Ok I've been doing some reading as I see a few guys chasing the MIVEC option (and frankly I still don't even know how Mivec works apart from likening it to VTEC) and I never really got very involved in those locked threads from 5-6 years ago. I read that BOX put NA into his car and then pulled them again, some guys say they are better and some argue. I'm over the argue bit. Why am I interested in all this?? Because I have  two GTO's one of which is a dedicated racer, and I have about 10 useful years left in me to continue the development of that car.

One thing that I thought I did raise years ago when this debate raged was that of the crucial, fundamental difference between the TT and the NA. That is of course the Sucking vs Blowing (mmm this sounds a little dodgy!!) or Vacuum vs Pressure. 

So my thoughts are this. Why would the great developer of these cars make two different parts when one was supposedly superior (NA) AND wouldn't the same logic apply to the Gentlemans agreement at 205Kw - being that the TT head port design was dumbed down ( by this I mean why change the head when they already put a 2 cent  plastic restrictor in the Wastegate Solenoid at factory to restrict the boost level). I am no engine expert, and no Engineering expert! But fundamentally there is a major difference in intake characteristic here.

So the purpose of this post is to kindly ask anybody reading this to let me know if the differences between boosted and NA applications on the design and efficiency of the ports are discussed anywhere either on this web site forum or any other. I want to do some more reading if there's any to be done on that specific item. It's hard to try and fossick through the posts on the search engine of this forum (and others) but if anybody can help me with this analysis/discussion I would be greatful.

You may point out that why bother with this quest when the MIVEC option appears to outweigh any benefit of NA? (Based on Mitsi designing the EVO 9 &10 with Turbo'd MIVEC heads). The answer like me is simple- One thing at a time please! I don't want to battle the MIVEC learning curve yet.

And again, Like I said at the time way back then - Why not just ask the Mitsubishi Engineers that designed these items? After all they must still be alive and will enjoy the memory of their craft...

Why do you keep asking though?

Just go do it?
Or don't bother.
Waste of time asking a bunch of kids on a forum.

There IS no debate.
Those who've used both sorts of head KNOW.

Those who haven't DON'T KNOW.
Never will.

viewtopic.php?f=9&t=4342



Maybe I should give you a bit of a clue to ease your suffering?


Going back to about 2003 there used to be a place called "speedtech".
It was run by a bloke by the name of Andre.
I had an engine in there in pieces and I still remember him looking at one of the heads and saying...........you wouldn't want to use those for a race engine.That's what made me have a look at N/A heads.
2 years later it was still there and I was just a bit pissed off.........It had to pay a lot of money to take it away in pieces.
Instead of blowing up peoples engines, he now teaches people how to blow up their own engines.

The next engine I built had N/A heads on it.
Then I moved onto mivec as it's by far the best.
I can quite confidently say I won't be building another engine with TT heads unless it's for someone else or for getting data from for myself.


BTW evo9 isn't  original mivec, it's VVT.
On the intake cam only.
It uses a fancy mechanism on the cam gear controlled by oil pressure. It's just a normal cam but it's phase is changed with respect to the crank .
The mivec part is just for marketing purposes so people think they're getting technology from the Dakar rally when they're not.

The 6G75 mivec is a totally different system again.....SOHC and only on the intake.

Sucking or blowing doesn't factor into anything.......they all suck but with a different pressure differential.
Boost increases air density.
Density changes the way in which it flows.


As far as the cams go, GTOs use different cams from the 3KGT.
There's not a lot of difference between TT and N/A cams but the N/A ones have a bit more duration, so bette for top end breathing.
The 1st gen cams have more lift so they're the ones to go for.
All the aftermarket cams are ground wrong, they all copy off each other and the way they're ground wrong makes one bank have a different profile from the other bank........kelfords included....all lemons.

magn1t wrote:

Why do you keep asking though?

Because I'm looking at all sorts of options and this is one option. And my general level of comprehension of this type of item is lower than many experts like you Steve. And it is interesting.

That TT divider is thick and heavy and must provide more strength in my Op. And the little eyelids cast in before the Injectors!! Wtf are they for? Seems to be a lot of people don't talk about pressure, they talk about flow or speed. But in my head surely much higher pressure means less speed of the flow.
In any NA engine it's all about getting the thing to flow from intake to exh. In a Turbo it's all about getting pressurised charge into the cylinder and dealing with getting it out again.
So the difference is the pressure differential right at the junction of high pressure(density) and vacuum. That would be the valve opening and close to it maybe back out to the nose of the divider?

BATOOH wrote:

That TT divider is thick and heavy and must provide more strength in my Op. And the little eyelids cast in before the Injectors!! Wtf are they for? Seems to be a lot of people don't talk about pressure, they talk about flow or speed. But in my head surely much higher pressure means less speed of the flow.
In any NA engine it's all about getting the thing to flow from intake to exh. In a Turbo it's all about getting pressurised charge into the cylinder and dealing with getting it out again.
So the difference is the pressure differential right at the junction of high pressure(density) and vacuum. That would be the valve opening and close to it maybe back out to the nose of the divider?

The thick divider cant do anything other than disrupt the flow.
The little eyelid things, again they'll disrupt the flow, probably to help the fuel and air mix a bit better.They're just downstream of the injector.
Lots of people talk about pressure flow and speed......lots of people talk lots of sh** too because they've got an opinion which they like to express but they've got no idea.
The air flows in waves in an engine, not with a flow bench. 
With a wave, the pressure density and flow are constantly changing with time. It's a form of stored energy which is important.
If you want to break it down to "average speed" then it's proportional to RPM, nothing else."Average density".(goes with pressure).......that's proportional to the throttle position. At idle, the density is about 1/3 atmospheric, full throttle, approx atmospheric then if you've got a turbo, it's more. If it's running 1 bar boost then density might be double atmospheric.
BUT
Boost is just a measure of restriction to the flow so a better flowing engine will make more power with less boost.
Or if you want to compare a 30M to a TT they both make close to the same power but the 30M does it without boost, the TT needs 0.5 bar boost.




But...this is just repeating and repeating and repeating...........
Lots of interesting threads on 3SI.
If you read enough you get tell who the compulsive liars are.

Some bloke was bragging how he was going to make 800HP on stock heads.
Here
http://www.3si.org/forum/f1/difference- ... ndex2.html
He did of course because he had his own dyno. No, it wasn't with TT heads.
That was back in about 2009
http://www.3si.org/forum/f35/n-head-dif ... ad-276617/
not that one? Post no 8  has some nice photos though.

http://www.3si.org/forum/f1/turbo-vs-no ... ed-525523/

no, not that one..

Turbo head has larger ports?
No it doesn't.



Hang on a minute?
Now why doesn't someone ask...............how do you measure them?
Who determined that?
And how did they do it?

I think they're all crackheads or on acid or something...........I just looked at them and they're bigger?







See what I mean about everyone having an opinion.
How big are the ports?
I'm the only one who's actually measured them.....it's on one of my tech threads....see below.


http://www.3si.org/forum/f36/ported-3-5-heads-545818/

That's a bit more informative because it's got numbers.Reading on a bit more, they might be hyundai / kia copies, could be same or different, need casting marks for ID.
The Pajero 3.5 heads are the 3A casting which has the small intake ports. They're nicely shaped so make good numbers on a flowbench but they'll never make more power on an engine than a N/A 3N head..........because flowbench numbers don't work.

You've been lied to.


From those links.....someone keeps mentioning combustion chambers being different, comes up all the time too. The combustion chambers are all the same at 46cc. There's always someone who wants to say that they're different.
Then back to the intake ports, how big are they really?
The valve positioning is the same, the mounting flange is the same for the lower IM, so the length is the same. So the volume corresponds to the average CSA. or at least lets you know which has tight spots which are obvious anyway just by looking.
 3A (3.5 head) 107.5 cc
30M are 126 cc
3N is 130 cc
3T is 129 cc.


So maybe someone can explain how a 3T intake port is actually bigger than a 3N intake port when they've done zero measuring. Not that bigger is better because it's not, it's the shape that's important.

It's NOT bigger of course, it's just more bullshit from clueless kids who've got no idea who like to express some sort of worthless opinion.


It's actually a really good example of how dangerous religion is and how it starts wars.
Because that's how religion gets spread..........eg, the likes of ravensierra who's got no clues, never put an engine together but want's to make out like it's the other way around but likes to argue just for the sake of it........crackhead?


Maybe the best thing you can do, there's a bloke advertising on TM under services, he's got a flowbench does head porting in Chch.
Go see him, ask for an unbiased opinion. 
So long as he's got several years experience behind him, should make a bit of sense.

https://www.trademe.co.nz/services/trad ... 263630.htm

Take a TT head to him as well as a N/A head. pay him some $$$$$$ 
Come back on here with some numbers?


This thread here must surely take the cake?

http://www.3si.org/forum/f4/tt-heads-complete-259050/

You've got to log in to read it but it's mr Import performance who made 800HP with stock heads and cams selling his newly acquired but unused TT heads because the N/A ones on his racecar look better so he's putting them back on......in 2005.....talk about deliberately telling porkies in order to put everyone else on the wrong track and at the same time make lots of money selling inferior products. Well no not quite. All the posts deliberately say stock heads and stock cams. Not stock TT heads as you'd expect.It's all in the wording.

Quote from ravensierra......

Next, you have your tinfoil hat firmly in position Barry if you truly believe that the shops, the tuners and the respected members of the 3S community are all systematically lying about the turbo heads flowing better than N/A, to somehow fill out their wallets.



This here is worth a read too.

About cams...seeing that a lot of records have been set with stock cams......

http://www.3si.org/forum/f1/cam-talk-565529/

The answer to the problem is on posts 33, 34 and 35.
The cam profiles for the 2 banks are the same.
But the banks are mirror images, the finger followers run on opposite sides.
Which means that to get the same valve lift profile, you need a different cam lobe profile for each bank.
Wouldn't you expect the cam gurus to know that?....surely.
It's easily measured with a dial gauge.

magn1t wrote:

This here is worth a read too.

About cams...seeing that a lot of records have been set with stock cams......

http://www.3si.org/forum/f1/cam-talk-565529/

The answer to the problem is on posts 33, 34 and 35.
The cam profiles for the 2 banks are the same.
But the banks are mirror images, the finger followers run on opposite sides.
Which means that to get the same valve lift profile, you need a different cam lobe profile for each bank.
Wouldn't you expect the cam gurus to know that?....surely.
It's easily measured with a dial gauge.

I read these posts and a little of the start of the thread. I'm surprised, as you are alerting me to the fact that there are different cams for font and rear banks on our 6G72 TT, whether the cams are stock or not! Are the cams marked front or rear or anything else. I guess it's hard to mix up the intake cams on a Gen 1 because of the Cam angle sensor. But can you mix up an Exhaust cam on this engine?

The front and rear banks are physically different.
The only possible mix up is with the front exhaust and front intake cams.

The point is that the front intake cam is ground with a different lobe profile to the rear intake cam.
The front exhaust cam is ground with a different lobe profile to the rear exhaust cam.
That's done to ensure that the valve lift profiles end up the same.
Due to the rockers running on the opposite side of the lobe.

The cam grinding companies should have been aware of this 15 years ago but they still fecked them all up.
Kelfords included.


These clowns like to bring up the old "shaving the block or head " problem.........a decoy.
It makes a difference of about 0.5 crank degrees on the rear bank.
Then there's those other idiots who like to think they can adjust the cams on the dyno?
4 of them.........lol


That thread on 3SI, it points out many problems with aftermarket parts.

Aftermarket EFI fuel line is unfit for purpose and potentially lethal, as I mentioned in my pump and FPR tech thread.
Why would you replace injectors when they're easy to flow test and clean?
Cam gears don't zero at zero.
Cams are all different , there's a variable error in the indexing.
The lobes are ground the same when they should be different for each bank.
It's a 2013 post but it's a 2004 problem, known about in 2004.
You pay a boy to do a man's job and you end up getting a boy's job done.


But anyway, if you make the effort to read all 33 pages, it's all explained.

Like post no 116 shows the cam doctor.
If you study it carefully.......there's a roller running on the top of the cam.
That's OK for a pushrod V8 or similar but a rocker arm moves in an arc so the geometry is different.
Not much at all different but still different which reminds me..........when I rang kelfords all those years ago and told them they f***ed my cams up.......the reply was.......they must be OK because the cam doctor says they are.....lol.
Cam doctor tells lies.
It's the wrong tool for the job.
My study of geometry at school says so.

Nobody has seen this vid on ewetube?

Nor me until now, it came up by accident.

https://www.youtube.com/watch?v=tGiTmBrxMu0


The best part.........not what you thought huh?
So from that it's general concensus that the TT ports are far bigger than the N/A ports?
By eye because that's all you need?



Now lets say you were a professional head porter, they talk about terms like SSR and MCSA.
You can google them.
A good head doesn't really want a MCSA (constant is better) but a 3A head does.
SSR, well if it's too tight it needs filling. Ports are often filled with epoxy where the shape is wrong.......makes the SSR bigger so you don't get dead spots and whirlpools.Bigger isn't better when the shape is wrong.
The TT head is all wrong, the floor needs filling in the middle to direct air more towards the valves..........
Meanwhile over in France (no wonder they lost the war).......

https://www.youtube.com/watch?v=nT4noQRQR2Q&t=154s

Then think about all the time and effort you've wasted when you've still got that really crappy intake manifold which nobody ever gets rid of.......not quite everyone........because nobody does a mass produced one which you can BUY. It's the very worst part for performance that's on the engine.
Then to throw another spanner in the works, mr froggy has 1 mm bigger valves.It's the port size that determines the flow not the valve size. The valve just blocks the hole. So the seat has to be cut which requires a seat cutting tool which is at the machine shop.You can't do the job at home. Sure you can fit bigger valves to standard seat butnot properly and anyone who does that clearly doesn't know WTF they're doing. All the valve geometry and specs are covered in the workshop manual which everyone has read as a free download?





No, I just made it all up as per normal.

magn1t wrote:

Nobody has seen this vid on ewetube?

Nor me until now, it came up by accident.

https://www.youtube.com/watch?v=tGiTmBrxMu0

The TT head is all wrong, the floor needs filling in the middle to direct air more towards the valves.........
No, I just made it all up as per normal.

The really Interesting thing here is that 3SX have the greatest Motivation to prove a point then sell a performance increase..
Succinctly, 3SX have done this specifically for the NA platform by providing DYNO graphs of performance gains of their bolt on Exhaust Intake upgrades BUT have not been able to reap any gains hence reward for the TT platform (of a similar nature to the NA as displayed on their website).
Sure it will be argued that the TT platform is different and there are plenty of turbo upgrades, a high flow downpipe etc, (yes Ported and Polished heads for both Platforms) But by Dint of Omission, from the avowed experts, there is no gain to be had by altering the Intake and exhaust characteristics of the OEM TT head using bolt ons. However,  Steve, you differ by saying that the TT head is all wrong... 
Well I am of the opinion (at this moment of time) that the TT OEM heads were designed properly and that they function best for TT platform.

I wouldn't expect any other opinion.


BTW do you know how 3SX actually made the numbers with their N/A upgrades?
I watched the videos and asked the appropriate question.

It's easy. They did the baseline runs with a pod filter and the bonnet closed.(sucks hot air , makes less power)

The "upgraded" runs were done with the bonnet open.


You won't find the vids on their site now.....they removed them after questions were asked.
If you can find them...prove me wrong by posting the appropriate links.


A dyno is a tuning tool and there's lots of ways to cheat.

To be scientific about it , all runs should be done in the way in which the car is driven, that's with the bonnet closed. It shows up problems you won't find with the bonnet open.......like pod filters losing power from a stock air box.
Dynoing a car with the bonnet open then driving it with the bonnet closed....well it just doesn't make sense......does it?
If you're going to make videos to sell parts then at least don't get caught cheating by accident.
Or rather , don't get accidentally caught cheating.


3SX probably don't sell many parts these days anyway. They're 25+ years old now, most of the cars have blown up and the market is flooded with crap aftermarket parts that don't perform.

This debate can only be settled one way, and as yet nobody (to my knowledge) has done a back-to-back comparison with an engine dyno.  I get what Steve is saying, which is why I'm intrigued.  Just not intrigued enough to build an engine dyno and go through the labour of testing two sets of heads.

I reckon 3sx have already done what you suggest and dyno'd the two and concluded no appreciable gain or possibly a Loss. Anyway I don't think it's an argument. It's more an understanding of beliefs. My view is not one of flow. My view is one of pressurised charge sitting right up against the Intake valves and all round them. Thats why the floor as Steve says is too deep. The amount of pressurised charge in the immediate location of the intake valves must be sufficient so as too provide the maximum and fastest expansion when the valves start opening. If you had only a little pressurised charge waiting to go in, the maximum benefit of the process wouldn't be as great.. I will email 3sx soon anyway. BTW do you know of that guy Stalker who parts out GTO's in Aussie??

BATOOH wrote:

BTW do you know of that guy Stalker who parts out GTO's in Aussie??

Yeah I've got some things off him already.  The community is a bit different over here, nothing is cheap.

reply from 3SX.....

Morning, and thanks for the message. All I can offer is this: Due to the port design, the NA heads can only really benefit the turbo cars if the intake ports are opened up,and larger diameter turbo valves are added. We sometimes convert NA cores into our Stage 3 heads for the turbo cars if there are no TT cores available. There are larger turbo manifolds for the TT cars, but they need to be matched up the a corresponding sized turbo to get the most benefit, as with adding a matching downpipe, etc...Balance is key

I did not have sexual relations with that woman.........same meaning, just different words.

https://www.youtube.com/watch?v=VBe_guezGGc

These allegations are false.


Maybe you need reminding once more that IPO claims the turbo FWD records, the ET numbers are nowhere near as important as the MPH numbers...............claimed to be done with stock heads and stock cams.
The MPH relates to the average power made while the ET relates more to the hook up.
It might actually sink in one day?
Still unbeaten too.








Can't swallow all the evidence?