Re: Experts: Runner length and volume?
 

A 9:1 motor with a bs of .39 somthin, how do you do it? :eek:

Re: Experts: Runner length and volume?
 

If I remember correctly those numbers were way off because of the return style fuel regulator,I rely more on the wide band 02, A/F ratio, and EGTs. I believe on the N/A motors I was running 12.6 a/f and right around 1375 degrees. Timing would have been at 36. past 3000 rpm.

Re: Experts: Runner length and volume?
 

GPM,
How much spring do you run with the HT 440 lobes?
Bob

Re: Experts: Runner length and volume?
 

I believe they are 285 at the seat and 730 open, I use the Crower 68806.

Re: Experts: Runner length and volume?
 

You engine builders may have me at a disadvantage here, this is only a hobby for me. I do have a question for you, what do you think the difference is between the blower motors on page one?

Re: Experts: Runner length and volume?
 

Hehe...your killing me Smitty! John doesn't know it's missing yet! yep, runnin a 96/272 Baja, I seem to have a problem with the haul, haven't busted 80 yet! Should start another thread for this maybe? Do you talk as fast as you type? :D :D
-Ken

Re: Experts: Runner length and volume?
 

How does runner size correlate between an injected and carbed motor? Can the runner size be smaller on an injected motor due to the fact that there is no fuel present, which takes up space? I know on carbbed alky motors runners and ports need to be huge to accomodate the large amount of fuel required. If smaller runners are used in a dry manifold it seems the ram effect can be maximized compared to using the same runner cross section as a carbbed motor. It is probably splitting hairs, but fun to talk about.

Craig

Re: Experts: Runner length and volume?
 

GPM
I am no engine builder but I have a guess. Is it possible that there was a cam change between the two procharged motors on page 1?
Craig

Re: Experts: Runner length and volume?
 

If your referring to the dyno sheets, the second sheet is NA motor, if your not diregard my reply.
-Ken

Re: Experts: Runner length and volume?
 

Kennywould you're on the wrong page. Wette Vette, It wasn't a cam change. As far as the runner size, my opinion, they should look like a funnel, and flow at least as much as the best port in the head. A stock Dart tunnel ram will only flow 354 cfm per runner. Whats the point in running a 390 cfm port,if you are going to hold it back with the manifold.

Re: Experts: Runner length and volume?
 

Ken,my boat stops accellerating completely at 78-80 mph UNLESS its trimmed right to max but i'm sure youve already tried this with your boat. I'm turning a 30 pitch lab at 5400 with ALOT of slip. I bought a 32 pitch from houston prop in the fall,boat went 84.7(if i remember right)but next season i'm hoping to see 90mph. I also had smallest blower pulley on with 32 pitch(i was seeing 5200 ). At beginning of this season my motor still had less than 10% leakdown,at end of season i had cylinders at 35% :eek: ,motor has 140 hours(2 seasons) on it,i'm freshening it this winter and changing cam,putting afr cnc's on it and bigger injectors and doing something with intake(still undecided),Smitty

Re: Experts: Runner length and volume?
 

That makes sense GPM. I had a buddy that ran a 900 HP NA 632" (pump gas) and he ran a Dart tunnel ram. It was fully hand ported probably to get the intake to match his 420 CFM intake ports. So are you going to tell us what was different on the motors between the earlier mentioned dyno pulls? I am assuming you know the answer and are just testing us. Maybe it is the differance between an older Procharger vs the M5. Give us a hint!! :drink:


Hey JIMV,

Ever flow heads with an intake bolted up and is it even possible?

Craig

Re: Experts: Runner length and volume?
 

It was the same motor, blower belt started slipping on the 1200hp one, slowed the blower down for the 1372. Imagine a cog system. We always check head flow through the manifold looking for restriction.

Re: Experts: Runner length and volume?
 

Craig, I do it all the time. The Dart manifold knocks the flow back about 6% depending on the runner. A tunnel ram about 3 %. I flow them with carbs, and the runners blocked off

Re: Experts: Runner length and volume?
 

Chris:

Sorry for the delay the block is up at Roush in Detroit right now and they will be done with it on the 24th. I will get it to you then and you can start on our new trick oil pan.
Thanks for reminding me. so damn busy!
Regards,
Ray @ Raylar

Re: Experts: Runner length and volume?
 

Smitty, I found a picture, it's from a more recent project, tunnel ram EFI.

Re: Experts: Runner length and volume?
 

Heres my 565

Re: Experts: Runner length and volume?
 

In simple terms, the taller the intake (tunnel ram) the higher (rpm) the power band?

Re: Experts: Runner length and volume?
 

No , not neccessarily. A taller tunnel ram with longer runners of the same area or size as a shorter tunnel ram would tend to have its max power at a lower rpm with more torque.
Longer runners generaly develop power at lower rpms and at very high rpms they tend to restrict the engines breathing ability and is obviously camshaft size and duration dependant.. Your intake, cam and exhaust system has to be tailored to where you want your power band.
Ray @ Raylar

Re: Experts: Runner length and volume?
 

JimV: Is that a Dart tunnel ram on your engine? Where is the power band on that combo?