DOHC Head Airflow Data

[BMFH]

Hello All

Is there any published Stock versus Ported Airflow data around for this engine? Or would anyone like to give an idea of the potential flow of the heads.

I would like to do some computer modeling with it.

Thanks In Advance

John

[dohcfiend]

*whistles* those silicon circuits are so sexy.lol. im a little buzzed and couldn't resist. but can't help you

[pocket-rocket]

There is a guy on the Pennock Fiero forum that did some port work on a set that had them flowbenched. I think his screen name was DKOV? He was also working on a 6 speed manual too, so that might help you find him easier.

[Anonymous]

You can talk to SappySE107, he has done some head work in the past.

[pocket-rocket]

But he has no flow numbers since he hasn't gotten his flowbench up and running.

[Anonymous]

You also have P&P heads right?

Did they even add much over stock? Becuz our factory heads are pretty well set up. In my mind, I doubt they'd even need much porting, maybe just polishing and removing rough parts, etc.

[pocket-rocket]

Ask Michael. He rode in the 91. His exact words were "Holy shit! You have low end nut!" Most of the work was cleaning up the casting flaws because there were quite a few in the heads on the 91. I can't say a ton about how much they improved things because I wasn't quite used to the 5 speed after the auto came out before they were done. But yes, the ass-dyno noticed a difference, even with a clogged cat. We also did the alternate cam timing when they were on, so it wasn't like we did it all a little at a time, and got slips for each mod. But yes, they were a good improvement. Ben's porting skills have gotten better since then, and he employs better techniques now.

[SappySE107]

The problem with the head porting flow numbers I have seen is the lack of any gain at all till .200" lift. Thats not good when we only have .370" lift to begin with. I wish I had the bench going so I coudl flow the heads going on my car. The gains though are substantial from porting, and it can also hurt performance if you do it wrong. Im trying something new on my heads now but it will be few weeks before I know the results.

I can give you the stock numbers within 3cfm based on the screenshot I got from DKOV.

intake
.050 42
.100 84
.150 135
.200 170
.250 200
.300 227
.350 247
.400 260

exhaust

.050 25
.100 75
.150 110
.200 130
.250 150
.300 165
.350 167
.400 170

And these are the ported head values from DKOV.

intake

same till .200

.200 173
.250 210
.300 243
.350 269
.400 292

exhaust

virtually the same till .300, little up and down within a few cfw compared to stock

.300 169
.350 180
.400 190

[Gemmer]

didnt DKOV port the 96 heads though? Also, if I recall, weren't there a few things ben did differently?

[SappySE107]

Those are 91-95 heads from what I remember. Im sure I did a few things differently, but its been a while since I have seen the DKOV heads. Ive done a few different attempts at the heads though as well. I found a flaw in the lower intake this time around so im hoping to see what does along with the head porting.

[BMFH]

Hello All

All this information is great, I knew the engine flow numbers would be good for a 4 valve engine, The flow data looks great, now I have something to plug into the computer.

I am planing on getting a vehicle with this engine and would like to see what I can do to improve on it.

Thanks Loads Guy's

John