does 64mm throttle body needs intake manifold inlet to be bored to same size?
 

Like the title says, does 64mm throttle body needs intake manifold inlet to be bored up to the same size as the throttle body to gain performance? Or do they mate up to the same diameter without modifications?

Believe me, I tried to search but could not find any posts regarding this.

You may find these helpful:

https://www.miataturbo.net/attachmen...ine=1366153558
JD/UK/EUDM "Squaretop" manifold upper plenum throttle body inlet

https://www.miataturbo.net/attachmen...ine=1366153558
Squaretop with Skunk2 gasket (notice the "ear" at the top of the photo with no gasket coverage)

https://www.miataturbo.net/attachmen...ine=1366153558
Potential vacuum leak on backside of throttle body, right next to "ear." Pencil line represents the overlap between the manifold and the throttle body... not much meat there.

https://www.miataturbo.net/attachmen...ine=1366153558
OM NOM NOM NOM!!!

https://www.miataturbo.net/attachmen...ine=1366153558
Throttle body to manifold. This would be the material you need to remove for a smooth transition. This is a tracing of the throttle body, NOT the gasket. I did this with the gasket removed.

https://www.miataturbo.net/attachmen...ine=1366153558
For fun: Skunk2 gasket against stock NB throttle body.

This is all still sitting in my garage, LMK if you need more pics.

Edit: Put some tags on this thread so others can find it :party:

/\ Very cool thanks gordon

Very welcome, I try to give back where I can.

It would be nice to hear from some other guys running the 64, I'd like to see how far they went with port work, if any.

Wow, thank you so much for the detailed reply, what happens when you line up the gasket with the intake manifold that has the lines drawn from the bigger throttle body? I assume that the gasket outlines are bigger than the drawn line?

There is play / slop in the mounting holes, when you install it open the blade and look and feel to get everything centered before torquing the bolts. Of course this is after you port the manifold as in the above post. Also to note, mine is a 94 car with a square top, and I tried to use the '94 TPS, but with the adaptor, it would hit the valve cover. I ended up changing to a 99 TPS and pigtail. IAC valve worked fine.

I'll dig out the parts and take a look tonight. I think I completed the radius section that I couldn't draw with my pencil using the gasket (it was blocked by the throttle butterfly and shaft.) But I'll see if I can't get a pic. If memory serves, the gasket is damn near perfectly matched to the throttle body itself.

I seem to remember either Emilio or Savington saying that they just pop these on and run them, but I'm too lazy to go find the comment. Its probably buried in the broken throttle shaft threads.

They work and may gain a few whp up top without matching. More gain when matched. If your rules (no rules?) allow it, match the darn thing.

I couldn't have said it better myself :party:

Holy thread revival Batman! I'm running a basic intercooled setup (NA 1800 Eunos import) with a td04l13t at 15psi with a mspnp2. I'll be ripping a quick power run today then installing the ported inlet and skunk2 followed by another power run in the next few days to see what's what. The dyno is the best in the area and has a built in weather station all sorts of fancy features so is the best I can do without fitting the thing at the garage on the same day.

I do have thermal spacers for the head to inlet and TB to inlet but I really cant see this affecting results much under dyno conditions.

I have no clue what's going to happen but i'll post up back to back dyno sheets on here if any of you guys are interested.

https://www.miataturbo.net/attachmen...ine=1467795825

https://www.miataturbo.net/attachmen...ine=1467795825

https://www.miataturbo.net/attachmen...ine=1467795825

https://www.miataturbo.net/attachmen...ine=1467795825

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You better blue locktite every threaded thing on that throttle body.

Ive done the stop screw already but everything?

Some QC issues been going on or what?

Over the years we have had many reports of the screws/nuts working loose. Not the ones on the throttle shaft or the butterflies mind you, but definitely the rest of the smaller ones. Just get everything set up the way you want it and then R&R with some appropriate (read: non permanent) threadlocker.

The color is not my bag but I do like the powdercoat, looks like it came out really nice. I'm guessing with the 2 post count you don't have an intro or build thread? You should go make both :bigtu:

Essentially, yes. We view the Skunk2 as a "throttle body kit". A starting point.

Between myself and a few other vendors, Skunk2 has been thoroughly informed of each concern in detail going back about 4 years. They just don't care. Thus why we are working on our own TB for 2017.

Cheers for the heads up guys! :D
I'm a UK Eunos owner and have dipped into here for bits of info but not got balls deep yet because all the info is available without looking stupid by asking dumb questions and annoying people (I know you guys can be savage ;) )
I'll throw a bit of a build thread together this week :)

Car dynoed at lunchtime gave the following so lets see if she makes gains with the new system.

https://www.miataturbo.net/attachmen...ine=1467820628
https://www.miataturbo.net/attachmen...ine=1467820628

https://www.miataturbo.net/attachmen...ine=1467820628

https://www.miataturbo.net/attachmen...ine=1467820628

looks like a nice little car!

Thanks man. She was a POS when I picked her up but quite a looker now and has the performance to back it up with the turbo :)

aside from the tsi and vented flip up panel, nice!

Thanks man, the tsis and vented lid are two of my favourite parts :sad2:

:D

different strokes!

Seeing this dissatisfaction and looking for other throttle body bolt patterns last night I noticed that the sr20det and rb20 throttle bodies have the same 60mm square bolt pattern as the 1.8. Did anyone ever test to see if the throttle shafts on these break?

I'm ready to fit the TB guys but I gotta be honest I'm a little confused by the 2 parts pictured at the front. The elliptical part I guess forms the tps housing and the rotor bit has slipped over the 'blade' for the tps but what is the odd shaped gasket for? Confused :/

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Is there a gasket on top and on the bottom of that idle valve adapter plate thing? Mine was for an NB so the idle valve adapter is set up a bit differently so I'm probably no help, sorry. I know the NB one goes together like a puzzle designed by the Mad Hatter with no instructions.

You're right: I'm dumb

Haha

Thanks buddy. I'll put it down to a long day :D

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The inlet swap has really been awful but I'm no mechanic. Now I can see light at the end of the tunnel what gains do you think I'll see if any?

I'm sure someone has done before and after but I can't find it at the moment. For us, TB is more about reliability than any serious gains. A $325 throttle body is cheap insurance to protect a $2000+ built motor. These engines tend to make more power when they are not trying to compress fragments of the throttle shaft or the butterfly screws ;)

Yerp I can agree with that. If I see a couple of hp at the top I'll be happy. It's green and shiny. What more can you ask for ?? :D

Ok, now go make a intro thread: Meet and Greet - Miata Turbo Forum -Boost cars, acquire cats.

Tell us about your car, your self, your mechanical abilities, your cat, your goals, etc. We tend to respond well to visual stimulus so post lots of pics.

...and follow it up with a build thread: Build Threads - Miata Turbo Forum -Boost cars, acquire cats.

Again with the pics, everyone loves pics. :bigtu:

Yes mate sorry. I'll probably need an hour in front of a desktop so probably tomorrow at work. I'll try to keep it concise (ish) with lots of pics :D

Andy

you are making me paranoid

I just came across this recent oopsie on my UK forum on a 300whp 1.6

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Ugh, you guys. I don't want to pull my manifold yet lol.

FWIW he has blobbed some epoxy over the screw heads so if they do fail there is less chance of them being munched.

Seems like a sensible compromise!

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better off pulling the throttle body and hitting the back side of the threads with a chisel

The epoxy is kind of a band-aid. When I worked with a certain race team that fielded 4 Miatas in a certain endurance race, 3 of the engines had Skunk2 TBs and one had an epoxied stocker. I'll let you guess which car went out on a mechanical and what the root cause of that mechanical might have been.

Hell, if you want more evidence, you need look no further than here: https://www.miataturbo.net/prefabbed...e-wheel-81058/ and the title of his new build thread is... https://www.miataturbo.net/build-thr...rebuild-81161/

Lets pull it off, and I will port match yours as I did mine, I can also get you a TB from the same place I got mine so we can protect that motor!

I'm also a not so proud member of the throttle body ingestion club. Its typically not the screw backing out that is initial problem, its the throttle shaft cracking at the screw hole. Then the screw comes free. Mine was expoy'd to the shaft and still made it into the intake manifold and #3 cylinder. I was lucky that it was a through-and-through and no major damage was done. If you don't want to pull your intake manifold, just install the Skunk2 TB without porting.

Don't you have a squaretop on that BP6D? All you have to do is pull the top half of the manifold. Quit yer bitchin' it'll take you like 15min ;)

Besides, you don't actually have to port it at all. Some of us just have that level of OCD.

But gasket?

So order a gasket. http://miataroadster.com/mazda/mazda.../i-464139.aspx

Oh snap, I have no more excuses. Looks like I'll have to do my fuel upgrades sooner than later too.

Right it's all fitted and running sweet with no leaks. Sure feels like less pedal makes more throttle due to the bigger butterfly which is fun. Not sure if it will gain any peak power but time will tell! Looks cool none the less Attachment 176527

Slight whistle at part throttle due to resonance down the channel to the idle control valve (from reading a post on here) but barely audible over the exhaust and choo choo

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This sounds like content that should be in a build thread ;)

Done it. 144 views and one comment. Meh :(

It's looooong and not bandwidth friendly :D
Andy
;)

Well the results are in and it's not what I expected at all. The car felt quicker and we will see why in a minute. I'm pretty sure it's all gone back together as it should with no boost leaks so let's go on the assumption that this is the case.

Today was hotter and a lot stickier than last run but I had a chance to get down so had to take the opportunity.

Peak torque and power figures were down from last time I'm sad to say (-5hp and -7Nm). I was mortified by this I'll be honest. The guys at the garage said that the hot and muggy conditions will have accounted for this and a freeer flowing mani won't be detrimental to peak power so read it as "makes no difference"

Not sure if they were trying to make me feel better but I'd have liked to have seen more or the same peak power. Never mind it's an experiment.

Anyway now for the exciting part. The engine makes loads more power as it comes onto boost now between 3 and 4k in fact it makes a huge lump in this area which is why it feels quicker.

I've tried to get a rough idea of figures but at 3.5k rpm it's making circa +17hp and +30Nm (22ft lb)

This is a result in my eyes big gains from quicker spooling makes for big fun. I'd like to see the peak power back but maybe on a crisper cooler day.

Sorry for the ramble it's been a long week.

Dyno sheet here

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Whatever, more power early on is a good trade off for marginal difference up top. I'd be happy with gains like that and the security of not having screws fly into a built motor.

I agree especially for a road car. It really gulps in that boost and gets on its toes now. Overall I'm happy :)

Ok,I have the tb,now need a built motor to put behind it. Oh and some ac in the garage. Yes,wooos!

Nice one. Are you porting out your inlet mmanifold?

Yes , but first must buy eurosquaretop, since this is a change I want to make