Head flow data

[Twisted Steel Performance]

Finished up the work on my P400 heads now all that's left is to finish the coating on the combustion chambers...
This data is a direct apples to apples test, P400 before and P400 after, the heads have both bigger valves, valve unshrouding, coated runners, 2 angle valve job, ( stage 3 )

These heads made a visit to the flow bench 4 different times during the process and the flow was measured every .050" lift...

 

[ak diesel driver]

Nice

 

[93detroit]

175cfm @.250" is huge.
Can't wait to see what you feed and compress all that flow with!

 

[Twisted Steel Performance]

A DB2@161cc's and a HE351VE controlled with a banshee controller...

 

[93detroit]

Wow! Adjust your headrest properly to avoid whiplash. Nice work!

 

[Will L.]

Soooo anxious waiting for the dyno results.

 

[Rockabillyrat]

Awesome work! id like too see dyno results of stock heads vs your p400 heads. I'm still not convinced port work is needed on this platform.

 

[Twisted Steel Performance]

I guess "needed" sort of depends and has as many answers as people asked, my past tells me it will help in lots of ways that may not be seen.

 

[Twisted Steel Performance]

I wish i could find a dyno set up for this platform, I'd like to test several things.

 

[MrMarty51]

I guess "needed" sort of depends and has as many answers as people asked, my past tells me it will help in lots of ways that may not be seen.

Extra flow could help to dissipate more heat.

 

[Rockabillyrat]

Saying that its "needed" will depend on what your using the truck for. Racing and pulling where the engine sees 5k rpm. Then yeah I could see big heads, cam, and turbo combo being needed to feed the top end. A street driven truck used for towing, your probably doing more harm than good with the bigger set up since your hurting the lower end by lowering port velocity. You have to pick what RPM range you want to focus on when setting up the heads. A VGT could help counteract that loss of port velocity so it may not be as noticeable. Same goes for a fully divided hot side with a twin scroll. I would just be worried that big heads, cam, and turbo on the factory open hot side will be too laggy on the street.

It would be awesome to graph the boost pressure relationship to RPM between stock heads and your ported heads to see what effect it has on spool time. It might be so small its doesn't matter either way.

 

[Twisted Steel Performance]

I'm a little surprised no one has mentioned the exhaust side out flows the intake for most of the lift.. and I'm building for 2500-3000 rpm and a weight over 20k all the time, so we will see.

 

[Rockabillyrat]

I completely over looked that!!

I know there is math out there that can help match a turbo to the engine based on CFM numbers. I'm at work so I don't have time too look but with the heads flowing over 200cfm on both ends x 8 cylinders would mean the engine can flow 1600cfm? (Of course that would require all the valves to be open at the same time, and only 4 valves open per one crank revolution so im sure that is not accurate).. and a HE351VE flows 800-900cfm.

 

[MrMarty51]

I'm a little surprised no one has mentioned the exhaust side out flows the intake for most of the lift.. and I'm building for 2500-3000 rpm and a weight over 20k all the time, so we will see.

Just My personal thoughts that, once the heat of combustion is added to the exhaust flow, that flow will increase quite a bit more. But, I aint real smart on such matters and there might be a lot more play into the figures so I might be wrong on My ass-umptions. .

 

[93detroit]

I was referencing exhaust flow in my post, I should have been more clear. My bad

 

[Rockabillyrat]

I had a few minutes at work so I ran the 6.5 though a few popular online CFM calculators.

a 6.5 at 4000rpm making 20psi needs around 900cfm

So the HE351 would be a good turbo to match

a 6.5 at 4000rpm under atmospheric pressure (no turbo) requires a minimum head flow of 150cfm.

 

[Twisted Steel Performance]

Thanks,

Those numbers look familiar, I may have used a similar calculator at some point...

And the VGT I think will compensate for the lower rpm area, and I am more concerned about on road at speed not stop and starts...

 

[Husker6.5]

@Twisted Steel Performance, sounds like you're building for a heavy hauler, not a stoplight to stoplight racer. Just read this thread and looked at your flow charts, impressive gains on the exhaust side (intake not so shabby, either) that should show up in ability to really spool up that turbo at mid to upper rpms and being VGT shouldn't have much problems spooling up off-idle, either. Yeah, be interesting to see engine stand and rear wheel dyno numbers for the finished build.

 

[Twisted Steel Performance]

I haven't found a engine dyno in driving distance willing or capable of running it, and I'm not a fan of chassis dyno's other than tuning , there are a couple around but they don't really want to run a diesel... I'm almost ready to send the info to my cam guy and see what he comes up with for the best cam profile then see if the cam can be made and how much dollars that may be... the cam guy has already said from the specs he has seen so far a new cam would be needed... we will see soon...

@Twisted Steel Performance, sounds like you're building for a heavy hauler, not a stoplight to stoplight racer. Just read this thread and looked at your flow charts, impressive gains on the exhaust side (intake not so shabby, either) that should show up in ability to really spool up that turbo at mid to upper rpms and being VGT shouldn't have much problems spooling up off-idle, either. Yeah, be interesting to see engine stand and rear wheel dyno numbers for the finished build.

 

[Husker6.5]

Yeah, shame about the engine dyno situation. Perhaps after it's all built and installed you can show up at a diesel event somewhere nearby that has a portable chassis dyno and maybe shock a few people with an "antique" and "obsolete" 6.5TD that spins the rollers at 400+hp!