[chetanhanda]

Originally Posted by shazikon

Chetan it would help if you could be more straightforward and explaind if you knew

relax dude its a harmless question, I need to 1st know what he has under the hood, so thats my 1st question.Let him answer then we can go ahead from there.
and what are you getting at by saying "and explained if you knew"

Originally Posted by shazikon

Pros and cons it doesnt matter what anyone has under their hoods

why are you so sure that it doesn't matter ?
of course it matters.. TB with combined with what other mods is a valid question...

[manveet]

Originally Posted by rohan_fonseca

What exactly is done to enlarge a throttle body? Is it an effective mod on the zen?

Originally Posted by chetanhanda

depends on what else u got there under the hood...
so what you got ?

Well Chetan, to answer the first part of his question (quoted in bold), one doesn't need to know what he's got under the hood.

-----

Originally Posted by rohan_fonseca

Chetan it would help if you could be more straightforward and explaind if you knew..

Exactly.

Chetan - what Rohan is politely saying is that if you know it then explain else go complicate some other thread.

Originally Posted by rohan_fonseca

what really happens in TB enlargement and and what other enhancements are required to make it effective.

Here goes, he's repeated the question once more for your understanding.

And my Dear Chetan, here is my Message to you, just like Elf also pointed out earlier - with your infinite knowledge of Automobiles, there are 2 Reasons for you to be on this thread:

1. As a part of the Solution.
2. As a part of the Problem.

You know what you've been upto lately. So I sincerely request you to contribute more constructively to this forum. If you are feeling the need to correct peoples English on T-Bhp, you need to grow up my friend.

Originally Posted by chetanhanda

and what are you getting at by saying "and explained if you knew"

[Ford Rocam]

If you happen to see any stock T.B it will look similar like this, when you say you oversize t.B you actually increase the stock diameter of the Butterfly inside the T.B, the butterfly is removed from the body & is replaced by a larger diameter butterfly, the size is limited to max boring which can be done inside the throttle body to accomodate the larger diameter butterfly.

Weather you will gain or loose power by doing this is another story my take on this is that if your engine combination downstream doesn't flow more air/cfm then a larger T.B wont help infact in same cases it can reduce performance cause when you increase diameter you are increasing the volume but you are reducing the velocity which can hurt performance.

as an eg: a stock B16A produces 170HP where as an stock B16B Type-R motor produces 185HP but the T.B is same for both the engine.
Not all engines will benefit by oversizing t.b, its not that like 1 size fits all the results can vary from engine to engine.

also the TPS has to recalibrated for oversize T.B or else you will face problem in idling and weird engine response in case if you replace entire T.B with bigger one.

[elf]

Finally, some light.

Thank you Jitu-sahaab.

[Ricky_63]

Hi

Just curious....I got my Lancer's throttle body increased from stock which I think is 48 mm to 53 mm (figures from my tuner friend). In addition I have a Conical Greencotton Filter, Custom Headers, FFE, Iridium Plugs & 9mm cables from distributor to plugs (dont know the name) What increase in BHP should I realistically expect ??

Informed comments welcome

Thanks in advance

[manveet]

@ FR

What's the expansion one can expect in an OHC, in terms of mm?

From what you said, I understand the the Butterfly Valve has to be replaced. Is that the only change that takes place, or is some shaving also involved elsewhere in the TB?

Regards

[Ford Rocam]

@ Ricky 63, with mods u listed if done correctly,expect anywhere between 7-10bhp.

@manveet I have never done t.b of ohc, your local turner only will be able tell it exactly, usually its 2-3 mm over stock. When u replace butterfly with bigger one the inside of T.B has to bored out to accomodate bigger size butterfly (i have mentioned that earlier) but theres a limition to boring inside T.B
but.....Dont waste money on overboring stock OHC T.B just replace it with JDM D15 T.B its bigger & better & if your pocket permits get a JDM D15 manifold as well for OHC, you will see phenominal gains & your OHC will love this.

[Ricky_63]

[quote=Ford Rocam;424535]@ Ricky 63, with mods u listed if done correctly,expect anywhere between 7-10bhp.

Just 7-10 bhp ????? I was given to understand a much bigger gain . Well thanks anyways.

Cheers

[chetanhanda]

Rocam's explained pretty well what is done in TB enlargement, thats a nice diagram.

If I may add some more..
Upsizing the TB helps if you actually require the much needed additional airflow, it would be crtical if you have increased the VE by means of cam duration/lift, porting/polishing, valve angle job, forced induction etc
If you are running a stock engine under the hood it would be an overkill to upsize TB (assuming the OEM TB was not very severly restricted).
You would only end up with a very sensitive throttle depending on your upsize, because of the extra air. For e.g. If the same TB is ported you would possibly get the same stock power only at a lower throttle position, maybe a few gains at WOT.
(We were discussing this on another thread also http://www.team-bhp.com/forum/techni...tml#post421785)

[payam]

one question:
size of enlargment is vary from car to car?and what will happend if we make mistake on that?

[Ricky_63]

[quote=Ford Rocam;424535]@ Ricky 63, with mods u listed if done correctly,expect anywhere between 7-10bhp.

Sorry I also have porting & polishing in addition to the other things I stated....does that change the BHP +++

Thanks

[shazikon]

Should one increase the size of the injector or is the stock one sufficient??
@chetan, i respect your knowledge but your questions were irrelevent when we were discussing TB enlargement in general. hence my remarks.. i guess Manveet has put in exactly my thoughts in response.

[manveet]

Originally Posted by chetanhanda

If I may add some more..

Yes, you most certainly may. However, your points in the quoted post are more in line with effect of TB expansion rather than than how it is done.

Anyhow, taking this further - for sake of discussion, lets talk about my OHC.

Originally Posted by chetanhanda

Upsizing the TB helps if you actually require the much needed additional airflow, it would be crtical if you have increased the VE by means of cam duration/lift, porting/polishing, valve angle job, forced induction etc.

Yes, on the intake side I have a Conical filter and have removed the catalytic converter etc. for the free flow exhaust which includes headers tuned for mid-range.Am also going in for a port-polish job shortly.

Now tell me this - what is the effect of TB expansion in case of my ride, considering the fact that I've already done a few things here and there that have improved the breathing aspect.

p.s.
please remember that we are talking about a car that is 100bhp in stock form, its not like a 220 bhp engine where marginal tweaking would lead to greater absolute gains.

[chetanhanda]

Originally Posted by payam

one question:
size of enlargment is vary from car to car?and what will happend if we make mistake on that?

TB mod on its own cannot do so much damage in the same way it cannot get so much gains by itself, it needs a corresponding uprated intake sytem to make a diff.
If you make a mistake regarding the size like making it very large ... it wont do any damage ,just that your car will jump even for a slight throttle input.
Also consider this e.g if you go to the crazy extreme end with a large TB and intake sytem you may generate some MAP readings for which the stock ECU may not have a corresponding value of Injector pulse on the fuel map. You may go into open loop and even possibly run lean with extremely high damaging EGT, but im sure you wont be going that extreme with just a TB mod.
Or even if you use a reflashed ECU/piggyback to compensate for extra air then your stock injectors may not be able to handle the the extra fuel, , but im sure you wont be going that extreme with just a TB mod.

if you should worry about something..worry abt the rest of the intake system and how you are going to port match your TB to your system.

[chetanhanda]

Originally Posted by shazikon

Should one increase the size of the injector or is the stock one sufficient??

hey shazikon.. dont worry about the injectors after just changing the TB size.
Think of it this way - if your "litres per hour" is uprated and if you get an uprated fuel pump and FPR in order to compensate for extra air and are using a standalone EMS,piggyback EMS or piggback fuelcontroller and are in process of changing the base fuel maps then the Injector size needs to be considered.Again the stock injectors may suffice till you dont max out their rated duty cycle.

Originally Posted by shazikon

@chetan, i respect your knowledge but your questions were irrelevent when we were discussing TB enlargement in general. hence my remarks.. i guess Manveet has put in exactly my thoughts in response.

dude plz beleive me , you wouldn't want to talk of upsizing your TB on a stock engine as the only mod ,the next question will always be what profle you running or are how much you boosted ? etc etc
I wouldnt want to comment on Manveets response right now