+1

This is exactly where I sit with the issue right now.

 

There was a shop here in the PHX area that put on the cosworth head on their subaru and made something like 30 or 40 hp more with no tuning or any other change...just direct swap. But this was a built scooby to begin with.

 

I once installed low restriction muffers on a '71 Z28 and made almost 50 more hp with no additional tuning, but that doesn't apply to us either.

 

They are a very good head. They have a big price tag due to the high quality work that goes into them. As soon as I save my pennies I will be running one on my personal vehicle.

Just so we are all on the same page here is a list of the spec of the head.

• CNC Ported/Machined finish port- New Castings
• Hand blended finish work
• Intake –20% (max) increased flow
• Exhaust – 22% (max) increased flow
• 4-angle Inlet Valve job
• 3-angle & radius Exhaust Valve job
• Valves are lapped
• Back-Cut Inlet Valves
• Heads are Ultra Sonic cleaned prior to assembly
• Heads are Serialized and sport a machined Cosworth logo
• +1mm Stainless Steel Intake Valves (1800 degrees max.)
• +1mm Inconel Exhaust Valves (2400 degrees max.)
• Performance Valve Springs
• Titanium Retainers
• Hardened Steel Spring Platforms
• Knife edged port divider

these heads are a racers dream. When I get mine I will dyno it for you guys but for now I will continue to drool.

 

Are you comparing the price of porting an existing head to the price of purchasing an entirely new one from Cosworth? How much does Mitsubishi charge for a spare head? Regardless, if I had the cash, I'd take Cosworth engineering over a tuner shop tech with a rotary tool and a promise.

 

Being that you're a vendor and a dealer for this item, you might also want to mention the fact that you won't exactly be facing the same $3849 pricetag as 99+% of whomever else follows this discussion.

 

looks like i wont be buying a coszy head

 

Trust me the discount isn't amazing for even WD dealers such as us. Another problem is since I buy it from Rallysport I have to pay Utah sales tax(6.6%) so it will be pretty close to a wash with shipping when all said and done.

Plus being a vendor we deal with many shops that I could have my own head ported and install my own valvetrain and probably save even more money but the quality that goes into them is enough for me to spend the extra money on it.

 

What's the difference between a very good condition reman'ed head with 20k miles on it and a brand new one? The answer would be nothing, not if your using a reputable machine shop. Considering the fact that both would be ported/polished, etc. the difference between the two (if there was any) would go down even more.

Would anyone in their right mind buy a new head from Mitsubishi when good spares are available at half the price? Evo's, unfortunately, are being wreck and stolen everyday. In fact there is a stolen/recovered EVO 8 sitting at a dealership not to far from me currently with a good engine. Why wouldn't I just buy that one if I wanted a spare? Even If I did have a spare, what would you do with it? You can only put one head on one block, so the spare becomes something else to store in your garage.

If you don't have a clue and know what to look for or ask for when you take your head to a machine shop then I agree, the Cosworth head may be a better deal for you.

 

You do not need to keep the spare head you could sell it if you wish. I believe the main reason they start with a new blank is that alot of people could not package a head properly and also could send them a warpped head.

Then to resurface the head to make sure it installs properly(more labor and more money that customer may not want/be able to pay) or them getting a damaged head and dealing with shipping insurance would be a nightmare.

I think it is a great option to get your head ported by a good machine shop that is local to you and you trust but it will never be as perfect as a CNC head and most facilities do not have the ability to flow test different heads and see what works the best as cosworth does.

They did not just do one head and say I think this will work they most likely went through a bunch of heads looking for that extra percent of flow to give them the edge over the competition.

 

I don't think anyone is debating the quality of work. The port work looks pretty good even though the flow numbers they give you are absolutely meaningless.

To me if I am going to need to see before and after dyno numbers against another well known and reputable shops (ie Polk Performance, Forrester, etc.) ported head at the same price range.

If I'm going to spend as much as Cosworth is asking I should at least get nitried and sodium filled hollow stem valves, bronze/magnesium valve guides, and coated springs which are not included. Instead what you get are middle of the road valves.

 

One of the biggest fun questions I always have with regards to porting heads is why, and how much.

Having somebody run one of these said Cosworth heads speaks tons especially if they can point to what the differences are with relation to a stock head. Flow rates are a nice solid indicator, but flow rates are a fairly static measurement that sometimes leaves me confused with relation to dynamic airflow transients that are going on in a motor. I've seen indicators of some nice gains by actually restricting port size, but optimizing the surface quality of the port.

So my question now is, who has run a Cosworth head, and why did they want to run a Cosworth head? If I missed a post here, please point me back to it.

Cheers,

~j.

 

in my opinion cosworth heads are extremely high quality... You dont have to worry about anything when it comes to the head. to say that the cosworth head has "middle of the road valves" is ridiculous. you can bolt the head on and go without having to worry about dropping a valve. If you dont want to spend the 3800 bones to get one, then DONT. Dont sit around and try to bash it because you think it is overpriced. those of us who were willing to pay for it will enjoy not having to worry about it.

I am sure there are other heads out there that are built for half the price that do just as well, and if you are lucky enough to find one than good for you. but honestly who cares about the monetary argument. buy the head if it fancies you...dont buy it if it dosen't.

quit 'cher *****in' already.

 

1. How do you restrict port sizes?
2. What do you mean by "optimizing" surface quality?
3. You have seen? or do you have actual data of the gains? How did you record the data?
4. What type of gains were realized?

 

Many people think that because something is from a big name and cost a lot it has to be the best. If those people like to throw their cash around like that then that's their business, but those people shouldn't try to enter arguments when they don't have a clue as to why the product is better or inferior. If you can't look at the valves and the description of why I called them middle of the road and not understand then you really don't have much to add here unless your contributing dyno info which you are not. Theory as to why it is better would be better than some clueless rant.

This isn't a thread on why you think it is fairly priced or not it is about results.