Don Terrill’s Speed-Talk

I have ported a lot of these, typically intake valve guides are perfect and exhaust is lose and I end replacing only the exchaust guides. Heating does not make sense as heat expansion rate between aluminum and bronze is almost the same, heating to 100C degrees gives ~0,003mm difference in size (bron...

Liners definitely are tighter in place after broaching. I broach liners untill they dont expand / next size broach does not feel any looser after few goes. Then ream to slight undersize and hone to finish. I have not had luck to get them straight with a broach only and end of the guides are tighter ...

Lexus ct200h here. Slow as what, but takes me to work and back at city traffic. Its not fun at all, but costs are low and I could not use ever the 5.0s 0-60mph that I had with my previous Audi S3. Lexus had to go and changed to Audi RS3 for a few years.. absolutely loved that car. But due to gasoli...

Width, angle or need of a back cut depends a lot of the seat profile and venturi diameter. Its best to test with a test valve if available to measure and learn, or just take the "risk". I typically use seat angle -15deg as back cut, all the way to the seat. If throat is big, less angle or ...

Are you able to model the flow of Chads port with 28"h2o delta pressure to compare how CFD matches real world measurement as a baseline?

Darin was previously showing burn marks and carbon deposits of a ran head, which matched almost identically to his Dykem testin on flowbench.

At work we don't use die grinders to develop heads and manifolds anymore No spreadsheet calculators or mcsa recommendations from hot rod chevy magazine either It's way easier to program 5 axis cnc, when the the surface in the file you designed was used to make the casting :mrgreen: How do you come ...

Example, customer asked to get HP peak and about 230hp from Opel ecotec 1.6L engine at 9000rpm I would say that with intake limitations, first shot to this engine type and head, it would had been impossible from me to hit the target without simulator. Back in the good old days I would had spend days...

It's all about building a data base off what your seeing and understanding the bench data. Guys like Darin, Larry Meaux, Dennis Wheet, Dave Layer, etc. have been setting records forever. I have seen a 20fps change on the floor pick up .10 in ET. It still came down to the track and the score board. ...

Spread sheet can get you really close to 1D simulator results on flow speed if you include the heads flow CD in math to get more accurate delta pressure for speed calculation. I typically just evaluate the ballpark for flow speed limits and potential VE% in excel, but fine tune the combination and C...

Where the HP peaks depends heavily on intake and exhaust cross section areas and tuned lenghts.
If everything is tuned properly, I would estimate that this cam could peak around 7500rpm and have ~240-250hp.

How about nitromethane?
Like 85% or so.

Air goes throug shortest path or path which has lowest resistance.
If you pull a string through port, the shortest path is propably busiest.

It was either Vizard or the superflow 110/120 operators manual said that after .3” of valve lift the port is the main driving force. So my thinking was I could work on high lift flow while I wait for my machinist to catch up (he’s had it for a year now). The 160cfm came from a good head with a dece...

Valve job should make a big difference to port efficiency.
I would recommend having it done before working with the port design.