ITBs, fuel management, vacuum...
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ITBs, fuel management, vacuum...
With ITBs on a nonvtec daily driver (yes tuning and driveability will be a bitch), what would you suggest would be the best way to manage the setup. Its OBD1 with a PR4 ECU. With a budget in mind, would I be fine with a Hondata Stage 2A or would something like an SDS-efi or haltech or something else be the best way.
The ITBs I will be using will hookup to the stock TPS sensor & MAP sensor. How would I then provide sufficient vacuum for my brake booster? TIA
The ITBs I will be using will hookup to the stock TPS sensor & MAP sensor. How would I then provide sufficient vacuum for my brake booster? TIA
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Re: ITBs, fuel management, vacuum... (teg92)
Bump.
When the right person reads this heres another question. Through my research I hear some people say it is hard to get them to idle, but it is possible to hook up a IACV on them to get the ECU to get it to idle like a stock setup.
What exactly makes ITBs so much harder to get a good idle as long as you have proper MAP, TPS, and IAT readings? Is it because usually there is no IACV and the idle only comes from having the throttle plates slightly open? How do sport bikes maintain such good manners with ITBs and why is it so hard to adapt it to a street motor? The Toyota 4A-GE was a mass produced ITB engine, so its obviously possible.
When the right person reads this heres another question. Through my research I hear some people say it is hard to get them to idle, but it is possible to hook up a IACV on them to get the ECU to get it to idle like a stock setup.
What exactly makes ITBs so much harder to get a good idle as long as you have proper MAP, TPS, and IAT readings? Is it because usually there is no IACV and the idle only comes from having the throttle plates slightly open? How do sport bikes maintain such good manners with ITBs and why is it so hard to adapt it to a street motor? The Toyota 4A-GE was a mass produced ITB engine, so its obviously possible.
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Re: ITBs, fuel management, vacuum... (teg92)
I am in no way an expert, but what about runnin them on an afc-hack? Also, I have heard of people using a "vacuum canister" type of thing to store vacuum. I may be off, but I would like to know also.
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Re: ITBs, fuel management, vacuum... (Jeff C)
I beleive the ITB's get the map sensor values by adding the pressure from the 4 entries via "T"'s in vacum lines withing a chamber where the map sensor is hooked on, since the vaccum comes after the tb's it will get some partial values but since it's 4 independant values it's not like a precise 1 tb value thus being partially inacurate.. and yes.. no IACV can make that a bitch.....
i've been trying to read and understand but material is rare and not many people have it...
i've been trying to read and understand but material is rare and not many people have it...
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Re: ITBs, fuel management, vacuum... (HotWheelz-turboh22dx)
Yup, the ITB's I'm using are gonna have no problems feeding the stock MAP & TPS sensor. The IAT can be placed in front of the horns, so the only question is the vacuum canister & IACV....
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Re: ITBs, fuel management, vacuum... (teg92)
actually it can be outside, because theoritcally your taking ambiant air... you don't need to put it inside the runners to disturb flow and create turbulance.. mount it outside should be ok.. or put it tapered inside a runner so it won't hit the airstream... all AIT aren't in the airstream way.. for the IACV i know how to do that one, but that's my trick because i'm also using a prototype ITB setup, i have my manifold and everything ... using 54mm ITBS... no velocity stack's yet... i'll post mine once finished but i'm curious to see yours.. mine is all machined and tigged in aluminum... with a brushed aluminum finish...
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Re: ITBs, fuel management, vacuum... (Jeff C)
Have you guys read this thread?
Well it seems that the small 42mm TB's can work if someone can figure out how to determine optimum runner length for that size TB and optimum operating speed of the engine.
As for vacuum, its still just a matter of figuring out the design of the vacuum canister. Member CRX_VTEC claims to have built 4 working versions of the CBR929RR ITB's for use on a b-series head, but will not show anyone pics until they are sold.
I guess I'm on my own (probably like a few others) for designing this. I want to do it once and do it properly so I can feel confident that this will benefit the new motor I am building.
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Re: ITBs, fuel management, vacuum... (teg92)
That was a good thread, I thought. I wish that it could have kept going.
I am still trying to get my hands on a set of 929 itbs and then I will be in your position.
As far as vacuum canister, dont V8 guys have to use one when they have a really big cam? If so, it shouldnt be too hard to figure out. I just havent done too much research yet.
[Modified by Jeff C, 12:50 PM 12/16/2002]
I am still trying to get my hands on a set of 929 itbs and then I will be in your position.
As far as vacuum canister, dont V8 guys have to use one when they have a really big cam? If so, it shouldnt be too hard to figure out. I just havent done too much research yet.
[Modified by Jeff C, 12:50 PM 12/16/2002]
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Re: ITBs, fuel management, vacuum... (Jeff C)
As far as vacuum canister, dont V8 guys have to use one when they have a really big cam? If so, it shouldnt be too hard to figure out. I just havent done too much research yet.
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Re: ITBs, fuel management, vacuum... (HotWheelz-turboh22dx)
why won`t he release it... pictures... after all... it`s not everybody that has an aluminum welder and tools to rebuild the peice...
I wouldnt copy his cause I already now what I want to do. Besides, they will already look pretty much the same anyways.
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Re: ITBs, fuel management, vacuum... (HotWheelz-turboh22dx)
why won`t he release it... pictures... after all... it`s not everybody that has an aluminum welder and tools to rebuild the peice...
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Re: ITBs, fuel management, vacuum... (teg92)
These have got to be the best posts i've seen in a long time. More please! 
btw: Has anyone tuned a set of ITB's with an AEM system? Haven't seen anyone post on that yet.
btw: Has anyone tuned a set of ITB's with an AEM system? Haven't seen anyone post on that yet.
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Re: ITBs, fuel management, vacuum... (jg)
These have got to be the best posts i've seen in a long time. More please!
btw: Has anyone tuned a set of ITB's with an AEM system? Haven't seen anyone post on that yet.
btw: Has anyone tuned a set of ITB's with an AEM system? Haven't seen anyone post on that yet.
I still would like to learn more about part-throttle tuning, relationship between runner length and tb plate size in relation to bhp per cylinder, vacuum canisters etc... but have a feeling all the pros on this board are not going to see this thread.
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Re: ITBs, fuel management, vacuum... (teg92)
Some more fuel for the fire...
quoted from http://www.jenvey.co.uk (as well as featured on team-integra.net by fellow member Micheal Delany)
All would not be complete without eye candy.
some more candy...
[Modified by teg92, 7:36 PM 12/16/2002]
quoted from http://www.jenvey.co.uk (as well as featured on team-integra.net by fellow member Micheal Delany)
All would not be complete without eye candy.
<u>What is the best throttle body diameter?</u>
Factors influencing size are; Power output, RPM, cylinder head design, cylinder capacity, position of the throttle body in the inlet tract and position of the injector.
Choice of bore size is a balanced compromise resulting from the following;
1) A larger bore leads to lower flow resistance, but obeying the laws of diminishing returns.
2) A smaller bore leads to better throttle control and response (never underestimate) and improved fuel mixing.
3) The system should be considered in total - from (at least) trumpet flange to cylinder and proportioned accordingly.
Basic references for BHP per cylinder, assuming ca 120mm from butterfly to valve head and a max of 9,000 rpm are;
Up to 30 - 30mm, up to 33 - 32mm, up to 39 - 35mm, up to 46 - 38mm, up to 51 - 40mm, up to 56 - 42mm , up to 65 - 45mm, up to 74 - 48mm, up to 80 - 50mm, up to 87 - 52mm, up to 93 - 54mm.
These power figures may be increased by up to 10% in a purpose - designed, well proportioned system. As butterfly to valve distance increases, butterfly size will need to increase in proportion to system taper and vice versa. Lower revving engines and those with injectors placed before the butterfly will generally accept a larger body.
<u>What is the correct overall system length? </u>
Induction length is one of the most important aspects of fuelling performance engines.
In our experience an under-length system is the greatest cause of disapointment, with loss of up to 1/3 of power potential. There are a number of good books on the subject and the serious developer is referred to these and, in particular, dyno trials. A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional, i.e. for 18,000 RPM the figure is ca 175mm.
The induction system is part of a resonant whole - from trumpet to exhaust outlet - and the ideal length can be heavily influenced by the other components.
<u>Where is the best place for the injectors? </u>
For performance at low RPM, economy and low emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM as well as high speeds.
Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications.
Factors influencing size are; Power output, RPM, cylinder head design, cylinder capacity, position of the throttle body in the inlet tract and position of the injector.
Choice of bore size is a balanced compromise resulting from the following;
1) A larger bore leads to lower flow resistance, but obeying the laws of diminishing returns.
2) A smaller bore leads to better throttle control and response (never underestimate) and improved fuel mixing.
3) The system should be considered in total - from (at least) trumpet flange to cylinder and proportioned accordingly.
Basic references for BHP per cylinder, assuming ca 120mm from butterfly to valve head and a max of 9,000 rpm are;
Up to 30 - 30mm, up to 33 - 32mm, up to 39 - 35mm, up to 46 - 38mm, up to 51 - 40mm, up to 56 - 42mm , up to 65 - 45mm, up to 74 - 48mm, up to 80 - 50mm, up to 87 - 52mm, up to 93 - 54mm.
These power figures may be increased by up to 10% in a purpose - designed, well proportioned system. As butterfly to valve distance increases, butterfly size will need to increase in proportion to system taper and vice versa. Lower revving engines and those with injectors placed before the butterfly will generally accept a larger body.
<u>What is the correct overall system length? </u>
Induction length is one of the most important aspects of fuelling performance engines.
In our experience an under-length system is the greatest cause of disapointment, with loss of up to 1/3 of power potential. There are a number of good books on the subject and the serious developer is referred to these and, in particular, dyno trials. A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional, i.e. for 18,000 RPM the figure is ca 175mm.
The induction system is part of a resonant whole - from trumpet to exhaust outlet - and the ideal length can be heavily influenced by the other components.
<u>Where is the best place for the injectors? </u>
For performance at low RPM, economy and low emissions the injector needs to be close to the valve and firing at the back of the valve head. This is the favoured position for production vehicles.
For higher RPM (very approximately 8,000+) the injector needs to be near the intake end of the induction tract to give adequate mixing time and opportunity. The higher the RPM, the further upstream the injector needs to be. As a result, use of speeds above approximately 11,000 RPM may give best results with the injector mounted outside the inlet tract altogether (see our remote injector mounting). It is common to fit both lower and upper injectors in such a system to cover starting and low RPM as well as high speeds.
Where one injector is to be used per cylinder the best compromise position is immediately downstream of the butterfly. This gains maximum advantage from local turbulence and gives results surprisingly close to the optimum at both ends of the rev-range. This is the recommended position for most applications.
[Modified by teg92, 7:36 PM 12/16/2002]
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Re: ITBs, fuel management, vacuum... (teg92)
Wow, that was a good resource site for parts. Not sure if you looked at that neon guy's gallery, but here is the finished product...http://www.abdgraphics.com/iansite/ian2.html
You can see how he welded plates to the bottom of each tb in order to be able to mount them to the mani.
EDIT: Oh yea, there was a pic, but here is another.
[Modified by Jeff C, 8:13 AM 12/17/2002]
You can see how he welded plates to the bottom of each tb in order to be able to mount them to the mani.
EDIT: Oh yea, there was a pic, but here is another.
[Modified by Jeff C, 8:13 AM 12/17/2002]
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Re: ITBs, fuel management, vacuum... (Jeff C)
TWM advises disabling your MAP sensor and using TPS for fuel data.
But Skunk2 has TWM individual throttle bodies on their street car and are running it with a chipped ECU and an AFC. Try asking them I suppose.
Or you could do it the REALLY easy way. Get an AEM EMS. Then get a MAF sensor. Bing!
[Modified by qtiger, 9:27 AM 12/17/2002]
But Skunk2 has TWM individual throttle bodies on their street car and are running it with a chipped ECU and an AFC. Try asking them I suppose.
Or you could do it the REALLY easy way. Get an AEM EMS. Then get a MAF sensor. Bing!
[Modified by qtiger, 9:27 AM 12/17/2002]
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Re: ITBs, fuel management, vacuum... (Jeff C)
You can see how he welded plates to the bottom of each tb in order to be able to mount them to the mani.
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Re: ITBs, fuel management, vacuum... (teg92)
I moved my post from the other thread...
teg92, the gsxr 750 tbs are 42mm as opposed to the 40mm 929 ones. Either set will be good for me. If those 4A-GE ones are 50mm, then that will be way too big.
As far as overall system lenght. That site says...
...so for an 8000rpm motor the face of the trumpet to the center of the valve head should be 393.75, correct? How am I going to measure to the center of the valve head with the head and oem im assembled and in the car? I guess it doesent have to be that accurate. Now the runner lengths will vary depending on the trumpet lengths, and shorter runners equal topend power and longer runners equal lowend power. Now I have to think of where I want my power.
As far as the map probs, my crx already has a vacuum type canister for the map sensor, correct? So I would just have to run a line to it from the runners, correct? That should take car of the surging vacuum the the ITBs create.
A lot to think about. Am I just way off?
teg92, the gsxr 750 tbs are 42mm as opposed to the 40mm 929 ones. Either set will be good for me. If those 4A-GE ones are 50mm, then that will be way too big.
As far as overall system lenght. That site says...
A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional, i.e. for 18,000 RPM the figure is ca 175mm.
As far as the map probs, my crx already has a vacuum type canister for the map sensor, correct? So I would just have to run a line to it from the runners, correct? That should take car of the surging vacuum the the ITBs create.
A lot to think about. Am I just way off?
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Re: ITBs, fuel management, vacuum... (Jeff C)
Jeff C... a reply to your other post....
CBR929RR = 40mm
GSXR750 = 42mm
CBR954RR = 43mm
Toyota 4A-GE = EDIT43mm (not 50mm)
Haybusa GSX-1300 = 46mm
I've gone with the CBR954RR, I don't yet physically have them but they're on the way. I chose them to try to simply things regarding sensors. The 4A-GE were designed for a 1.6L, so the whole 50mm seems a little large. The Toda kit is apparantly the toyota ITBs with their own cast manifold.
The relationship for overall length and rpm range seems to be linear, so that calculation seems fine. I put together a little chart to make it easier for people to interpret the relationship.
For some reason I feel like when ITB specialists are talking about optimizing high end power, they are emphasizing high end power a lot more than we should be, so I would add another lets say 20mm to whatever seems right to this scale.
As for the vacuum canister, I am not sure of why your CRX would already have a vacuum canister. To my understanding all honda MAP sensors just get a reading from the vacuum off either a TB or outlet on the intake manifold. By combining all 4 outlets off each TB, you should theoretically end up with similiar vacuum readings... The problem is giving enough vacuum to your brake booster without upsetting your idle...
[Modified by teg92, 7:11 PM 12/17/2002]
CBR929RR = 40mm
GSXR750 = 42mm
CBR954RR = 43mm
Toyota 4A-GE = EDIT43mm (not 50mm)
Haybusa GSX-1300 = 46mm
I've gone with the CBR954RR, I don't yet physically have them but they're on the way. I chose them to try to simply things regarding sensors. The 4A-GE were designed for a 1.6L, so the whole 50mm seems a little large. The Toda kit is apparantly the toyota ITBs with their own cast manifold.
The relationship for overall length and rpm range seems to be linear, so that calculation seems fine. I put together a little chart to make it easier for people to interpret the relationship.
For some reason I feel like when ITB specialists are talking about optimizing high end power, they are emphasizing high end power a lot more than we should be, so I would add another lets say 20mm to whatever seems right to this scale.
As for the vacuum canister, I am not sure of why your CRX would already have a vacuum canister. To my understanding all honda MAP sensors just get a reading from the vacuum off either a TB or outlet on the intake manifold. By combining all 4 outlets off each TB, you should theoretically end up with similiar vacuum readings... The problem is giving enough vacuum to your brake booster without upsetting your idle...
[Modified by teg92, 7:11 PM 12/17/2002]
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Re: ITBs, fuel management, vacuum... (teg92)
Here is my post from the other thread...
teg92, the gsxr 750 tbs are 42mm as opposed to the 40mm 929 ones. Either set will be good for me. If those 4A-GE ones are 50mm, then that will be way too big.
As far as overall system lenght. That site says...
...so for an 8000rpm motor the face of the trumpet to the center of the valve head should be 393.75, correct? How am I going to measure to the center of the valve head with the head and oem im assembled and in the car? I guess it doesent have to be that accurate. Now the runner lengths will vary depending on the trumpet lengths, and shorter runners equal topend power and longer runners equal lowend power. Now I have to think of where I want my power.
As far as the map probs, my crx already has a vacuum type canister for the map sensor, correct? So I would just have to run a line to it from the runners, correct? That should take car of the surging vacuum the the ITBs create.
A lot to think about. Am I just way off?
teg92, the gsxr 750 tbs are 42mm as opposed to the 40mm 929 ones. Either set will be good for me. If those 4A-GE ones are 50mm, then that will be way too big.
As far as overall system lenght. That site says...
A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional, i.e. for 18,000 RPM the figure is ca 175mm.
As far as the map probs, my crx already has a vacuum type canister for the map sensor, correct? So I would just have to run a line to it from the runners, correct? That should take car of the surging vacuum the the ITBs create.
A lot to think about. Am I just way off?
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Re: ITBs, fuel management, vacuum... (teg92)
How are you coming up with those numbers? My math must be off.
You may be right. All I know is that my map sensor is on the firewall unlike the newer car that have the map directly on the tb. A vacuum line runs from the tb > a black canister (not sure its function) then > map sensor on the firewall. I'll have to look up its function tonight.
As for the vacuum canister, I am not sure of why your CRX would already have a vacuum canister. To my understanding all honda MAP sensors just get a reading from the vacuum off either a TB or outlet on the intake manifold.
I'll have to look up its function tonight.
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Re: ITBs, fuel management, vacuum... (Jeff C)
How are you coming up with those numbers? My math must be off.
You may be right. All I know is that my map sensor is on the firewall unlike the newer car that have the map directly on the tb. A vacuum line runs from the tb > a black canister (not sure its function) then > map sensor on the firewall. I'll have to look up its function tonight.
You may be right. All I know is that my map sensor is on the firewall unlike the newer car that have the map directly on the tb. A vacuum line runs from the tb > a black canister (not sure its function) then > map sensor on the firewall.
I'll have to look up its function tonight.
My car as well has the MAP sensor on the firewall, its an OBD1 integra. Like I said I will get really deep into this once I get them in my hand.