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-   -   My spool sucks, help me! (https://www.miataturbo.net/diy-turbo-discussion-14/my-spool-sucks-help-me-42230/)

Rafa 01-02-2010 06:12 PM


Originally Posted by Nito619 (Post 503090)
Hola, saludos a España si te encuentras ayi. Mira el vtcs es algo como el puero secundario del mazda rx7 n/a y solamente funciona para una aplicacion sin turbo. En el rx7 esta operado de 2 maneras dependiendo de el modelo. La idea es de abrirse a las 4,500-5,000 revoluciones en el RX-7 y me imagino que en los miatas Mazda tuvo una idea similar, nadamas no se exactamente en que tiempo o que contrala cuando se sierra o se abre. Lo que se es que esta operado por una valvula de vaccum. Puede ser que se este serrando especialmente si cambian los niveles de vaccum con el systema de turbo.

Lo que te puedo decir es que desconectes la valvula esa para que este abierto todo el tiempo. Eso es de acuerdo a este articulo que por lo pronto te pueda interesar.
www.mazdaspeedy.com: Removing restrictive VTCS from intake manifold

That was a great post Nito! :bigtu:

Pretty good Spanish!

y8s 01-02-2010 06:30 PM


Originally Posted by Nito619 (Post 503090)
Hola, saludos a España si te encuentras ayi. Mira el vtcs es algo como el puero secundario del mazda rx7 n/a y solamente funciona para una aplicacion sin turbo. En el rx7 esta operado de 2 maneras dependiendo de el modelo. La idea es de abrirse a las 4,500-5,000 revoluciones en el RX-7 y me imagino que en los miatas Mazda tuvo una idea similar, nadamas no se exactamente en que tiempo o que contrala cuando se sierra o se abre. Lo que se es que esta operado por una valvula de vaccum. Puede ser que se este serrando especialmente si cambian los niveles de vaccum con el systema de turbo.

Lo que te puedo decir es que desconectes la valvula esa para que este abierto todo el tiempo. Eso es de acuerdo a este articulo que por lo pronto te pueda interesar.
www.mazdaspeedy.com: Removing restrictive VTCS from intake manifold

this is an english speaking site. sure, a dozen people here understood this, but the other 10,000 are going to not understand it and crack wise about it.

someone want to translate?

Rafa 01-02-2010 11:25 PM


Originally Posted by y8s (Post 503106)
this is an english speaking site. sure, a dozen people here understood this, but the other 10,000 are going to not understand it and crack wise about it.

someone want to translate?

Basically; the same thing you said in your post :giggle:

y8s 01-03-2010 12:43 AM

I guess I could have google translated.

Hello, greetings from Spain if you're ayi. Watch the VTCS is something like the secondary puero mazda rx7 n / a and only works for a non-turbo application. In the rx7 is operated in 2 ways depending on the model. The idea is to open up to 4,500-5,000 rpm in the RX-7 and I guess in Mazda Miatas had a similar idea, nadamas not exactly in that time or who saw or contralateral when it opens. What is that operated by a vacuum valve. It may be that this sawing especially if vacuum levels change with the systema turbo.

What I can say is that to disconnect the valve that is open all the time. That is according to this article that for now you might be interested.
It makes me wonder though. The early generation turbo 4wd toyota celicas had a similar system but it didn't have the same problems. I think they used dual runners and only half were blocked?

... more googling...

sure enough!
http://www.spagweb.com/gallery/ed_06...6_tvis_out.jpg

Nito619 01-03-2010 02:21 AM

That Toyota all-trac intake valve system is just like the naturally aspirated S4 and S5 RX7 where Mazda fitted this idea of having a dual runner style intake with half the runners being controlled via a vaccum operateed valve to ensure the best air efficiency at given rpm. This is why the guys at TeamFC3s.org say, ''the fun only starts at 5,000 rpm.''



This is a brief explanation of the purpose of those valves

TVIS = Toyota Variable Induction System. This system debuted in earlier Toyota MR2 and corolla. Instead of the normal 4 intake runners of an intake manifold, this manifold contains 8 runners. In between the manifold and the head itself, there is a plate in which 4 of the 8 runners have a flapper door than can be opened and closed as needed. Under normal cruising conditions 4 of these 8 runners are sealed, forcing all the air through the 4 small air ports. When the RPM reaches 4300 RPM, or the throttle is fully pressed (WOT), the flappers will open allowing all 8 ports to be open. This will create the effect of 4 large intake ports and thus open the door to higher performance upper end while maintaining low end responsiveness.
Celica All Trac and Gt-Four FAQ


I believe that Mitsubishi also had this kind of intake valve system in their Japanese counterpart of the 4G63turbo powered vehicles known at the cyclone intake. Long runners are used for low boost low rpm, when boost hits the short runners are opened up and massive amounts of air is directly forced into the cylinder head.

Cyclone Intake Manifold Setup - DSM Forums

Sentic 01-03-2010 05:07 AM

Haha, instant litterate :)

You said you inspected it visually, so this is probably unnecessary advise.
T3's tend to crack around the wg-canal if you run high exhaust temperatures, effectively enlarging to hole. Happened to 2 of mine...

y8s 01-03-2010 11:41 AM

the VTCS in the mazda is, unfortunately, not a power band adjustment device. It's only to increase port air velocity during cold startup to improve tumble in the cylinders and promote better air/fuel charge mixing.

ismael_pt 01-03-2010 06:46 PM

Thanks for the answers guys! I'll keep you updated.

ismael_pt 01-06-2010 02:57 PM

I plugged a OBD scanner and the stock ecu is reading 21º constant...


I can't reach the VTCS actuator with my hand :(

ismael_pt 02-02-2010 02:15 PM

Measurements of the turbo:

Turbine wheel:
Exducer: 2.48" - 63mm
Mayor : 2.89" - 73.4mm

Compressor wheel :
Exducer: 2.07" - 52.578mm
Mayor : 2.36" - 59.94mm

Opinions on the size? Maybe it's just too big.

Braineack 02-02-2010 02:21 PM

you sure about the compressor wheel inducer size? that suggests .76 trim

52.5^2 / 60^2 = .765


My spec are:

Garret T3 50 trim :
compressor: 48mm in. and 60mm ex
turbine: 48.7mm exducer and 59mm inducer.

eBay T3 50 trim:
compressor: 42mm in. and 60mm ex
turbine: 45mm exducer and 63.5mm inducer.



Your turbine must be stage III. Go find yourself a cheap 60 trim true T3 ebay turbo in a .48 housing.

ismael_pt 02-02-2010 02:30 PM

Not sure. I've got information from an eBay auction.

MonstA T3/T4 INTERNAL GATE T04E T04 600HP TURBO NISSAN - eBay (item 350311093158 end time Feb-08-10 01:30:30 PST)

It may not be a very reliable source but the turbo from the auction looks exactly as mine. I hard to source more info on this chinacharger.

Braineack 02-02-2010 02:38 PM

it makes more sense if the turbine and compressor specs get swapped :) then you're looking at compressor wheel bigger than a 3071's. and just fwiw, a t3/t4 :ne: a 60 trim T3.

A t3/t4 is a t3 turbo with a t4 compressor bolted on it. a t4 compressor wheel is typically huge and made to support over 40 lb/min (380hp)

ismael_pt 02-02-2010 04:21 PM


Originally Posted by Braineack (Post 516956)
it makes more sense if the turbine and compressor specs get swapped :) then you're looking at compressor wheel bigger than a 3071's. and just fwiw, a t3/t4 :ne: a 60 trim T3.

A t3/t4 is a t3 turbo with a t4 compressor bolted on it. a t4 compressor wheel is typically huge and made to support over 40 lb/min (380hp)

I was a complete noob when I started my build and I got this turbo because it seemed small inside the little housing. I had no specs of it when I purchased.

It also makes more sense if the thread title said "my big compressor spool pretty quick" :giggle: since the car is with the stock cat and muffler.

I have to take a look at ebay, wich size would you recomend Brain?

Thanks!

PD: Goal is 230-250whp with usable powerband

Braineack 02-02-2010 04:30 PM

price range?

kww502 02-02-2010 04:39 PM

Man that turbo and exhaust combo is killing your spool you should definitely change both.

ismael_pt 02-02-2010 04:50 PM


Originally Posted by Braineack (Post 517014)
price range?


As cheap as possible :laugh: 150-300$

Shipping costs are going to destruct my budget

timk 02-02-2010 05:24 PM


Originally Posted by ismael_pt (Post 517028)
Shipping costs are going to destruct my budget

I feel your pain!

swimming108 02-02-2010 10:04 PM

look at your adaptronic. I was spooling just fine (8-10 psi @ 3500rpm) before with my smaller turbo, but i too was getting a huge rush of power at 4200rpm which was accompanied by a 2psi spike and spinning tires. This was indeed the fault of the VICS system. I changed the AUX OUT 2 to an OR situation so that the VICS would open at 3500rpm or >60% TPS. This made a huge improvement in low end power and spool response. (i have no solid numbers on this improvement since i just made the change yesterday.) btw, i am also using the stock exhaust right now.

swimming108 02-02-2010 10:08 PM

try it, its free


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