Issues associated with turbos AND ITB's?

[sorrowfulkiller]

I'm in the air guard, going to be coming back from basic and tech in feb-mar 2010. I'm planning on buying a s13 with a ka24de, dropping like 12k into it to make it a fast and fun street car.

Here's what i want to do in a nutshellgt2871r turboaem ems + uegohomemade ITB setup with surge tank

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I've thought up a couple problems and questions associated with such a setup

1. Idle Control

My first thought on idel control would be to tap each runner with some vacuum fittings, run these vacuum lines to a vacuum block. The vacuum would be coming from an area that is pre turbo and would have some sort of solenoid connected to it (stock wrx 2 port Boost Control Solenoid is what I'm thinking) This way it would be a simple setup to use, simple on and off switch and should be able to control it with the ems (hopefully)

2. Brake booster

I figure either i can use a vacuum source pre turbo without a check valve or just a runner-vacuum block source with a check valve. Not sure what i should do in this aspect...

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I have software on my computer called engine analyzer pro that will allow me to put in the ka24de engine info (bore, stroke, runner length, compression, ect...) so I can figure out the most optimum runner length for such an ITB setup. I'm planning on cutting off the stock manifold flange (or buying one if I can find one) Welding on specific length runners, putting a flange on the runners to mate to some type of motorcycle ITB's. Bolt up the motorcycle ITB's and attach velocity stacks to them, then weld the Velocity stacks to a flat piece of metal for the base of the surge tank. Weld the outside of the surge tank from a 3/4 piece of pipe, weld up the ends and cut a hole in one side for the inlet and weld on piece of pipe for the silicone coupler to attach to.

Any questions or suggestions to my plans?

[480sx]

ITBs are for the most part, an idiotic waste of time of a turbod car. The biggest pain in the a**. 8 throttle body seals for boost leaks? 4 ITBs that have to be perfectly insync and stay that way for you to see any gains and not limit airflow to one cylinder. There are so many problems with associated with ITB's and turbos, especially once you start running more boost.

The gains a turbo motor sees from ITBs are close to nothing.

Keep the stock IM for a street car.

Also if your dropping that kind of coin, you should be running a t3 turbo. The t2 flange is hard on a Ka once you crank up the boost, your drive pressures get messed up and you start blowing gaskets and the turbine starts to try and fly out of the turbo at about 1:1.5(boost/drive pressure[pre turbine exhaust manifold pressure]).

A t3 50 trim t3/t4 stage 3 turbine .48 ar exhaust housing makes for an insanely responsive Ka-T for 350 hp and under. Its what i would recommend, that or a borg warner S series.
Modified by 480sx at 1:19 PM 5/26/2009

[sorrowfulkiller]

This is the main issue. I didnt read your post.

It is an idiotic waste of time, and the biggest pain in the a**. 8 throttle body seals for boost leaks? 4 ITBs that have to be perfectly insync and stay that way for you to see any gains and not limit airflow to one cylinder. There are so many problems with associated with ITB's and turbos, especially once you start running more boost.

The gains a turbo motor sees from ITBs are close to nothing.

Keep the stock IM for a street car.

Reason for ITB's? very very quick response

for instance both jun and team orange both use ITB's on their impreza's and EVO's

There's a reason for this, and it does make gains over a single throttle body setup... but you'd likely have to ride in the car to see responsive gains and see a dyno chart for hp or tq gains

[sorrowfulkiller]

It's not going to be a daily driver. More like a fun weekend car.

I'll probably have the surge tank designed and made by a local expert at intake and exhuast manifolds so that the surge tank is made so one cylinder will not be getting more airflow than another. I trust him with his manifolds and how they are made.

The turbo comment however, I haven't decided what turbo I will absolutely go with, I still have a lot of time to figure this out since it's about a year away from the time I actually get the car. The reason why I want to go with the GT2871R is because I've looked at the compressor maps for what i want in terms of power (350-400 chp) and it seems like it would be a great choice (always in efficiency range from 3k til 7k) and it should spool very quickly.

Currently I'm looking into the Borg Warner turbos you have suggested. I don't like how the compressor maps for garret turbos larger than the gt2871R look for a 2.4l engine with my power goals in mind, either too high a boost threshold or they are way too efficient at over 7k, as I am looking for a peak power goal around 5500. I have no experience with turbonetics turbos, how do they compare in reliability, spool, power and efficiency to a garrett or a borg warner?

The one word that describes what I want is: Powerband

EDIT: Looks like the S2B Borg Warner turbo would be a viable turbo for me... I'll look into it a bit more

Also looking into a stg 3 .63 trim like you said

Modified by sorrowfulkiller at 2:15 PM 5/26/2009
Modified by sorrowfulkiller at 2:49 PM 5/26/2009

[480sx]

The response increase you get IMO isnt worth the hassle of the system itself. In addition, the primary 'increase in response' is seen out of boost for an ITB system. You have to remember, the primary determining factor of response in a turbocharged car is the efficiency of the turbocharger. I suppose for a race car i might consider it.. More just to see if it was worth doing or not. You wouldnt see much HP/TQ gains with that, if anything at wot its a restriction and a disruption of the air path.

While you name two companies who use ITB's on a turbocharged motor, i can name 100's that dont lol.

As far as turbos go, check out a s256. Perfect turbo for your goals with a good amount of headroom.

The GT2871R chokes a ka on the exhaust side over 350 hp pretty badly. All the t2 flanges do. You can compensate, but you need a hell of a wastegate system. Just not worth it.

For your goals, and considering response and powerband is an issue, stick with the stock IM! Tellin ya dude, there are no other better options.

[sorrowfulkiller]

The response increase you get IMO isnt worth the hassle of the system itself. In addition, the primary 'increase in response' is seen out of boost for an ITB system. You have to remember, the primary determining factor of response in a turbocharged car is the efficiency of the turbocharger. I suppose for a race car i might consider it.. More just to see if it was worth doing or not. You wouldnt see much HP/TQ gains with that, if anything at wot its a restriction and a disruption of the air path.

While you name two companies who use ITB's on a turbocharged motor, i can name 100's that dont lol.

As far as turbos go, check out a s256. Perfect turbo for your goals with a good amount of headroom.

The GT2871R chokes a ka on the exhaust side over 350 hp pretty badly. All the t2 flanges do. You can compensate, but you need a hell of a wastegate system. Just not worth it.

For your goals, and considering response and powerband is an issue, stick with the stock IM! Tellin ya dude, there are no other better options.

I understand completely what you're getting at now.

Okay, no ITB's then. I'm guessing porting and polishing the intake manifold can cause some sort of gains correct?

On the turbo aspect I see your point with the gt2871r, and I'm looking at the turbonetics turbos a bit more. Are they all oil cooled? Know anywhere where I can get a compressor map for the t3 turbo you mentioned?

[480sx]

There are quite a few s256's, just as there are quite a few gt3071r's. I think its kinda stupid how they call a turbo simply by its compressor and say nothing of its turbine wheel.. Anyway, there is really only one turbine wheel you want for this engine, and i cant remember what size it is off the top of my head. If you need more info about the BW turbos, email me at [email protected].

[sorrowfulkiller]

I've been looking in the sr20 forum a little and it seems people are having great success with the gt2871's on the sr20's, and the power is slightly more to the right with them than it would be with the 2.4.

I'm still thinking the T25 flange xD I want full boost by like 3k!

To let you know... I'm not planning on boosting this to only 7-10 psi like a lot of people on here... I'm planning 23-25 psi which should net me close to 350 rwhp, if not more.

I'm thinking torque monster here

go to http://www.squirrelpf.com/turbocalc/

type in 2.4l engine.51 bsfc11.5 afr

7000 redline5500 max power3200 max boost2850 min boost

highlight the gt2871 56 trim .60 A/RCheck out efficiency ranges accross the powerband.

I'm probably going to go with a larger trim.... say like a 68 or 73

Modified by sorrowfulkiller at 6:28 PM 5/27/2009
Modified by sorrowfulkiller at 6:41 PM 5/27/2009

[DrifterProdigy85]

Do it if its what you really want. Saurus Garage or whatever there name is in Japan runs the Tomei ITB setup on there S15 Silvia. Seems like a badass setup but im not willing to pay the money for that. Ill stick to my 90mm TB on a SRI Manifold.

[sorrowfulkiller]

Do it if its what you really want. Saurus Garage or whatever there name is in Japan runs the Tomei ITB setup on there S15 Silvia. Seems like a badass setup but im not willing to pay the money for that. Ill stick to my 90mm TB on a SRI Manifold.

I would really like to do an ITB setup, i've always wanted to do one on something.... However I'm planning on doing a metric a**-ton of homework on it if I do plan on doing it.

I mentioned earlier about the engine analyzer pro program. It's extremely accurate, that being said I would probably have to get a lot of information on various parts of the stock KA24DE before I figure out the specifics for such a setup.

The main things I need to know first is...

How well the stock intake manifold flowshow large are the stock intake and exhuast portshow large the intake and exhuast valves are (diameter wise)

and that's pretty much all I need from there. I've got everything but that info...

Then I'll plug in that info, save it as a stock ka24de, then modify it with the gt2871 .68 turbo in the program. Then I'll just play with runner lengths and surge tank sizes til I get what I want.

As I've said before it will be a very thought out process, I'm going to be going for the most responsive and powerful powerband that I can run, and unless someone can make a evo3 16g (or preferably the hta68) compressor fit to a t3 twin scroll turbine housing then I'll stick with a gt2871 variant.

[Chaluska]

From what i understood, ITBs are partially cracked open, alot of people use the GTI-R or Hyabusa ITBs.

As far as brake booster. that 4 port vaccum block sounds like the right idea, but man, talk about alot of vaccum lines.

But doing that, i suppose you would be able to hook up your boost gauge / Brake booster / FPR.

[sorrowfulkiller]

From what i understood, ITBs are partially cracked open, alot of people use the GTI-R or Hyabusa ITBs.

As far as brake booster. that 4 port vaccum block sounds like the right idea, but man, talk about alot of vaccum lines.

But doing that, i suppose you would be able to hook up your boost gauge / Brake booster / FPR.

It seems I'll be looking for GSXR ITB's and aftermarket Velocity stacks for them that are metal. I read a diy ITB setup using these GSXR ITB's and he just played with a screw to set the idle.... so good for me!

The vacuum block idea would be quite easy to do, I would have the vacuum block attached to the runners on some sort of bracket, minimizing mess while still retaining a good place to get a vacuum source.

I thought about a pre turbo vacuum fitting for the brake booster but damn that'd be really touchy while in boost xD

I would think the hardest part of such a part would be figuring out what kind of taper to build into the intake runners so they promote good mach numbers out of boost

[sorrowfulkiller]

So after doing a little research on the t25 flange and inputting the information into engine analyzer pro... I have found out that t3 will be te way to go....

I'm going to go with a ATP turbo with a GT2876R Compressor, and a T3 turbine housing, and get a downpipe made.

The program showed the t25 to be a major restriction past 4k, it was making only about 350 hp at 5000 and 360 lb/ft of torque at 3000. The T3 flange however would make 408 hp at 5500 and 444 lb/ft of torque at 3000.The T3 flange proved to be a much wider powerband also, whereas the t25 would hit boost like a motherf***er but then it would just lose power just as fast.

I forgot, btw both of these were at 23.5 Psi
Modified by sorrowfulkiller at 10:46 PM 5/28/2009

[wrxratd]

stick a t3 twin scroll 3071r turbo into your analyzer and see what you come up with. You mentioned earlier you were looking into evo3 16g or the hta68 compressor wheels. The hta outflows the 16g by about 8 lbs/min (according to forced performance) but the hta and the 3071 wheel flow pretty much the same amount. right around 47 lbs/min... I just realized you probably already know this...

[sorrowfulkiller]

lmfao, Yeah I could go with a 3071, but Personally I've always gone by the idea that one should figure out what kind of turbo you use based off of what your horsepower goals are.

I may have to look into putting the 3071 into the program to check out what the numbers on that would be around. Because it looked like in the power area that I'm looking at, that the 3071 would be more efficient. I always like hearing other people thoughts on something... gives a better perspective on things, that and I've always thought, go by what people who know the car know about the subject.

So turbo is still up in the air xDIf only they made a HTA 3071 I'd be happy xD

btw the program I'm using is extremely accurate, many engine builders use it to figure out what kind of powerband to expect fom a modification on a car, or to develop different parts. Only bad thing is that it's $479 O_o I didn't pay for it though xD

EDIT::

I just noticed you have a wrx, anything done to it? Have any issues with the trans? My 2nd gear just exploded last week I want to get rid of it because I don't want to have a DD break down because of mods... it sucks when you can't go anywhere because your tactrix cable won't connect to the car and you just installed 800cc injectors

[sorrowfulkiller]

btw, does anyone other than full race make a twin scroll manifold for the ka24de?

[sunnys14]

Nope. There aren't very many turbo manifolds for the KA.

[sorrowfulkiller]

Nope. There aren't very many turbo manifolds for the KA.

Well that blows... if I had any experience with welding I'd make a manifold up myself... sadly I don't.

[480sx]

Full race or (god i hate to say it) AMS for your top quality manifolds. I choose AMS because i like the bottom mount design for weight distribution.

The full race manifold is incredible, if i had the cash i would def buy one for my other project.

[sorrowfulkiller]

i didn't see any manifolds listed at the ams website for the ka24de... where are you looking at?

[480sx]

? I have one. Last time i checked they brought them back for 800 dollars and it was up on their webpage. If ur interested you should contact them.

[sorrowfulkiller]

can anyone measure the lengths of the stock ka24de intake manifold and give me a rough idea of about what the inside diameter is on them?