Don Terrill’s Speed-Talk

this thread is rapidly turning into a book. i have some dart 210 cc heads the same vintage that i worked 10 years ago that flowed about 290 on the intake .thinking about going back through them with some info from here. lots to digest

gnicholson wrote:this thread is rapidly turning into a book. i have some dart 210 cc heads the same vintage that i worked 10 years ago that flowed about 290 on the intake .thinking about going back through them with some info from here. lots to digest

Chapter 2 coming up!

gnicholson wrote:this thread is rapidly turning into a book. i have some dart 210 cc heads the same vintage that i worked 10 years ago that flowed about 290 on the intake .thinking about going back through them with some info from here. lots to digest

I've seen 290cfm beat 315cfm on the dyno.
Be careful what you digest.

Randy

Chad is that 23* head a dart? If so that's a lot of material that's been removed from the ssr.
I would've thought there'd be water in there....

Biteme wrote:Chad is that 23* head a dart? If so that's a lot of material that's been removed from the ssr.
I would've thought there'd be water in there....

Pro-Filer

A quick look on Stan's site and these heads are real close to what some pros produce. Thanks, Charlie

Carnut1 wrote:

Screenshot_2017-02-02-07-07-50.png

A quick look on Stan's site and these heads are real close to what some pros produce. Thanks, Charlie

Which is great news when comparing static airflow numbers. Shows that you did a good job pushing the boundaries.

But I believe the better question should be.. were their pitot's reading the same exact airspeeds around the short turn as your port/s? Maybe just call Ron's and ask if they have any other data or notes on those heads?

cspeier wrote:The first photo is a 23 degree, the second photo is my 13 degree.

Thanks for the replies Chad.

So, to my partially trained eyes it looks like the floor on the steeper valve angle heads is biased towards the center of the cylinder more so than the lower angle heads. This seems to be the trend in the aftermarket and although the layback angles are a bit different(asymetrical).. my 8° Kasse heads have very little apex bias towards the floors short inside corner.

Is that purely a result of valve angle reductions affect on straightening and slightly lengthening the throat section?

Chad,

Nice work on those SBC ports with the 'speed bump'. Any chance I can get all the figures to run through my soon to be published flow bench program??

DV

David Vizard wrote:Chad,

Nice work on those SBC ports with the 'speed bump'. Any chance I can get all the figures to run through my soon to be published flow bench program??

DV

What do you need?

23º DATA

2.98in² MIN (throat)
67cc chamber*
1.390 x 2.400 opening
Mr Gasket 5824**
2.99in² AVG CSA
5.40 port length
265cc runner
2.140/5.255/.065 margin/.290 tipº
1.580/5.240/.080 margin/.290 tipº
50º intake seats
radius 45º exhaust seats
4.155 fixture
1.875 pipe
.200 138/114
.300 210/154
.400 257/191
.500 299/218
.600 326/235
.700 344/248
.800 352/252
.900 358/254
1.00 363/256

13º DATA

3.08in² MIN (throat)
42cc chamber
1.500 x 2.280 opening
3.12in² AVG CSA
6.155 port length
300cc runner
2.180-2.220 valve
1.580-1.600 exhaust
50º seats
4.155 fixture
.200 150/94
.300 227/135
.400 294/195
.500 349/224
.600 386/247
.700 403/261
.800 410/274
.900 414/281
1.00 418/287

Chad, I hate to be a pain here but, just for the 23 degree head, I need the flow figs at 0.50,0.100, 0.150, 0.250,and 0.350 for all the trend and number crunching.

Also, for 23 degree head I need center line length of an intake and an exhaust port. With that I should be good to go.

Thanks
DV

first vs. Last flow test. This had the Slight backcut Manley valves and tulip exhaust valves

flow per sq in graph.

Port energy as cast vs. ported. This is compairing a 203cc intake against a 248cc intake. 1204 intake size vs. 1206 intake size, 77cc exhaust port to a 91cc exhaust port. Not a stellar victory but a good try. I believe these are still capable of our 700 hp target. Interesting program that really helps aim the porter in the right direction. If D.V. finalized the port energy section a bit sooner you can bet I would most likely made these a bit smaller. I am still quit happy but not fully satisfied with the results and would like to give special thanks to D.V., groberts, Randy331, CGT, Chad, Eric, and many others who helped on these. Charlie