Feeler - 65mm or Bigger Billet T-Body
 

Hello,

John and I at M-Tuned.com have been talking about producing a Billet T-Body for the Mazda Miata. Probably start with a 1.8 version around 65mm. We plan on making the throttle a direct replacement which will use your Miata TPS and IAC sensors.

This items would be made out of a big chunk of Aluminum and would be a very trick piece. It has been proven time and time again in the Honda world that a large T-Body works wonders on a Turbo engine, and I am starting to see others playing with smoothing out the lips and ridges on their T-Bodys.

Would you be interested in this type of aftermarket piece? It would probably retail for $249-299.

Remember... Our T-Bodies are very small! 65mm would be a large increase in size.

I'd very likely be down for this

Although not at the top of my list of priorities at the moment, I would definitely be interested in this in the near future.

id go for one if i wouldnt be selling my car...

Id like to see Dyno charts. If 10 or more horsepower though out the range is possible, ill be interested.

Marc, I'd be down but would like to see some proof. Got any Honduh before and afters to share?

I'd be down, but im cheap, so I'll never actually buy one. But i would love to have a bigger TB with a working idle valve.

Marc, I think this would be a great product but I doubt very many will sell, simply because we are all cheap bastards. I am sure you would sell a few, but the FI miata community loves to stay in the low boost range where you will not see any significant gains from such a mod as tb and/or bigger intake manifold.

I would probably go with one myself when the time comes, but I would pair it with a properly sized manifold and a built head, so it would really be a must have for me as the stock tb would be a restriction at that point in the power level I want to be at.

Definitively something you should carry I think, even if you only sell 20-30 per year.

Even though the price is very reasonable for a CNCd piece, I'd like to see it lower if at all possible. To state the obvious, many more people would be in on this if the price was much more affordable, lets say $150ish would be freaking awesome and I'd go for one sooner lol.
I think that you should be able to offer the same tb with a FM-type of spacer adapter for the 1.6 cars as well, and give them the option of having a 1.8 tps for their MS....just a thought.

I'll take one. Let me know when it's ready, I have money in hand. I've wanted a larger TB for a long time but can't seem to find one. Considering on a MSM, at 10-12 PSI the factory TB inlet pipe swells and blows off, I think there is some restriction there.

This is my main concern. A larger TB will confuse the IAC.

It doesnt seem to do this in other applications, why the miata?...not poking at you or anything, just wondering why you think this would be the case.

I wanted to buy a intake manifold from Begi, so I sent him an email on sunday and chatted with him a bit. Said that the popular 75mm throttle body would confuse the IAC requiring some sort of adapter.

I dont know if this will confuse the IAC with a standalone, but I can see why it would throw off the factory computer if running parallel.

i don't know why the IAC would even matter. it leaks air around the closed throttle plate. who cares how big the plate is?

The IAC bypasses x ammount of air when the throttle plate is closed, why would it matter what the diameter of the tb is when the only air that gets bipass is going through before the throttle plate...once the plate is open, the IAC is pretty much not doing anything, it could care less how big the plate behind the IAC inlet is, it just doesn't matter.
As long as the IAC inlet is the same as on the OEM tb, we should not have a difference in idle, and I think that is what Marc meant when he stated that we will reuse OEM TPS and IAC.
Please feel free to correct me if I'm wrong, but I reall don't see this as being all that complicated. All you are changing is the diameter of the tb opening, not the IAC vane geometry.

I'm down if gains are proven to be significant....and all screws inside the throttle body are very secure. :giggle:

hardy har har har.

I don't see why everyone wants to see dyno graphs etc., it is comon knowledge in the tuning world that a bigger tb unleashes more power, it doesn't make it, but a 50mm tb is a restriction and by increasing the diameter and therefore flow, you will see gains, esp. on the top end. I don't care for any dyno graphs to show comparison between this and the stocker, I realize that the actuall gains will vary depending on the rest of my set up, boost level, etc. I'd much rather see M-Tuned save money in the development so they can pass the saving onto me then to spend it on dyno time and such to show you that it really does work. You should already know that it does work, there are no cons to a bigger tb.

Paul changed his TB and intake manifold on the "machine" and he saw a 30 hp gain. Idle was and is completely fine. He put on the BEGi intake manifold with the 70mm TB.

Well I'm worried about where the power is going to come in at. There is a slight chance that if it's too big it may hurt low-end or even throttle response, but it should most definetely help with top end and i would assume bottom end as well. I don't think slapping car on the dyno should be a big deal for a company like m-tuned.

Sorry Brain...the screws being secure comment had to be made, suprised noone said it sooner.

Great to see some interest. I was off from my real job last week and visited the CNC guy with John on Thursday. The CNC guy is quite interested in making them and they are probably going to start with a non Miata market item first. After those will probably be the Miata T-Bodies.

I know what you mean, but there are just too many variable.
I doubt a bigger tb will hurt low end, it's not like it is 5 times bigger, it's about a 30% increase, it is really only opening up a bottleneck, that's all.

That's because people fear the banstick, I see you are a brave one, too brave considering you have already had to sit out once. :giggle:

Chad told me that Paul doesnt use IAC anymore. Find out from him if he still has his IAC in place.

What size if the Manifold inlet on the NB? It won't do much good past that diameter.

Ill find out from him later. He's at work now and his phone is busted. He can't view anything on the screen. Either way though, his car idles fine. Would the IAC unhooked throw a CEL in OBDII cars?

Port it out :)

So what type of time frame do you think we are realistically looking at for them to be available?

Winter is my best guess right now...

why don't you make a coolant flange for the back of the head that has a port for the sensor and the heater core? That's something we can't seem to get put together.

Actually, please make one. I'll pay yesterday if its a reasonable price.

My $.02.

Speaking of gains in general without testing should probably be shown by an amount of horsepower expressed in a percentage of current horsepower. Throwing a large throttlebody on a 6psi 150whp car and getting 30more whp is a lot different than making an extra 30whp on top of 300whp @18psi.

There would need to be some testing with a couple of different common setups. I'd like to see it on a bandaid setup and on a standalone.
8psi T25
10psi GT25
14psi big GT25
15-18psi GT28
18-20psi+ GT30

If you could make 5% on the lower boost setups and 10% on the higher boost setups, it would be a cost effective upgrade at $250... providing there was also the same rate improvement in spool/response... or at least something measurable.

Going from a 2.5" to a 3" exhaust is worth about 10% and you're going to pay about $400 for that... so I'd definitely be "in".

It would also need to be completely PnP on the stock intake manifold, stock IAC, stock throttle cable, etc...

I have one question. How large is the actual inlet on the intake manifold. If the new TB is larger than the opening, then some porting/smoothing of the IM opening would be ideal as well.

Again, my $.02.

Off topic, but we have a coolant reroute kit coming and will probably sell some of our pieces separate. We are building a new housing for the rear from Billet Aluminum. All our Billet projects are usually built in quantities of 150+ so we will have lots of them. Making small 10+ runs is not cost effective = EXPENSIVE!

thinking out loud
 

The stock ford v8 tbs are used a lot on other cars as an upgrade route (boosted mx6/FE guys are using them). Wondering if an adapter kit is not a less expensive alternative... :dunno: The plate should be simple, the real hurdle would be PnP idle control. Would that (plate and harness) cost more that a used tb and a "kit"? And it would leave the buyer open to choosing the size TB they wanted. The 65mm 5.0 TBs usually sell for around $30 used with variable TPS and air control valve.

Right. Mustang TB's are dirt cheap.

I have no problem buying a good part, but when the chinese mustang TB's are sssooo cheap in comparison it'll get a little hard to sell.

Mustang TB are not that cheap. By that I mean the $30 price indicated above is not common. You may find an occasional used 65 mm mustang TB because not many people want them. Most upgrade to a 70 or bigger. New Ford 65 mm TB stil run around $150ish