Anyone have flow bench numbers?

[dallarax19]

I am getting ready to start to port the heads and want to know what people have done. Flow bench data would be primo. I have found a few differences of opinion on the port shape and lead in for these heads. I am particularly concerned with the exhaust port treatment. Links and or data would be super cool.

[dmc6960]

Back in 2009 I rebuilt my engine. I installed high compression pistons from DMCEU, milled the heads by 1mm, rebalanced the rotating assembly, lightened the flywheel, installed the DMC Stage I exhaust, and had the intake and exhaust ports ported by a racing company in town. They took before and after flowbench data. Material was removed from the sides of the valve support buldge in both the intake and exhaust ports. The EGR ports in the exhaust were filled in and completely removed.

Here are the flowbench numbers...



Intake

1.730"

Stock
/
Ported



Lift
.100"
.200"
.300"
.400"
.500"
.550"
.600"


%flow
0.23/0.23
0.39/0.41
0.45/0.49
0.53/0.58
0.58/0.64
0.60/0.66
0.61/0.67


CFM
67.4/67.4
114/120
132/142
156/171
170/188
175/193
178/197



And the pictures to show the afterwork. Here is the intake...

http://dmctalk.org/attachment.php?attachmentid=21532&d=1377197281

And here are two of the exhaust. You can see how the EGR port was filled in and removed...

http://dmctalk.org/attachment.php?attachmentid=21531&d=1377197281

http://dmctalk.org/attachment.php?attachmentid=21533&d=1377197292

This work was not cheap, but I have no issues posting information about it here. These numbers also are not the absolute best possible. This was done buy a professional company but probably with not specific PRV experience. They didn't have multiple heads to work with to experiment and find the absolute best design possible. I believe Josh at DPI has done that as he reports getting 250 CFM though the heads with his latest iteration. Thats much higher than my 197CFM.

[dmc6960]

Well, there is supposed to be a table in that with the intake numbers. I have the exhaust ones as well but I'm unsure why the table isn't appearing.

[dmc6960]

Well, it isn't as pretty as my table was going to be, but here is the raw flowbench data. May take a minute to read whats here...

http://dmctalk.org/attachment.php?attachmentid=21537&d=1377204171

[delornut]

I am getting ready to start to port the heads and want to know what people have done. Flow bench data would be primo. I have found a few differences of opinion on the port shape and lead in for these heads. I am particularly concerned with the exhaust port treatment. Links and or data would be super cool.


This was from an '03 DeLorean Mailing List post. Not much for flow readings but interesting.

Bruce Benson



Performance Modification of the PRV

--------------------------------------------------------------------------------

Created: 8/16/03

Last updated: 8/29/04 - added supercharger

--------------------------------------------------------------------------------

Author/source: DML

EDITORS NOTE - This was in a Volvo, not a DMC, so your mileage (and parts fit) may vary. As they say - Speed costs Money, how fast do you want to go?

--------------------------------------------------------------------------------

This information was supplied by Mr. John Lane of Pacific Rim Automotive in
Seattle Washington. John as given his recipe for making his PRV powered rally
car into one fast machine.

Sincerely,
Michael

------------------------------------------------------------------------------

Subj: Re: PRV 500 HPs?????
Date: 04/09/2003 8:41:10 PM Eastern Daylight Time
From: jlane@(John Lane)
To: Senatorpack

Hello to all who are interested in making their PRV break drivetrain parts.
I have been hugely successful in doing just that.

I have had a number of queries as to how I have made my toy just sooo darned
silly fast. Here goes.....

I am using the engine block with the cross-bolted main bearings and oil to
water oil cooler as used in the Volvo B-280.


I am using the cylinder heads of an Eagle Premier/Dodge Monaco, as the
intake ports of the Premier are MUCH better then Volvo used. Set them side
by side to see how Volvo managed to choke the V-6 back to making less power
then the turbo-4.


The heads got ported on the intake side to tidy up a bit, and a LOT in the
exhaust to help that ugly mess.


The camshafts of the Volvo flavor will give better top end power, and alloy
rocker arms are readily available from Volvo. The Volvo cams are of the
mechanical variety, so you will get to adjust valves. I have not tried the
Premier cams with their hydraulic valve lash adjusters for anything but a
street engine, but in that form it ran just fine naturally aspirated. The
Premier cams are certainly of the flavor which will make for more low end
power.


I use the throttle body as used in the Volvo engine as it is of larger
diameter, and it is aimed better for the turbo.


For pistons I am using J&E forged slugs with a dish in them to drop
compression to 8 to 1.


I am using the liners from the Premier for three liters of displacement.
More cubes is more fun all else being equal.


I have learned the hard way that the standard connecting rods are not up to
the task. When it blew up, all the rods except for the one that made
shrapnel were shorter by one to two mm. Too many parts were missing from
the broken rod to guess how much shorter it was before it expired. Yikes!!
Forced induction will push a LOT harder on everything.


My answer for that was to pick out an Eagle Racing connecting rod (think
Merikanski V-8 stuff which is made by the bajillion and therefore relatively
affordable) which is close dimensionally to what we need and have the
machinist go wild to make 'em work. Lots of effort for rods which have
not had to be babysat since. Just the way I like 'em.


The whole rotating mess got balanced with the flywheel and the clutch.
The turbo is a nice big T-04 that I had made up for me based on my
requirements.


The turbo manifold was made up special to get from the exhaust manifolds to
the turbo.


I use an HKS external wastegate, and am as tickled as can be with how it
works. I am not fond of internal wastegates. Boost creep and other
naughtiness....


Oil gets to the turbo via a metal braided hose which is tapped into the big
plug next to the oil filter. I have never checked my oil pressure, but have
had zero oiling issues. If it don't sieze, it has to be all good right? I
use Mobil One synthetic oil.


Oil from the turbo drain gets back to the pan via the hole in the upper pan
(as used in Volvo) next to the hole used for the dipstick. Volvo used this
hole in the 760 for an oil level sensor. We don't need it. We service and
pay attention to our engines right?


The turbo feeds it's warm compressed air to a Ford Powerstroke Diesel
intercooler fitted in front of the radiator. Ignore what the naysayers
snivel about with having a huge intercooler. It is the ONLY way to go
compared with a smaller less efficient unit.


Fuel and ignition is handled with Electromotive laptop programmable fuel
infection and ignition. With this system, or a similar arrangement one can
have perfect drivability with legal emissions and monster power in boost.
Careful though.....One is only a couple of keystrokes away from blowing it
up should you get it wrong. It is the incentive program.....Do Not get it
wrong.


I had the nice folks at Electromotive supply me with the proper size
injectors along with a fuel pressure regulator and all the GM sensors I
needed to do this. It uses a MAP sensor, so no air mass meter to fail, or
be in the way of free flowing air. Now I have a MAP sensor to fail, but
have not experienced that yet.


I am using the fuel pump arrangement as used in later model Mercedes V-8 and
V-12 cars. This an arrangement that the wrecking yard will be happy to
sell you for around $150.00, and it will feed as much power as we are going
to make. You will need larger fuel supply lines.


I am using the exhaust manifolds of the Volvo as they clear my steering
linkage. The manifolds in the Premier look better for flow, but will not
fit in my car without a lot of work. The Volvo manifolds do not seem to be
slowing me down. : )


My flywheel is the Volvo thing; lightened on the brakelathe, and then fitted
with a Quarter Master three disc clutch. The On-off switch which WILL
apply all that power.


WARNING: This combination has resulted in my breaking EVERY part in the
drivetrain downstream of the engine.


It will make HUGE torque, and everything must be up to the task, or you
will have many expensive misadventures with breaking things in inconvenient
places. All in good fun though.


I have had a few folks ask how much dough it takes to do this. The short
answer is a LOT. I did my project slowly over time.......Electromotive got
done while it was naturally aspirated. It made a noticeable improvement
over K-Jet.


This is not a project for the weak of spirit or those of us who are wanting
a very straight forward swap. It is a lot of work, and has made my
rallycar what I believe to be one of the most amusing to drive and watch
here in the states.


I went out of my way to NOT keep track of how much dough I have in this
project......Remember......Complete drivetrain, suspension and brakes to go
with this. One must not just bolt in a stoopid fast engine and expect to
not have to attend to stopping or turning at high speeds. Forgive the
soapbox.


Go git 'em guys and gals.
JohnLane.



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[dallarax19]

You can't get better info than that. It looks like a standard port and blend job which is what I would do as well. There are some details in the port lead in and valve seat angles that could improve the flow even further that I could see if you knew all the little tricks but it is a huge walk from 197 to 250cmf. Do you know if the same vacuum was used to take the measurements i.e. 10in or 28in? I really appreciate the info.

Thanks for the John Lane info. I have corresponded with him before and he is awesome! He however goes for big power but I am looking just for a mild tune. If or when I decide to go for a 3.0 monster I will look for John's assistance. For what I am doing now his perspective is "why bother with a 2.7ltr odd fire engine" - (might be right too)? The guys in France generally keep it stock and the guys in the UK really focus on the turbos (although Pascal Colas (FR) and Martin Faulks (UK) have provided much key info) . This site seems to have more of what I am working toward and data/info for NA tuning.

[dallarax19]

Instead of re writing the info here is another link;
http://212.71.254.48/phpBB3/viewtopic.php?f=8&t=5612&start=285#p70373

After the rough cut I have cleaned up the gouges etc and smoothed it all out. Looks good. I opened up the intake quite a bit more than what I was thinking possible. I will post pics later.

By the way DMC6960 after getting into the port I really like the job your guys did. It looks like they got the most out of it - very cool.

[delornut]

Instead of re writing the info here is another link;
http://212.71.254.48/phpBB3/viewtopic.php?f=8&t=5612&start=285#p70373

After the rough cut I have cleaned up the gouges etc and smoothed it all out. Looks good. I opened up the intake quite a bit more than what I was thinking possible. I will post pics later.

By the way DMC6960 after getting into the port I really like the job your guys did. It looks like they got the most out of it - very cool.

One thing I question is how do you know how much will be too much? When I was still working for Ford I had the opportunity to attend a class done by a NASCAR engine builder along with a drag racing engine builder. When looking at 351 Cleveland heads, for example, the drag racer said there is a point where too much flow begins to degrade performance. It took a lot of experience bench flowing and dyno testing to find that point. I guess what I'm getting at is what criteria are you using for the port opening, simply gaining as large an opening as possible or finding the proper flow characteristic to have the perfect blend of velocity through the heads.

Bruce Benson

[dallarax19]

Hey Bruce, without empirical data it is all just a guess. I have no data on these heads with the exception of the pics and flow data posted - huge thanks again for that :wiggle:. I also have been working with a buddy on a sim for this PRV engine and the general perspective is get the max flow and open up the exhaust port as much as possible. The rest is dead reckoning based on some simple flow principles like fluids like to travel in a straight line so make the direct shot as open as possible. When you get into parasitic losses or loss of flow during transient conditions I certainly could be doing some things that could have a negative effect. The basic assumption is WOT and keeping the mass flow rate as high as possible. Over the years I have had many philosophical discussions about port surface roughness and velocity profile concerning fuel mix, fuel precipitation etc but I have never seen data to support any of this. Honestly the guys that bring those points up are usually the guys that have never built an engine - go figure right? So with that said I have not put this head on a flow bench to obtain data so I have been discussing this topic with several folks around the world, Alpine guys primarily, in France, UK, Washington State, and on this site. For me I am looking at a mild street tune so for the most part the dead reckoning is probably OK. If I was building a race engine I would certainly look at it differently and develop the port for the performance I want, like for a rally car spec (torque for out of the hole accel) or track spec (high rpm hp to carry speed). To do that correctly I would have to generate loads of empirical data for not only the port but the intake manifold as well as the exhaust header to do it right. That isn't in the stars for me on this engine. I hope that answers your question.

[delornut]

Hey Bruce, without empirical data it is all just a guess. I have no data on these heads with the exception of the pics and flow data posted - huge thanks again for that :wiggle:. I also have been working with a buddy on a sim for this PRV engine and the general perspective is get the max flow and open up the exhaust port as much as possible. The rest is dead reckoning based on some simple flow principles like fluids like to travel in a straight line so make the direct shot as open as possible. When you get into parasitic losses or loss of flow during transient conditions I certainly could be doing some things that could have a negative effect. The basic assumption is WOT and keeping the mass flow rate as high as possible. Over the years I have had many philosophical discussions about port surface roughness and velocity profile concerning fuel mix, fuel precipitation etc but I have never seen data to support any of this. Honestly the guys that bring those points up are usually the guys that have never built an engine - go figure right? So with that said I have not put this head on a flow bench to obtain data so I have been discussing this topic with several folks around the world, Alpine guys primarily, in France, UK, Washington State, and on this site. For me I am looking at a mild street tune so for the most part the dead reckoning is probably OK. If I was building a race engine I would certainly look at it differently and develop the port for the performance I want, like for a rally car spec (torque for out of the hole accel) or track spec (high rpm hp to carry speed). To do that correctly I would have to generate loads of empirical data for not only the port but the intake manifold as well as the exhaust header to do it right. That isn't in the stars for me on this engine. I hope that answers your question.

Sounds like your approach is a wise one. I know Jim Reeves is very happy with the head work he had done so the info he contributed is great. I guess I was just curious as there is so little info available for PRV mods involving head flow characteristics on this side of the pond. Beyond some DeLorean owners and the rare Volvo individual like John Lane there just isn't that much out there for the do it yourself modifiers. DMC and Josh's shop have invested a lot in finding the right flow but the results are their bread and butter and so they're understandably reluctant to share that info. As an interesting side light, you mention discussions about port surface roughness. The NASCAR engine builder said they liked a rough surface because their cars still use carburetors and the fuel droplets in the mix cling to the rough port walls creating a much slicker surface than any machined surface. I'd never thought of that but it makes sense.

Bruce Benson

[dallarax19]

I finally got my valve seats cut and port flow measured for one cylinder. I did not get a true "A" to "B" comparison (before / after) so the information is just reference. I was really looking to get larger gains in the exhaust port but in comparison to the intake values it does not look that great. I am not sure why but I suspect the seat angle isn't what it should be. IF I decide to give it another go I will investigate the range of expectation from the angle cut. I certainly don't want to push the port diameter any more and the combustion chamber is stock. Anyway I just wanted to share my data.
http://i54.photobucket.com/albums/g89/dallarax19/AlpinePortFlow.jpg (http://s54.photobucket.com/user/dallarax19/media/AlpinePortFlow.jpg.html)

[Stanislav]

Super awesome thread. Thanks for all the info. Please let me know if you did a dyno test to see how much the flow helped with power. ?