Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

XT6 throttle body on spider EA82T's


  • Please log in to reply
31 replies to this topic

#1 Dennis ex24

Dennis ex24

    Subaru Disaster

  • Members
  • 2,683 posts
  • Phila, Pa

Posted 10 March 2004 - 09:21 PM

has anyone proven this mod yet?

i see some guys mentioning it, but does it fit on our manifolds?

#2 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 10 March 2004 - 09:29 PM

Yeah, lets go ahead and let this secret I found out of the bag...ive go two spyders and two xt6 throt bodys....i guess its time to get to work.

I know the bolt pattern is way different when compared to the non-spyder intakes.

#3 scrapdaddytatum

scrapdaddytatum

    the subaru surgeon

  • Members
  • 790 posts
  • charlottesville, virginia

Posted 10 March 2004 - 10:23 PM

im looking to do the conversion, as soon as i find a throttle to use

#4 Myxalplyx

Myxalplyx

    Old Wise and Dumb

  • Members
  • 1,834 posts
  • New Castle

Posted 13 March 2004 - 04:05 PM

What's special about the XT6 throttle body? Is it any bigger than a stock 1.8ltr throttle body? I measured it at 2.75".

#5 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 13 March 2004 - 10:05 PM

the stock EA82 MPFI and turbo TB is TINY compared to an XT6 TB.

#6 XSNRG

XSNRG

    Elite Master of the Subaru

  • Members
  • 3,657 posts
  • Olympia

Posted 14 March 2004 - 12:50 AM

It is definately not a bolt on. The bolt pattern on the XT-6 is bigger.

I'm trying to figure out how a the bigger diameter throttle body will help performance? It seems like things would be just great until the air hit the square shoulder of the smaller size intake???

#7 GLCraig

GLCraig

    Livin' the live

  • Members
  • 2,706 posts
  • LV, Washington

Posted 14 March 2004 - 01:58 AM

too big of a throttle body is going to give you poor throttle responce.

#8 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 14 March 2004 - 07:07 AM

Well ofcourse you would not leave the old shoulder there!

And T response......well......there are ways around that........Anti-Lag!

#9 scrapdaddytatum

scrapdaddytatum

    the subaru surgeon

  • Members
  • 790 posts
  • charlottesville, virginia

Posted 14 March 2004 - 09:09 AM

i know the xt6 is bigger, i have a spare spider intake i plan on boring out to take it, i have machining capabilities

#10 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 19,914 posts
  • WV

Posted 23 September 2005 - 10:55 AM

okay, who's ready to disable the search function now??

i'm putting together an EA82 that i want for good gas mileage...yeah that's right, that's how lame i am. would installing an XT6 throttle body on my EA82 offer any highway, long distance gas mileage increases? i have a few extra XT6 motors so i figured why not ask?

i guess it wouldn't be that hard to test and if it didn't help gas mileage i can swap back to the EA82. maybe i'll be the test mule for this.

#11 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 19,914 posts
  • WV

Posted 23 September 2005 - 10:58 AM

well i just thought that i can't swap back to the EA82 TB because i would have to machine the spyder intake to work with the XT6 so it'd be too big of an opening for the original. dang it.

#12 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 23 September 2005 - 11:01 AM

TWE header, DP, intake.....thats 28 mpg around town and 35 hwy. :headbang:

#13 Subi81

Subi81

    1000+ Super USER!

  • Members
  • 1,006 posts
  • Ventura, Ca

Posted 23 September 2005 - 10:37 PM

That big of an improvement on MPG DAM!!!

#14 suberdave

suberdave

    www.suberdave.com

  • Members
  • 1,001 posts
  • Covington

Posted 24 September 2005 - 12:44 PM

i know its not an XT6 TB but it is bigger and using a plate like this you could put any TB on a spider

I finally got my GM 2.2l Ecotec throttle body on my spider intake. It’s about ¼ inch larger bore and it has an idle air controller for MS&EDIS




Here is the spacer plate that my little brother cut for me on a waterjet.



Posted Image

This is what it looks like all put together.


Posted Image

Posted Image


Now I just need to get my MS&EDIS so I can use the IAC. And I guess it has to be in the car before it will work….

#15 BoostedBalls

BoostedBalls

    Subaru Fanatic!

  • Members
  • 444 posts
  • Cornelius, OR

Posted 24 September 2005 - 01:36 PM

I don't think it would be a good idea to use an XT6 throttlebody on ea82t spider intake.

The plenum volume, intake runner diameter and length, plenum inlet (throttlebody) ratios will be thrown off. The inlet diameter actually has a lot to do with reverberation pulses that occur inside of the plenum chamber. This is designed with the Helmholm resonator theory in mind. This will change pulse signals inside the chamber and thus change performance. I think it would reduce the pulse amplitude and reduce power.

It might be cool to try it. But I think the small stock throttlebody is not a bottleneck to the system when it's flowing at 15psi in a turbo engine. I would be more concered with the MAF sensor's ability to flow with only atmospere helping it.

#16 TomRhere

TomRhere

    Certified BRAT nut!!!

  • Members
  • 3,995 posts
  • Hillsdale, Mi. USA

Posted 24 September 2005 - 02:59 PM

I don't see where it would be a "bad thing" to do. Would compare to putting the EA-82 carb intake and a Weber on the EA-81 engine. Makes 'em "breath in" better. Done that twice now, the '84 BRAT I had, and the '86 BRAT I'm driving now. Need to get a freer flowing exhaust on it though...

If one does a proper job of machining the intake, (or an adapter), and does a little port-n-polish on the intake runners and head ports, coupled with a free-flow exhaust, I think it would be a little screamer.

I've only seen one Spider intake in person and that was a while ago. But aren't the runners off-set from each other side to side? I believe they are, and made that way so that the "pulses" don't cancel each other out when they re-bound back into the plenum chamber. Going to a bigger TB shouldn't have any detrimental effect on that, anymore than ripping the factory stock intake and carb out on a Chevy 283 an slapping on an Eldebrock intake and a 600 carb. Lots did it, and loved every minute of it.....

Just my "old" .02...........

#17 grossgary

grossgary

    Elite Master of the Subaru

  • Members
  • 19,914 posts
  • WV

Posted 24 September 2005 - 03:28 PM

different length runners like you said. from what i've read on polishing you don't necessarily touch the intake side as the induced turbulence through the fuel injection manifold helps mix the fuel. i don't know much, i've only done it once myself.

#18 TomRhere

TomRhere

    Certified BRAT nut!!!

  • Members
  • 3,995 posts
  • Hillsdale, Mi. USA

Posted 24 September 2005 - 04:02 PM

different length runners like you said. from what i've read on polishing you don't necessarily touch the intake side as the induced turbulence through the fuel injection manifold helps mix the fuel. i don't know much, i've only done it once myself.


Yeah, you don't really want to "polish" the intake side, but smoothing it out some does wonders. You want to get rid of any casting flash or bumps in the runners or ports, and leave it with a "roughish" finish. Smooth really, but not "polished", you want to see the stoning marks. Now on the exhaust side of this, you want it as smooth as possible, "polished" as in near glass smooth, but not quite that smooth.

#19 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 24 September 2005 - 04:09 PM

with and N/A engine...it matters more for the intake runners and such...ona turbo engine....more air in, the better. PERIOD.

At some point, I will get a larger TB on the RX, but on the STOCK intake manifold. I dont think the spyder/'flatty' difference will net any gains when they are used in turbo applications...large TB or not. N/A on the otherhand....there will be a difference.

There IS a reason why the main chamber is larger on N/A subies vs turbop subies.

Also, look at the nex 05+ N/A intake manifold....its a nice work of art. Turbo ones remain the same from 2000.

#20 BoostedBalls

BoostedBalls

    Subaru Fanatic!

  • Members
  • 444 posts
  • Cornelius, OR

Posted 24 September 2005 - 06:09 PM

Well, a couple things...

The intake plenum on a V8 engine doesn't make use of the Helmholm resonator the way a 3, 4, or split intake V6 does. A 3 cylinder chamber is ideal and anything over 4 is loosing pulse intensity and timing.

The plenum volume is less critical when talking about turbo engines but there is a gain in power by using the right size. The same is true about header collectors in turbo and N/A engines.

IMO, the spider intake is superior mainly becaise of the wider radius that the intake air has, giving more velocity and smoother air flow into the chambers.

The spider intake will probably not work as well as the plain one in a carbed or TBI system because (A)the radius is too smooth to keep fuel suspended in the intake charge. That sharp 90 deg bend right before the inlet on a plain intake was designed with carbs in mind. (B) The large plenum will weaken pulses needed to make the carb do it's job right. © The large plenum will allow a decrease in velocity, allowing the fuel to drop out of the air. Fuel weighs a lot more than air.

The texture of the intake ports should be as smooth as possible in a MPFI system, the rough texture only helps to aggitate an air/fuel mixture to keep from puddling in a WET manifold (SPFI and carb setups). We are talking about DRY manifolds here. That air should glide through the intake with as little turbulance as possible, the turbulence is only a good thing as the WET mixture is blowing into the cylinder to help flame travel. This is the concept that most newer performance engines utilize.

#21 BoostedBalls

BoostedBalls

    Subaru Fanatic!

  • Members
  • 444 posts
  • Cornelius, OR

Posted 24 September 2005 - 06:28 PM

Here's an article that does a good job of sumarizing it without too much engineering lingo.
http://www.grapeaper...tionsystems.pdf

And I mispelled it, it's a Helmholtz, not a Helmholm resonator.

#22 discopotato03

discopotato03

    USMB is life!

  • Members
  • 227 posts
  • Sydney Australia

Posted 26 April 2008 - 09:33 AM

I look at these things a bit differently but firstly my plan with the Spider on an EA82T in an RX L series .

I have three spiders which is minor miracle in Australia where very few were sold .
The XT4 TB and TPS is a PITA in an L series mainly because its designed to work with the Vortex engine bay and throttle cable set up .
My plan is to cut or mill the back face of the plenum so that garden variety L series TB's can be fitted with an adapter plate . I think it will have to be spaced out from the plenum casting because the throttle quadrant wants to foul on it . Once this is done either the L 3 plug or 4 plug type TB/TPS can be fitted and used .

There is a direct relationship between throttle size , plenum volume and power characteristics .
Firstly the plenum chamber needs to have enough reserve capacity to not suffer major pressure drops as the cylinders and manifold runners demand air from it . Each cylinder is an on and off situation where the throtlebody becomes a constant flow device . In a perfect world there wouldn't be a single throttle plenum manifold , it would have individual throttles bolted on above the injector mount stub pipes and so achieve almost no flow loss throttling . This would make for razor sharp throttle response and a higher dynamic or effective compression ratio . Restrictive inlet systems limit how completely the cylinders are filled/charged , less filling means less to compress so less power into the crankshaft .

I personally think the spider manifold could use a slightly larger TB though it would help if its runners were ported out a bit too . One of the stumbling blocks would be getting the std computer to cope with the sudden extra airflow potential if a larger throttle was opened suddenly .

Some examples of multi throttle production turbo engines are the Nissan Skyline GTR RB26DETT and the Pulsar GTiR SR20DET . I've seen picks of EJ turbo engines with 4 throttles as well .

Gas speeds into the ports is less important with flap/hotwire AFM EFI systems because its the AFM measuring the airflow and fueling accordingly . With "wet" manifold systems like a single carb or SPFI rough castings and sharp angles do help keep the fuel in suspension in the inlet air .
With EA82 MPFI , and specifically the Spider inlet manifold , the injectors are pretty close to the heads a spray a fine mist virtually strait down the ports necks . Most of the "bridge" section of its plenum is above the injector boss stub pipes so its mostly only ducting air .

Enough for now , cheers A .

#23 WJM

WJM

    SUBARU

  • Members
  • 7,828 posts

Posted 26 April 2008 - 08:07 PM

All that matters is when I get around to it...ITBs and two VF7s.

#24 discopotato03

discopotato03

    USMB is life!

  • Members
  • 227 posts
  • Sydney Australia

Posted 27 April 2008 - 01:48 AM

If your thinking of hanging a turbo off each head just remember this .

You need to have two cylinders exhausting into each turbine housing but they need to be the front and back two pairs not the ones on each bank .

The factory solution is one twin scroll turbocharger and the TS manifold from the factory is quite good .
The TS system is a lot less complex and lighter overall than twins .
The hardest part is getting a turbo with a twin scroll twin integral gate turbine housing so you can avoid the agro and expense of one or two external wastegates . A couple used on Subaru EJ20's are VF36 and VF38 and if there was ways of grafting reverse rotation TS Evo Lancer turbos on then these can support healthy numbers .

Your call .

#25 joostvdw

joostvdw

    Subaru Nut

  • Members
  • 609 posts
  • Holland

Posted 27 April 2008 - 12:32 PM

I don't know if this is any usefull information here, but I will post it anyway.

I'm having troubles with the AAV on my EA82T and replaced the electronic shutter valve with a simple manually operated valve, just to see how the engine runs with it open, closed or halfway.

With it fully opened the idle shot up to almost 2k rpm, but I also gained quite a bit of power higher up in the power band. And since this is all taking place behind the MAF the mixture is staying the same, I'm just making more of it.

So if I'm not mistaking, this auxillary air passage is acting like an extra throttle body (albeit a constantly open one) and this increase in air flow is definately helping power.

This is already on a 140-150hp EA82T (EDM spec, decatted and 2,5'' TBE) so perhaps it's only of use on higher hp numbers, I don't know, just throwing it in the mix.




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users