von

Take off the TB and open the plates all the way up. I noticed that on the secondary butterflys...( the pair of 2) that they do not open all the way. Thiers like 5-10 percent blockage by the butterflyes. I noticed that one of my TB did it more than the other....Not Only that BUT the secondaries also are delayed. The primaries open first. Im sure this was a drivability reason but as far as response for the all out racer I found out a way to open them all at the same time and 100 percent open position instead of 90-95 or whatever.

On the end of the secondaries thier is the nut that fits on butterfly Rod...Under the bolt is this two pronged washer thing. Between those two prongs sits the rod that opens the secondaries. You will notice that thiers a GAP so when the cable opens the Throttle thier will be a delay in the opening between the secondaries and primaries.

I simply turned in a screw between those two pieces to join them and make them rotate as one unit. I have not driven the car yet but flame away please and let me know if thier will be any ill effect. This mod also let the secondaries open all the way.

Project84

Drive it. Go around the block a few times, then hit a highway at 75-80mph and come back and tell us how it went.

Jimmy325i

It might bog a little bit when you hammer on it. You might also have just kiled your gas mileage too. But I'm very curious as this will affect my big single TB conversion mental gymnastics.

dr0x

You know instead of ******* with them getting them to open at the same time, you could just remove them and grind the tb a bit.

mazdaspeed7

And people are asking why their n/a is getting 15 mpg...... And why my car is still getting 22-25 on a ported motor.

White_FC

I believe that the bottom butterfly opens by itself 'till about 15% throttle or something then they all open together, I think this way only the 'center' ports, which only have a very short duration, open up first which has got to be very good for your fuel economy, before the other 'outside' ports all open up (which have much greater duration).

Jimmy325i

I think I just reconsidered my big single TB and single chamber plenum idea. Dremel time on the parts manifold and TB!

I get 300 miles to the tank pulling max throttle stop light to stop light on my street port. ( I have way too much fun with this car)

NZConvertible

You're right, but it's not just for economy, it's for all-round better running. Because the engine is only breathing through the engine's primary ports, the velocity through them is much greater. This gives much better atomisation and mixing of the fuel, which improves throttle resonse, torque and economy.
You can actually feel through the pedal the point at which secondary throttles start to open (it gets a bit stiffer because of the second spring), and it's amazing how much time you spend using only the primary throttle when cruising around, mainly when at constant speeds.

Von, I'm holding my TB in my hands, and while you're correct that the secondaries don't open quite as far as the primary, I can't see it providing that much restriction. In fact looking straight down the secondary bores the visable area of the plates at WOT is only a bit more than the width of the throttle shaft!
You might find your mod causes a drop in throttle response when first accelerating from a constant speed, and a general decline in drivability at small throttle openings. Personally I wouldn't sacrifice that drivability for what is probably only a couple of hp at the most. I'll trust Mazda's engineering on this one, but I'll be interested to hear what your results are.

drago86

I i just put a properly sized and trimmed zip tie around the lil forked thingy that has the play in it that causes the plates not to open all they way, still has stepped opening and they open all the way now. Dont use one thats to big, youll pin the secondaries open a lil, even though they arnt being pused on any, and the car wont stay idling,...trust me

HAILERS

JPG

von

Thnx hailers , yes I did know that was mazda factory stuff having them open at diff times. But im sure this is for drivability at something under 4k like I might get a little stumble. But after 4k or so my response could be a bit better. we will seee. If not then I would like to know how to open the butterflys more without opening them earlier. Because mine only open like 80 percent serious thier like misadjusted...And to someones ? out thier im not talking abuot the cold start or first butterflyys when you do the TB mod. Im talking about the three at the end. Two on top and one on bottom.

And if this can gain a couple HP for a loss in drivablility man im thier. That will put me at 160rwp...lol we will see. Ill let you know

Jimmy325i

Modify the actuator cam. I haven't looked at it yet, but i should considering I have on sitting in my living room right now.

HAILERS

Ok. There is the fork that strikes the single tab that opens the secondary set. Take the 12mm wrench size nut off, the bushing and fork outfit. Just move them outboard for room. You don't have to remove the fork. Now take a pair of channel locks and bend the tab upwards so it'll be struck sooner. Use that pin with a spring attached as a lever for the upper part of your channel locks and the lower part of your channel locks on the tab that is to be bent. Now bend.

Outside of adding material either to the part of the fork that strikes the tab, or building up material on the tab itself, I know of no other way to make the secondary set of plates to open farther.

In fact I just now did it to a spare throttle body.

von

Hailers. I was thinking of bending that tab so it would open earlier but that would be like the same things as sticking the screw in it so they open as one. I mean that delay is factory and should not be changed. Any change is bad im sure. And I dont want to brake that tab off but mabey I will try it if this turns out bad...

I never complained about my gas mielasge Mzdspd7 I only drive her three times a month.

HAILERS

Well I looked at this throttle body in my hand and noticed that when the throttle was wide open, the second set were not fully open, like you described earlier. So the only way I see to get it to open fully is to bend the tab. That results as you said in both sets opening at the same time. I don't see any way we can have one without the other happening. Musta been designed that way........as in they didn't mean for the secondarys to open fully???????? Oh well, off to the tool store.

ebay7

All I did was cut a small piece of 4mm vac hose and inserted into that copper looking tab giving it 100% WOT. I had this rigged for 3 months now and it's holding up pretty good. Drivability is good since it only comes into play at wot. I did not feel any difference at all from this mod. What the heck, it took less than 2 minutes to install and it didn't hurt idle or cruising at all.


Deep down in my mind, I swear that with enough air rushing thru, those 2 plates would pull down like that of airplane foils giving it 100% wot anyway, making this mod totally unnecessary, no?

von

no

HAILERS

This remark caught my eye by NZ **and it's amazing how much time you spend using only the primary throttle when cruising around, mainly when at constant speeds. ****

I finaly got off my duff and warmed up my 87 to full temp. The meter on the tps said one volt at idle. I got out and popped the hood and moved the throttle til it just reached the point where the linkage was going to move the secondaries open. WAlla! Just 4.5v on the meter. My tps's top range is 4.80... so from past experience of watching my tps while driving, I know that when driving on the hwy I'm almost always below 4.5v at seventy.
So NZ is right about how the long primarys are used a lot more than we might think(without the secondarys being open).

And the real reason for writing this.....did NZCONVERTIBLE finish his throttle body mod. And does he experience the dreaded hesitation when going full throttle as described in another post ?????

EDIT: This is the other post.... https://www.rx7club.com/forum/showth...hreadid=147524

NZConvertible

Yes! Yes!

Seriously, it's no big deal. Like I said in that thread, you get used to it pretty quickly. You learn how fast you can open the secondaries without it stumbling. I am pleased with the increase in throttle response from doing this and recommend it. Just don't be too concerned when you floor it on your first test drive and it stumbles badly; even I was a bit surprised. You'll quickly get used to how it all works and will notice the improvement.

HAILERS

I'm not trying to make this the most drawn out thread online, but........I still don't understand. I have a truboii that has the dashpot off along with the black cam that itl rode on off. Therefore the secondaries open at the same time as the primaries. I don't notice squat in the way of hesitation on throttle application. I don't see how removing those two plates could cause anything in the way of hesitation (vs the secondarys opening at the same time as the primaries).

von

Ok sorry for the late delay but I test drove my 89GXL with the plates all working together ( same time) and the response is better than before. My car dose not hesitate or bog at all but its jerky somtimes if I barely tap the gas it will launch the car hard if im in 1st gear around 2k rpms. It seriously makes me feel like I have more power but im sure its not thier.
The Top End is noticably better since my 2nd plates finally open now all the way. Thats about 10 percent more air coming through from the way my plates were before. The car revs to 8500 just as fast as 7.5-8 so I know for a fact I gained mabey 2rwp up top...

By the way when I did this I also had the TB ported and polished wich may be the reason for the slight HP gain but its very mildly ported just knife edged and polished.

BDC did this and I recomend him to anyone...Very mataculous job pluss he cleans everything and takes all the unecesary stuff off the TB...

People will say things like oh you will lose low end because of the decrease in velocity due to the extra air of the secondaries..But this is in theory and it is true in most cases but I noticed that with them opening together on my setup im sure I didnt lose anything if not gained a little.

silverrotor

iTrader: (1)

How drastic Is your fuel economy after doing this mod? I noticed poor fuel economy after doing this mod and am considering to re convert to stock standards despite the slightly better throttle response.

von

Didnt check so cant say. Obviously not enoughf to drop my jaw but I will give up a few MPG to gain a few RWP if you know what I mean hehe.

von

By the way not to confuse anybody im only into streight line. Some cornering ( still handles better than friends miata) but I have been getting the car ready for the drags this february at qualcolm stadium...All I care about is droping tenths...Drivabilit right now is awsome.

I think the reason why I didnt lose any from this mod and the theory of port velocity is because my VDI and 6th port are all open so the extra air acutally helped or did nothing at all...I mean why put a little bit of air throught the primaries on the TB just to let it into all 4 ports at the same time? It would be a benifit if it went into only the two hence the VDI and 6th ports funcioning but like I previously said this is on MY setup wich will differ with other poeples setup im sure...I will get more dyno results for proof withlin the end of next month.

silverrotor

iTrader: (1)

At the time of removing the Secondary Plates, I removed my Cat. Perhaps this had an additional effect on my fuel economy?