Hamilton Cams
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- Joined
- Jun 28, 2007
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- 2,639
Yes I do think port volume is to blame for poor low rpm performance with daily drivers.
Yes I do think port volume is to blame for poor low rpm performance with daily drivers.
The biggest problem I have seen with our heads in daily driver applications, is not necessarily lack of swirl, but intake port volume that is a bit large for low rpm response.
Stock heads, on my bench have about 3800rpm swirl at .550". The Hamilton head, with some intake seat angles is as much as 3500 rpm at the same lift and slightly less with others. At high rpm they make great power! Under 2200 RPM they will make less power than a stock head, not due to swirl, but loss of port velocity. I have seen stock heads that had less swirl than our head, but yet had small ports that were better on bottom end.
As far as the people that have had issues with our head, in most cases they were using lower than OE compression. The first order of heads was not exactly like the model we used for port developement. On the next order that issue will be fixed with a smaller intake with a better shape.
Joe, your statement on un-shrouding and swirl sounds bogus. He was geting close to 10 before with a set of weston's injectors , and I cut him a deal on the head and to see if it would help in his application. No good deed goes unpunished, right? Working with somebody in testing and getting thrown under the bus will really slow down testing and developement!
bigger Port volume or better port flow in a diesel has little to do with throttle response. First show me the throttle on a diesel. A better cylinder head is better period. Trying to confuse characteristics of a diesel with that of a gas motor will not work.
In a gas motor the lope or sluggish throttle response is from the air having to go from no movement to movement when the Throttle is open cause’s fuel to come out of suspension. . A diesel has no throttle or fuel in suspension.
Now to the cause of a engine feeling sluggish when a good cylinder head or cam is installed is that boost number, drop as the restriction to air entering the motor drop. More air is going in to the motor, but the reference for the injection system to put fuel in the motor is down. Be it mechanical, or CR the injection system only see boost present.
If you put Zacks head on a total stock motor, it will perform better period, but you must tuned to take advantage of the reduction in restriction of the intake track.
if it has less boost , or restriction , it will call for less fuel
This is not an area where there is any ambiguity , it’s just basic fact.
I thought velocity is what makes turbulence, tumble or swirl stronger inside the cylinder
IMO, as long as people engineer the drafting table designs, these flat runner layouts will not go far too fast. I believe port position is holding diesel intake & exhaust flows back from opimization as far as one part of the higher rpms picture. I see you are keeping Clay Smith's legend going, love it!I have said all along, bolting a performance or ported head on any vehicle is not a "silver bullet" for fixing issues with injectors, timing, cam, incorrect turbos etc
WTF are you talking about? Some engineer wrote it down, that makes it law. LOL
Joe, with all due respect SAE papers are usually written within a narrow scope of intended end uses. Most of the stuff I have read is small variations on production designs or not full-tilt application of new technology but new technology with an emphasis on how to apply it to production vehicles.
What we are trying to do, in most instances, exceeds the limits or is outside of the scope of research. A few of the things that they do not cover is that there are trade-offs with swirl, flow, port volume and cam design. Is swirl, max flow, velocity or low lift flow more important? In my experience, port velocity and good low to mid lift flow trump swirl. Excessive swirl can create restrictions to airflow which can kill power band, cam design can kill power. In other words there are more ways to screw up than do it right.
Heads that flow over 220 or so on the intake usually result in a small loss of low rpm power. Further porting will further exaggerate the issue. A smaller cam that has less lift and duration can help low rpm power with one of these heads, but will kill the higher rpm power.
I believe that at higher rpm, swirl is less of a concern. In this instance mass flow trumps swirl in a MAJOR way. Higher flow will allow the injected fuel to meet more oxygen in a given time than lower flow with much higher swirl. When fuel economy is the primary goal and rpm is lower, you will only have a given amount of air available, swirl will allow the oxygen to meet the fuel faster and give a more efficient burn. I think discussions like this are allowing more people to realize possibilities. I have said all along, bolting a performance or ported head on any vehicle is not a "silver bullet" for fixing issues with injectors, timing, cam, incorrect turbos, head up rear etc.... Most people do not know that they have issues with their tuning.
If that's all you have to add might as well just STFU.
bigger Port volume or better port flow in a diesel has little to do with throttle response. First show me the throttle on a diesel. A better cylinder head is better period. Trying to confuse characteristics of a diesel with that of a gas motor will not work.
In a gas motor the lope or sluggish throttle response is from the air having to go from no movement to movement when the Throttle is open cause’s fuel to come out of suspension. . A diesel has no throttle or fuel in suspension.
Now to the cause of a engine feeling sluggish when a good cylinder head or cam is installed is that boost number, drop as the restriction to air entering the motor drop. More air is going in to the motor, but the reference for the injection system to put fuel in the motor is down. Be it mechanical, or CR the injection system only see boost present.
If you put Zacks head on a total stock motor, it will perform better period, but you must tuned to take advantage of the reduction in restriction of the intake track.
if it has less boost , or restriction , it will call for less fuel
This is not an area where there is any ambiguity , it’s just basic fact.
Zach, in Kawi600's case, do you think that twins with say a 58mm turbo with a diverter valve over a larger turbo would help, what injectors would you recomend, how could he go about raising compression, and what results would you expect, any other recomendations for street use
Im looking at carl's supercharger setup, unless someone can think of a cheaper / easier way to get a cool 650hp with turbos while also having air to burn off the haze on the low end. Truck is a dog off the line.
Ive also thought about the idea of using a bypass to get around a small turbo in a twins or triples set. I guess Id want a pretty small turbo to be pushing some air even at idle speeds.
Wonder what that triple HX35 setup is like?
Most of the 2.6 engines won't tell you what compression their running. The winners in COTPC that I have insight to are most definitely NOT 20:1. I'd argue COTPC are some of the top trucks in the country.deck the piston .030 and the block ,030 is worth about a point and a half in a CR in a 12 valve depends on the piston, is about a point.
most of the thoughtfull 2.6 engines out there are knocking on the door of 20 to 1.