Thread: Head Flow Testing
03-08-2012, 08:40 PM #1
Head Flow Testing
I need a donor head for a project. Looking for an old 4-Tec head thats maybe damaged that someone is willing to donate to a good cause. I went out to Mike Steels racing shop today and spent about two hours with him going over some of his porting and testing methods. This guy is the guru of head porting and after looking at some of the work posted in the forum he seems pretty confident he can improve flow dramatically. The guy has been doing this type work for over 30 years and is considered one of the top porting specialist in the country. He was able to demonstrate some of the suttle changes in the exaust and how big a difference it makes in the flow numbers.
Check out his site below,
03-09-2012, 07:31 AM #2
Before I start getting a ton of PMs let me clarify a couple things from my previous post. We looked at some of the porting work on the forum and he had no negative comments on the ones we looked at. He simply sees areas that could be improved a bit, in some areas by even adding material to the OEM cores. This could only be verified by making suddle changes and then flow testing. They guy is very maticulous, could take a week to do one chamber.
03-09-2012, 08:06 AM #3
im actually working on a cylinder head for duke right now that is going to be my most involved and time consuming cylinder head to date. I have recorded before CFM flow numbers, and everytime i made a change to the port/chamber i have re- flow tested it and recorded those gains, im over 20 hours of porting time right now, and still have to install the larger exhaust seats and valves. There are a few of my very early ported heads that i did that were not as high flowing as the ones i do now, because i was being very careful as to not take alot of material off in the wrong areas and/or port through to a water jacket. i have actually contacted a couple people ( that i can remember) and told them i would update their heads with the newest porting program the next time they had their head off the ski.
The problem with alot of porting shops ( not saying anything directed towards your friend Donnie) Is that they think bigger = more CFM gains, which is not always the case. On the early Mitubishi engines i have actually welded the floor of the intake port and closed off a decent amount and re-shaped the port and saw serious gains on the flow bench and there was hardly any turbulence compared to the stock port.
If you ever need any information to help your project give me a ring. I will help out in any way i can.
03-09-2012, 08:30 AM #4
Your comments are in line with his way of thinking with the exception of gained CFMs through the head. Are you suggesting that the head can flow too well? I can see this becoming an issue if not funneled correctly through the exaust. It was also noted that there were issues with the heads design, specifically in the location of the valves. They sit right next to the bores causing a significant increase in flow turbulence. This may be a trade off due to the room needed for four valves per cylinder and the room needed to accomidate larger valves.
I really dont think there is anyone better at porting heads than Mike, maybe some equal (friend or no friend).
03-09-2012, 08:58 AM #5
This is what i have noticed on huge port 4 tec's
1) Bad idle, lopes like it has a cam.
2) Throttle response is non existant
3)Transition from part throttle to WOT isnt crisp, its very choppy
4) Recovering from comming un-hooked is bad, ski falls on its face ( almost like a bog)
03-09-2012, 12:27 PM #6
Anyway enough rambling, we may just have to bite the bullet and buy a new OEM head to cut up! Have you got any recent flow numbers for your latest portings? OEM vs. Yours. I know I remember seeing huge gains from your work before. I can tell ya that I am completely happy with the work you did on my head, it performs very well.
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By dhoad in forum 4-Tec PerformanceReplies: 13Last Post: 10-07-2009, 11:08 AM
By syclonedriver in forum Yamaha PWC Performance (2-stroke)Replies: 15Last Post: 10-07-2008, 07:27 AM
By 58vwragtop in forum Kawasaki Open DiscussionReplies: 1Last Post: 08-09-2008, 06:52 PM
By Gatorcountry in forum Yamaha PWC Performance (2-stroke)Replies: 9Last Post: 11-13-2007, 09:12 PM
By PWCManiac in forum Yamaha PWC Performance (2-stroke)Replies: 24Last Post: 12-21-2006, 09:01 PM