So Ted, I think he still wants to know how much Cossie spends on R&D for there heads and how much JAM spends, and how much power difference there is.

Scorke

 

They do none of the above. They are a machine shop.

 

Budweiser spends more than Sam Adams, so what does that mean? Bigger companies spend more to do less, and spending more doesn't guarantee a better product (General Business 101).

I've stated my opinion, explained how it came to be what it is, and have nothing more to add.

 

I do know that JAM does there own CNC work, and flow testing, (I've seen their machines in person). JAM has been doing 4G63 heads much longer than Cosworth (that is a fact), they built the engine for the first 8 second 4G63 AWD Talon. They have been building 4G63's since the early 90's. If you really want to know the specifics of their equipment, why don't you call them? JAM is the best 4G63 machine shop in the US.

 

Hello UB,
You have seen our work at Mohammads, none better! When we "Balance and Blue-print" an engine it is ready for use. And our cylinder head packages are the same way. We offer several different packages so we can offer the correct one for your build the very first time around. Our EVO Stage III and Stage IV packages have all the right components already installed for your camshaft upgrades. We use a super strong dual valve spring that is designed for the higher ramped cams, we actually machine our heads in order to use these springs. Unlike the smaller drop in dual springs out there these babies hold up no matter what we have thrown at them. The improved airflow is also second to none, our Stage IV packages have +18% airflow increase. Our customers make more HP at lower boost levels due to the increased airflow efficancy. It's all about the Quality! of performance.

 

I spoke to Carmela at JAM, here is what she had to say about the whole Cosworth vs JAM stage IV argument:

"Yes, we have tested the Cosworth heads here and ours did out flow them, plus we actually use a better-stronger valve spring and higher flowing valves, and our deck surface is machined to a extremely smooth RA50+ finish and we final wash our heads so it is not full of metal up inside the ports."

Having seen there head work first hand, I have no doubts in my mind that these claims are true. These guys really know their stuff.

 

Are they comparing their Stage IV head against the Cosworth?

 

Well, that should settle it. If one of the manufacturers says their product is better (with no facts for any independent analysis), why should anyone doubt it? They have no financial stake in the outcome, do they? .... Oh, I guess they do

I called the NAPA machine ship here in my little town. They said their head mods were better than JAM. That should top what you were told, since we're taking everyone at their word without any data. Just send your $3000 to me, and I'll have them send you a modified head pronto.

 

The test to which I referred with the JAM head was independently, competently conducted.

FYI

 

Who conducted the test?
What data did they collect? Flow only? Flow, lift and port velocity?
Under what parameters? On a running car, or on a constant velocity flow bench? What was the diameter of the shrouding cylinders?
Who paid them?
Where's the data?

You know that these questions are basic to evaluation of the claimed results. Port velocity is critical to making power. Flow is not the end of the story.

I'm not knocking JAM. I have no data to compare. Buschur post the flow numbers for his Stage III head, and they're higher than the 18% that was mentioned for the JAM head in this thread. Does that necessarily mean that the Buschur head is superior? Not necessarily. So do the numbers for the Cosworth, as I recall. I do remember that the Cosworth head was on the AMS 1000HP Evo, which suggests that it flows enough for high HP cars of pretty much any variety. I confirmed that it's also on their current record setting Evo, which looks to be making more than 1000HP by the E.T and MPH numbers it's putting down.

The test you reference by JAM of their head versus the Cosworth may have been a valid comparison. It may not have been. It may be deficient in what data was collected, or in the manner the testing was done. We simply don't know, and until the data is presented, it's just opinion. If it's on a bench, instead of on a car, it has inherent limitations.

"Everyone is entitled to their own opinion, but not their own facts".

 

Someone correct me if I'm wrong here, but JAM cylinder heads are ported by hand like most others, correct? I believe Cosworth are the only ones who offer CNC'd heads for the 4G63...

 

Cosworth hands down...

 

jam ,is gr8 .ive personaly seen there short block and it looks awsome .
ill be goin wid jam soon ,
but cool down guyz .

 

Consider yourself corrected. The JAM and ISP heads are CNC ported, and I know of at least one other (a private offering).

 

The data included flow and lift at a fixed depression, was conducted by the same individual, on the same bench, back-to-back, without any 'fine print'. The shrouding cylinders were approximately the stock bore diameter. The individual who conducted the test ports heads professionally (for a different application), owns his own Superflow flow bench (and shop), has no financial interest in the matter, and was purely interested in making a fair comparison for his own interest. He is not a member of this forum, and the results were not posted here.


In the 25 years that I've been active in this subject, you might consider the fact that I know a little more than you think. Have you questioned the data generated by Cosworth in their published 'test graph'? Hmmmmm. . .