea up in his post to the same thread on SpeedTalk saying that increasing the exhaust lobe duration really only provides a benefit at high RPMs when the extra exhaust flow is needed, but that you're stealing from torque and he's found that single pattern cams can often make the car run faster if you're not spending your time in those high RPMs...

-So it seems like the AFR heads' great intake to exhaust ratio really makes it so you don't have to decide between a bit of low end torque vs. top-end HP; you can have your torque cake and eat it too (HP) if you shell out the extra $$ for the AFRs.


http://speedtalk.com/forum/viewtopic.php?t=4214

With my long-runner FIRST intake I'm kind of walking right up to the detonation limit where I am right now so slightly decreased pressures might not be all that bad for my build..

Adam

gkull

At what degree range AFTER TDC do you have at or near max piston speed. Like 45 degrees to 135 degrees with the peak being at 90 degrees?

I pulled up a typical 242/248 HR cam. At .050 lift numbers the valve events are I open 15 BTDC closed 47 ABDC. Max valve lift is at 121 ATDC.

That would tell me that the valve is not fully open till 121 degrees ATDC, but already in the highest lift areas of the lobe between the 45 and 135 atdc where you have max piston speed.

resdoggie

Nope. Equal amount of time at tdc and bdc. It's the valve timing controlling cylinder fill.

StraubTech

Not correct. A poor flowing exhaust can make very nice flat torque if it it is correctly cammed. Some of the GM ls head casting are very poor IE ratio but make very good torque. I posted a 396 BBC on here a couple of weeks ago with OEM heads and poor exhaust ports. Torque was pan cake flat.

You cam for what the intake can do and what the exhaust can do. Both valve paths end up on the camshaft together.

larrywalk

Sorry, not correct: As the rod-to-stroke ratio becomes lower, the dwell near TDC becomes shorter and the dwell near BDC becomes longer.
Only if the connecting rod is infinitely long can the time around TDC be equal to the time around BDC.

gkull

StraubTech You seemed to not answer this?

pauldana

it can get expensive:-) I'm on 180 tread ware now and it just not happening..I literally can be on the freeway at 70-80, mash on the gas and lay a sustained burn out on anything more than 200 ware tires..

Gosh,,, you have pegged one of my favorite things to do,,, its funny as heck, they never see it coming... But I do remember their was this Cobra on the 101, and it walked away from me like I was standing still... Caught up to him at super Car Sunday... he said he was 800hp at the rear wheels and 2400lbs... I believed him,, Wow he was fast,,

cv67

got a ride in a members CTS-V that makes in the 7s at the tire
anything less than 3rd gear was useless even at that he had to roll into the throttle so it wouldnt spin
holy smokes could NOT believe how hard that thing pulled
80-150 in nothing flat seemed like. Things happen to fast at that speed, was fun but not for me. I prefer getting to the speed limit quick and thats about it anything else is a loss of license, job trip to jail etc not worth it. Deep gears and a manual forever.