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Cons of ITB's

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11K views 35 replies 18 participants last post by  4 Throttle Tuning  
#1 ·
What are the cons of having ITB's, do they make the car more unreliable, ok for a daily driver? What about rain, what do you do? Cold weather and hot, any differences? I hear they make fires easy to start? Thanks!

Simon
 
#2 ·
If tuned right... there is no downside. As with any performance mod, you will use a bit more fuel when driving hard... as more power typically requires more fuel.

Filtering them is always wise though... but that does hurt their performance.... so you do need to decide on that... for a street car I'd personally never go filterless.
 
#10 ·
Any trouble with stumbling at part throttle? I noticed when I drove Jimmy's car that it would stumble at part or off throttle once under way. I think Jimmy had explained that the hardware setup was not the same as would be used in a daily driver car, though--the issue doesn't really matter if you spend all your time on the throttle like he does!
 
#11 ·
Any trouble with stumbling at part throttle? I noticed when I drove Jimmy's car that it would stumble at part or off throttle once under way. I think Jimmy had explained that the hardware setup was not the same as would be used in a daily driver car, though--the issue doesn't really matter if you spend all your time on the throttle like he does!
That is poor tuning and possibly a sync issue. A properly tuned setup... should drive like factory... with a bit more ooomph.
 
#12 ·
Any trouble with stumbling at part throttle? I noticed when I drove Jimmy's car that it would stumble at part or off throttle once under way. I think Jimmy had explained that the hardware setup was not the same as would be used in a daily driver car, though--the issue doesn't really matter if you spend all your time on the throttle like he does!
That is poor tuning and possibly a sync issue. A properly tuned setup... should drive like factory... with a bit more ooomph.
Exactly. I think that was back when Jimmy was using the Freedom ECU and not the AEM so his tuning time was somewhat limited since the whole thing is in Japanese and sorta hard to find a tuner around these parts that knows Japanese :lol:

But in answer to the OP's question, The only cons I can think of is slightly higher fuel consumption and the need for a aftermarket engine management solution to make it run not only properly, but also effeciently. It's like Splitime said, a PROPERLY TUNED setup should be as transparent as a factory setup with maybe only a minimal hit to mpg. Having ridden in and driven many different setups (including different ITB installs) I can safely say that the best ones were those that were using a full engine management solution and had extensive dyno time to tune out any and all issues within the power curve.

The best thing you can do with ITBs is have several different settings for the ECU to use. Something like street, race, emmissions :p, cruising, and WTF HOLD ON :lol:

Having different tunes to comply with the driving you're going to be doing will not only help with the drivability on the street but also make the car more fun to drive in whatever situation you're going to be driving it in. It doesn't make sense to be using a full race tune on the street nor using a street tune on the track.

As far as maintaining them, yes, there is a little upkeep. Though not nearly as much with a carb setup. Most ITB units have locking bleed setups on them so there is very little adjustment, if any, to be done after the initial tuning and syncing. Running some type of filtration on the streets is reccommended simply because of all the crap floating around.

There are many debates on what works the best, but most seem to end in saying that the filter socks inhibit fllow the most, and the larger single filters flow the best.
 
#15 ·
Why would it backfire out the hornes, and if it does what happens? Fires? I am not looking for crazy HP numbers, the car is for autocross and track days, but is my daily driver basically.

Another question, what is a vaccum box? I am looking at piecing together my own DIY kit, I have lots of motorcycle friends I can get throttle bodies cheap.
 
#16 ·
If you dont know what the vaccum box is for, it looks like piecing together your own kit may not be such a good idea. Also, youll most likely come out cheaper and less issues by buying a kit thats already assembled like Rs Aizawa, Fuji Racing etc. I dont mean to sound like a turd btw :)
 
#17 ·
iv had the fujiracing setup on my car for allmost 2 years now..

(i probaly have the most miles on a miata with jimmys kit)

i drive the car everyday!
that in the rain, snow, ice, construction, summer, racing ect,
NEVER have used anytype of filter
it does use more fuel but not that much if your driving normal
it sounds amazing

once you get them on the car and adj.ed right you donk need to adj. them again. (unless you did somthing wrong)
you will be adj.ing the ecu more than the manifold, unless you get it dyno tuned by a certified tuner (witch is the best way to go)

itb>turbo!!!!!!!!!!!!!!!!!!!!!!!!!

people need to stop comparing itb's to turbo, there completely different

itbs work fine w/ a stock motor but when you add cams, higher compression, or head work it amplifi's the preformance and power. u can make power w/ itbs but it will not come from just bolting them on!!

im done ranting
 
#18 ·
If you dont know what the vaccum box is for, it looks like piecing together your own kit may not be such a good idea. Also, youll most likely come out cheaper and less issues by buying a kit thats already assembled like Rs Aizawa, Fuji Racing etc. I dont mean to sound like a turd btw :)
I just always like DIY projects, piecing everything together over time, then when I have it all putting it on the car. Only one way to learn lol
 
#20 ·
Any trouble with stumbling at part throttle? I noticed when I drove Jimmy's car that it would stumble at part or off throttle once under way. I think Jimmy had explained that the hardware setup was not the same as would be used in a daily driver car, though--the issue doesn't really matter if you spend all your time on the throttle like he does!
That is poor tuning and possibly a sync issue. A properly tuned setup... should drive like factory... with a bit more ooomph.
Exactly. I think that was back when Jimmy was using the Freedom ECU and not the AEM so his tuning time was somewhat limited since the whole thing is in Japanese and sorta hard to find a tuner around these parts that knows Japanese :lol:
You're right. It just highlights the need to have it properly tuned. Jimmy does know Japanese, tho ;)
 
#21 ·
The only disadvantage i've found is the "you have to tune it" part of things. Beyond that, once it's tuned it should be bulletproof... but until then, i'm trying not to drive it. A poorly tuned setup will be a constant headache. That's the only downside to me so far.
 
#22 ·
I could think of quit a few, and I would have pointed out the same about for turbo as well.

- The money you pay for the power you get!
- ITB is only a small part of the power forumla, there is alot of thing that need to accompany it for power.
- Damn fuel smells... and watch out for backfire out of the hones!
- Irrelevant. ITBs aren't about balls-out power, they're about throttle response and improved air/fuel delivery to the cylinder
- The same is true with any other induction modification. If you get a turbo setup you'd be stupid to retain the stock exhaust, so it's a no-brainer there.
- But that's part of the charm of them! :lol: Plus when they bark at people (Peter) trying to blip the throttle too much it acts as a security measure :lol:

How much power is actually gained?
On a stock motor with a better exhaust you'd be looking at about 15hp and about that much torque if not more. I managed to spin the tires from a stop when my foot slipped off the clutch at a stoplight I was feathering it at 2000rpms at the car didn't stall out.

Why would it backfire out the hornes, and if it does what happens? Fires? I am not looking for crazy HP numbers, the car is for autocross and track days, but is my daily driver basically.

Another question, what is a vaccum box? I am looking at piecing together my own DIY kit, I have lots of motorcycle friends I can get throttle bodies cheap.
Basically you have straight tubes going into your cylinders now. You wouldn't notice it on a stock car because of the plenum the manifold has on it. But if you take off the manifold you'll see it's pretty scorched on the inside from little spits and coughs. Fires are a danger, but a small one if the work is done right. The main thing to be sure about is that ALL your fittings are secure and leak-free, especially fuel lines.

Vacuum box (or log) just creates a vacuum source for other vacuum related systems in the car to run off of (brake booster, cruise control, MAP sensor, etc). Since you remove the plenum of hte stock manifold it's suggested you get one with an ITB setup to help distribute the flow again.

Exactly. I think that was back when Jimmy was using the Freedom ECU and not the AEM so his tuning time was somewhat limited since the whole thing is in Japanese and sorta hard to find a tuner around these parts that knows Japanese :lol:
You're right. It just highlights the need to have it properly tuned. Jimmy does know Japanese, tho ;)[/quote]

Yeah, but he doesn't know tuning all that well. Having to try and describe what certain features are from another language is very difficult. When I was working with my friend to try and translate some stuff for a GReddy controller there was stuff I had to really scratch my head over trying to figure out what it would be in english :lol:
 
#26 ·