Individual Throttle Bodies and Improved Airflow

[Dessertrunner]

I need advise as the best way to go about finding out if they are of any benfit so these are the changes I am doing to the engine to make it produce more power.
- Currently it has 11.1 and as I understand cams are 152 on both (correct me if I am wrong please mike)
- Wolf ECU
- Extractors
- 550cc injectors
- Multipass radiator for cooling probelm.

Then throttle bodies

So I was planning doing everything except the the last getting maxium power up to that point and dyno it. Hopfully on the same day unbolt the existing intake and replace with the ITB and redyno. If there is a gain then try to improve this if not look at why.

Does this seem like the right way to go?
Tony

[Boxersix]

Originally Posted by Dessertrunner

I need advise as the best way to go about finding out if they are of any benfit so these are the changes I am doing to the engine to make it produce more power.
- Currently it has 11.1 and as I understand cams are 152 on both (correct me if I am wrong please mike)
- Wolf ECU
- Extractors
- 550cc injectors
- Multipass radiator for cooling probelm.

Then throttle bodies

So I was planning doing everything except the the last getting maximum power up to that point and dyno it. Hopfully on the same day unbolt the existing intake and replace with the ITB and redyno. If there is a gain then try to improve this if not look at why.

Does this seem like the right way to go?
Tony

Well the best thing to do is A) determine what you consider a benefit, and B) Determine where you want to make power(torque under curve). Locking down those two factors you can then do some calculations that will aid you in building an ITB setup that best suits what you're looking to get out of it.

High performance engines that come with OE ITB's tend to have some method of making up for torque loss, either in high compression(11.5+) or forced induction. A prime example of the NA motor would be the BMW S54 @ 11.5:1 with dual VANOS, while a prime example of an ITB boosted engine would be the RB26DETT from the GTR's. You shouldn't have a problem with 11.1.

Most "bolt on", non engine-setup specific style ITB systems from your typical "tuner" shop tend to be REALLY peaky in that they tend to make more power but the area under the curve is next to nothing. They're thinking exactly along the same lines as you, that bolting on ITB's is going to instantly add power. In some instances this is true, however unless it's fully tuned for the EXACT setup of your particular engine, there are going to be sacrifices and/or losses elsewhere in the system.

This is mostly due to the generic and most basic production of these kits. They're meant to fit a motor with a broad range of variables(port tapers and valve profiles, cam profiles, disp, RPM cap, etc, etc) where in fact all those plus more are variables used to MAKE the specific ITB for the motor it's meant for.

The basic math isn't hard. Most people just get flustered by formulas and think they cannot crunch the numbers to get it right.

As far as being able to swap intake systems right on the dyno and expecting to make some clean pulls with reliable numbers realistically won't happen. The two setups are going to require some changes in the tune right away, how drastic really depends on the swapped setup and how the car is tuned prior. Tuning ITB setups by Alpha N/TPS input always tends to works out better(in my experience), although speed density with a proper vacuum chamber can be done pending on vacuum production. The problem with using speed density isn't so much the lack of a signal from the ITB's, but rather a wave pulse signal(on/off) as each cylinder applies it's work to the chamber.

As usual I'm overly swamped here at the shop with projects galore, but I am still working on an ITB system for the EG33. It was destined to be in my 962, but that idea was scrapped when I set forth to develop and entire V12 engine from scratch for the chassis. Being in the WRX now I still have some desire to go high comp NA with it after watching Lavery's ST2 car on the dyno @ EFI Logic, and as such will still put the effort into making ITB's at some point. It's going to be specific to my future build and wouldn't be of much use to someone such as yourself. However, I do believe that with the aid of myself and a few members here such as OAB_AU, we can get you into a much better ballpark and likely still meet your requirements(fitment, swap easy, etc, etc)

I've made alot of ITB conversion and I've made some serious duds in the past, wasting alot of time and money. This is my main reasoning behind trying to assist people such as yourself, so you don't waste valuable time and money and get discouraged in the process.

[Dessertrunner]

So Adam were do I head next and what formuli do I need.
Tony

[oab_au]

I got to agree with Adam.

I could see the point of IVTs, if it was going in a car that could have the 6 intakes sticking up through the hood. They could all be drawing cold air, at a new resonate length that would allow the torque to be developed at a higher rpm.
With them under the hood, you need to provide filtered, cool air to them. This means that you have to connect them to some sort of air duct to outside the engine compartment, which will defeat the point in having them. As the ducting will interfere with the resonate length, and the three cylinders will be robbing each other of air.

The only difference in having the butterflys near the cylinder is to shorten the response time of the air flow to accelerate. Using a plenum mounted throttle body, and all the intake pipes running off it, can produce the same results.

I think you may have got to wrong idea about the standard plenum set-up, from what you said here, this wasn't caused by a vacuum, it was the sound waves :

When you see what happened to Rally Bob's intake under vacuum it is hard to not come to the conclusion that that engine was starving for air in spite of all the understanding that the throttle body is big enough.

I commend Bob for doing it, the only thing was the sheet was a bit thin, and the resonate waves pounded the shlt out it, and lost some energy doing it. I have had expansion chambers on two stroke shatter the whole chamber surface, because we tried to save weight on the metal. The energy contained in these sound waves is quite high. I would dearly love for him to do another one with shorter tracts to raise the resonate frequency to 6000 rpms.

As I have said before, the object of the excesses is to give a broad torque curve that makes the car easier to drive fast. Producing high peaky power can make it undriveable. Fine for a drag car but doing the Targa is a lot different.

I think the best you can do is to rework the standard manifold to shorten the tracts, or build another. Also build a shorty exhaust that has the branches 4" longer, to prevent cylinder interfenance from the longer duration exhaust cams. With the overall length shortened to raise their resonate point to 6000 rpm. The pipes then have to enter a two in, cat, chamber, etc, to expand like they were the end of the pipe.

Harvey.

[Dessertrunner]

I am working on the exhaust as well Harvey so I will take your point on board. I think that we will stiil see some gains. If you look at some of the set ups on the Autospeed story it was still worth having ram pipes with a plenum chamber as long as it was feed well.
The good thing about the discussion is that it creates thought and that is great. The way I see it is that if you had a shopping list to get maxium power you would have sort out the ITB problems at some point. So I will give it a go.
Tony

[svxfiles]

Originally Posted by Dessertrunner

I am working on the exhaust as well Harvey so I will take your point on board. I think that we will stiil see some gains. If you look at some of the set ups on the Autospeed story it was still worth having ram pipes with a plenum chamber as long as it was feed well.
The good thing about the discussion is that it creates thought and that is great. The way I see it is that if you had a shopping list to get maxium power you would have sort out the ITB problems at some point. So I will give it a go.Tony

Good for you!
And good for us as well!
The more that people actually do,
(rather than just talk about doing,)
the more that gets done!

[svxfiles]

Originally Posted by oab_au

I got to agree with Adam.

I could see the point of IVTs, if it was going in a car that could have the 6 intakes sticking up through the hood. They could all be drawing cold air, at a new resonate length that would allow the torque to be developed at a higher rpm.
With them under the hood, you need to provide filtered, cool air to them. This means that you have to connect them to some sort of air duct to outside the engine compartment, which will defeat the point in having them. As the ducting will interfere with the resonate length, and the three cylinders will be robbing each other of air.

The only difference in having the butterflys near the cylinder is to shorten the response time of the air flow to accelerate. Using a plenum mounted throttle body, and all the intake pipes running off it, can produce the same results.

I think you may have got to wrong idea about the standard plenum set-up, from what you said here, this wasn't caused by a vacuum, it was the sound waves :



I commend Bob for doing it, the only thing was the sheet was a bit thin, and the resonate waves pounded the shlt out it, and lost some energy doing it. I have had expansion chambers on two stroke shatter the whole chamber surface, because we tried to save weight on the metal. The energy contained in these sound waves is quite high. I would dearly love for him to do another one with shorter tracts to raise the resonate frequency to 6000 rpms.

As I have said before, the object of the excesses is to give a broad torque curve that makes the car easier to drive fast. Producing high peaky power can make it undriveable. Fine for a drag car but doing the Targa is a lot different.

I think the best you can do is to rework the standard manifold to shorten the tracts, or build another. Also build a shorty exhaust that has the branches 4" longer, to prevent cylinder interfenance from the longer duration exhaust cams. With the overall length shortened to raise their resonate point to 6000 rpm. The pipes then have to enter a two in, cat, chamber, etc, to expand like they were the end of the pipe.

Harvey.

Harvey!
You just gave me an idea!!!
PM coming.

[Trevor]

Originally Posted by oab_au

With them under the hood, you need to provide filtered, cool air to them. This means that you have to connect them to some sort of air duct to outside the engine compartment, which will defeat the point in having them. As the ducting will interfere with the resonate length, and the three cylinders will be robbing each other of air.

Not necessarily, as long as the duct has a cross section exceeding that of combined intakes, by a good margin.

[Dessertrunner]

To continue interest here is a F1 cut engine, has rotary throttle body.
Tony

[Boxersix]

Originally Posted by Dessertrunner

To continue interest here is a F1 cut engine, has rotary throttle body.
Tony

Roller throttles, without some form of advanced FEA and sculpting, tend to be quite a bit larger in overall body size than a comparable butterfly valve. It's just due to the size needed to house the roller that provides unobstructed WOT and a completely closed off pot at idle in the same package. Aside from that, extensive tooling to make, and exceeding cost the roller throttles are fantastic. I've developed a few for various customer projects and am actually making a unit for a 700AWHP customer project car here this winter. Were talking $1500 throttle body's though(as in per throttle)

[Dessertrunner]

Got any photos?

[Boxersix]

Originally Posted by Dessertrunner

Got any photos?

I'll PM you one or two as long as you don't post them all over the net. The one I'll send you a CAD of is in the middle of some pat.pending processing and I just don't want everyone to see quite yet. It's going on a time attack chassis build here in the states for next season.....



Just PM'ed the links, please just follow my above request that's all

[Dessertrunner]

I will post the update in two parts. I have cut the intake manifold so I can build a new filter box to be feed from the bonnet scoop (which has its own problems). As you can see from the shoots I have opened up the front of the intake manifold so it is now part of the filter box to reduce any restrictions. Now I have to make the new filter box, the filter is 70% bigger then the current units we have in our cars.
Tony

[Dessertrunner]

Okay part 2, the planned location for the bonnet scoop will have a beam in the middle. If you look at the first image under the insulation in the centre is a strength beam. I think I may have to off set the filter to the side such as the second image. Any suggestion opinions greatly appricated.
Tony

[Dessertrunner]

They have been delivered here is a photo.

Tony