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Hi all,

This is not for the feint hearted

I'm looking at some FI porting on a hi-port 1.8 head.

What is needed is investors willing to contributr to the $90 p/h R&D cost.

The ball park I'm aiming for is an increase from 145 cfm to ~250 cfm

The R&D will be done at Speedworks in Ringwood and for 10 hrs of developement we should obtain this increase. Speedworks has a state of the art flow bench and heaps of experience with high quality flowing and porting (call Tony De Sensi 98760600 or call in, he's just down the road from the MX5 Factory at 1/12 Molan St Ringwood)

Although personally I'm looking at FI, without a doubt the NA guys amongst us will also find this attractive.

I have a sacrificial head that I'm donating to the cause along with 5 hours of R&D, all we need is a few more people to throw in for the additional R&D.

All contributors ($90 shares) will get full access to the dimensions and modified areas.

Either PM or post here if you're interested in getting the most from your BP

Cheers
Bazz (Wòó)

Sorry maybe didn't explain it clearly (could be why no takers yet lol)

Porting can be done a few different ways. Usually we match the head port size to be slightly 0.25mm smaller than the gasket opening on the exhaust AND 0.25mm bigger than the gasket on the intake. This ensures that the flow is always from a small cross sectional area to a slightly bigger cross sectional area.
This principle is applied to both the complete inlet and exhaust paths.

Then there is chamber porting. This consists of adjusting the valve seats so that they dont inpede air flow when closed. So thats area 1. The second area is the surface of the chamber and the actual runners, smooth is bad but casting marks are worse. This is where most people take their porting too. It will gain a 60% improvement in flow if you recess the guides and open the runners to induce " Laminar Flow " (area 3). This is called pocket porting

Then we get into the serious stuff
Chamber design is usually intrinsic to the mould that the head has been cast into. The best performance chambers are (and I stress I'm not an expert in this) pent roof chambers. If the head has enough metal then you can turn our head into a pent roof chamber. Another important area is the quench zone which is the flat area around the sides of the chamber that do the final squeeze right at TDC.

The reason we can build a head and do mild porting (areas 1,2,3) is because if you overcut or undercut these areas it doesnt make a lot of difference to the performance. This will cost about $1000 and will give about a 60% improvement in flow.

To get the other 40% (up to its maximum) will cost money for the Research and Developement
The person in Melbourne with the best reputation for getting the maximum is Tony at Speedworks.
Using an old head he will grind and fill and flow till he gets to the 100%
His cost is $90 per hour and has quoted me 10 hours of R&D to do the deed

Dollar wise I'm strapped, the reason is that like you once the R&D is done we still have to replicate his changes to our heads which will cost the $1000. Only difference is this time we know that the changes being made are actually going to give us the edge, power wise.

I'm donating my old head to be sacrificed to do the initial testing (ie cut up with a band saw and ground, filled and flowed) and will also put in 5 hours of R&D

so straight up there is $500 worth of R&D. With another $500 the pattern will be complete and the information will be available to anyone that wants to pay for it.

You could do this R&D yourself (or your head guy could) but it would cost you $1000 plus the $1000 to do your own head (you have to pay that anyway). Doing it this way we all get the result for $90.
$90 vs $1000 ...... I know what I would choose.

I hope that made the situation a bit clearer. It is quite complicated work, but the savings are big if we pool together.

Cheers
Woo

I dunno if you'll get many bites, but all sounds exciting.

Perhaps another approach would be to a group buy style arrangement, where Tony promises to develop and build an MX-5 head for X amount each for the first 5 people? (obviously specs would need to be provided)

i would love to help out but the current motor build is a mild..ish NA so its a little over kill for me at the moment.. when i build a race motor id be keen but that wont be till next year sorry

Okibi wrote:I dunno if you'll get many bites, but all sounds exciting.

Perhaps another approach would be to a group buy style arrangement, where Tony promises to develop and build an MX-5 head for X amount each for the first 5 people? (obviously specs would need to be provided)

Mmmm I thought that was what was on offer I'm not doing well am I

Summing up the group buy

Your normal cost for porting and fitting OS valves would be >$1000 so for ~$1100 you would not only get the machining work done BUT you also get 10 Hrs of flow testing and developement (normally $90 ph)
You supply the stock hi-port head, your choice of valves, springs, seals (that way you get what you want size wise)
Tony will then fit new Serdi seats to your valves, port and flow your head using the results from the R&D
Your head will then be flow tested to confirm the porting results.

So the cost to you is about $1100 to achieve a flow increase from 145cfm to 250cfm

This offer is only available if we get 10 people interested. Work has started so we need confirmed takers asap

I'll start the ball rolling: (each place is 1 hr of R&D, $90)

Head for developement: Woo
1. Woo
2. Woo
3. Woo
4. Woo
5. Woo
6.
7.
8.
9.
10.


Note: This developement is only applicable to the hi-port 1.8 lt (NB8)

irwin83r wrote:i would love to help out but the current motor build is a mild..ish NA so its a little over kill for me at the moment.. when i build a race motor id be keen but that wont be till next year sorry

If your going to do any head work Irwin83r then your going to spend $1000 + anyway. The results will be ok, but for an additional $90 the results could be stunning.

Food for thought

Don't know if you'll get anyone up front. Maybe if you prove a good setup first, then people will be willing to pay a little extra to get the same job done on their own car? But aiming for a >70% flow increase is pretty optimistic.

The requirements for really good porting jobs are essentially limited to the racing community, and then people are generally not willing to share, already have their own guy, or already (think they) know what they're doing. And not many are in Melbourne. $1000 goes a long way to a turbo kit, and then the need for porting is much reduced.

Not to mention that you've got at least 5 different versions of B6/BP MX-5 heads to deal with, plus the requirements for everyone will be unique (combination of cams, compression, overbore, intake system, exhaust system, competition rules, reliability, valve size, ........)

BTW the MX already has a pent-roof head.

i would definatelly be up for it.
the only problem is its totally unpractable for a street car.
if i had a race car then i'll be in like a flash...
(i dont have an aftermarket ecu, intake, exhaust ect.)

i think if you going to build something like that then you'll need a good ecu, quad port intake, good pistions ect.

so its not really $90, its more of a 5k engine build which is definatelly out of the question for us mortals
and even if we did build a 5k engine i highly doubt it would be anywhere near good for the streets
so having a high flow ported engine would do us no good

[quote=
so its not really $90, its more of a 5k engine build which is definatelly out of the question for us mortals
and even if we did build a 5k engine i highly doubt it would be anywhere near good for the streets
so having a high flow ported engine would do us no good[/quote]

As one who has been using a similar engine on the street for the last 4 or five years, it is not that much of a problem, unless your SO uses it .

As a dual purpose car, you must accept a certain loss of tractibility, but unless you are building a full-on no compromises racecar, it is certainly feasible. For example, the SO and I spent two weeks touring Tassie (with 14 or so other MX5s from here) with no problems, not even a speeding ticket

Group buy is now closed

Head for developement: Woo
1. Woo
2. Woo
3. Woo
4. Woo
5. Woo
6. Woo
7. Woo
8. Woo
9. Woo
10. Woo

The head is finished and the results were better than expected

The detailed specs are now available for sale. PM for details.

Thanks

Congrats Woo, I thought those figures were ambitious but it must be awesome to prove that wrong !