Boring out k11 throttle body?
- Thread starter jamieccc
- Start date
squarepants
Ex. Club Member
ga16 throttle body? ga16 or sr20 injectors and a re-map 
Alienfish360
Awesome Dawson
No need unless you're running in excess of 150bhp.
ollie240585
Ex. Club Member
GA16 does fit straight on, but it is pointless unless like phil says, you're running in excess of 150 BHP
frank
Club Member
jamieccc
i can,t see why a 1.3 wont benefit from a bigger t/b (especially at high revs), if you go for primera injectors the engine needs to gulp more air to go with the extra fuel (meaning less need for a remap)
there are 2 valves at the front of the ga t/b that you need to remove, and the cable mount fouls the number#3 injector
i can,t see why a 1.3 wont benefit from a bigger t/b (especially at high revs), if you go for primera injectors the engine needs to gulp more air to go with the extra fuel (meaning less need for a remap)
there are 2 valves at the front of the ga t/b that you need to remove, and the cable mount fouls the number#3 injector
frank
Club Member
jamieccc
i can,t see why a 1.3 wont benefit from a bigger t/b (especially at high revs), if you go for primera injectors the engine needs to gulp more air to go with the extra fuel (meaning less need for a remap)
there are 2 valves at the front of the ga t/b that you need to remove, and the cable mount fouls the number#3 injector
edit why did that doublepost ?? i only clicked once :devil:
i can,t see why a 1.3 wont benefit from a bigger t/b (especially at high revs), if you go for primera injectors the engine needs to gulp more air to go with the extra fuel (meaning less need for a remap)
there are 2 valves at the front of the ga t/b that you need to remove, and the cable mount fouls the number#3 injector
edit why did that doublepost ?? i only clicked once :devil:
Alienfish360
Awesome Dawson
The thing is, it won't benefit, as there are far more restrictive parts, such as the design and shape of plenum chamber and the inlet manifold, the head etc.
A bigger throttle body will still be restricted by the above factors.
Unless running big power, the CG throttle body is not restrictive.
A bigger throttle body will still be restricted by the above factors.
Unless running big power, the CG throttle body is not restrictive.
frank
Club Member
alienfish360
i can,t see your logic ? is the same t/b as fitted to the 1.0, too big for a 1.0 then ?
if i fitted a 20mm bore t/b, would i have the same power as with a 60mm bore t/b ??
in karting the only difference between the junior (slower) karts, to the senior (quicker) karts is a smaller choketube in the carburettor, but the engines are identical !
i can,t see your logic ? is the same t/b as fitted to the 1.0, too big for a 1.0 then ?
if i fitted a 20mm bore t/b, would i have the same power as with a 60mm bore t/b ??
in karting the only difference between the junior (slower) karts, to the senior (quicker) karts is a smaller choketube in the carburettor, but the engines are identical !
Alienfish360
Awesome Dawson
that was the way those engines were made to be restricted in terms of power.
Do you think that the millions of ££££ spent on designing and building the CG10 and 13 engines that Nissan spent, if the TB wasn't suitable, they'd have stuck it on anyway?
The point is, there are much much more restrictive parts of the engine than the TB. The TB poses no restriction, and CAN and DOES provide enough Air to run up to around 150bhp.
It's like a funnel, it doesn't matter how massive the big end is, you can only get the small bit out.
And in the CG engines, the "small end" of the funnel is the head, and inlet manifold design. Sort them out before you even look at a throttle body.
There are plenty of other issues that you have with the GA16 having idle issues with the parts disconnected required to make it fit.
Unless you're needing the air to mix with the fuel needed at over 150bhp the standard throttle body is adequate, and if you need more air, get an inlet manifold custom made to fit the GA16 or SR20 tb's properly.
Do you think that the millions of ££££ spent on designing and building the CG10 and 13 engines that Nissan spent, if the TB wasn't suitable, they'd have stuck it on anyway?
The point is, there are much much more restrictive parts of the engine than the TB. The TB poses no restriction, and CAN and DOES provide enough Air to run up to around 150bhp.
It's like a funnel, it doesn't matter how massive the big end is, you can only get the small bit out.
And in the CG engines, the "small end" of the funnel is the head, and inlet manifold design. Sort them out before you even look at a throttle body.
There are plenty of other issues that you have with the GA16 having idle issues with the parts disconnected required to make it fit.
Unless you're needing the air to mix with the fuel needed at over 150bhp the standard throttle body is adequate, and if you need more air, get an inlet manifold custom made to fit the GA16 or SR20 tb's properly.
frank
Club Member
alienfish360
the 4 inlet tracts (head or manifold) have a combined surface area of about 2464sq mm, how can the stock t/b, with a surface area of only about 1590sq mm (minus an obstructive butterfly spindle) "not" be obstrutive ??
and why did nissan fit the same size t/b to the 1.0 and 1.3 ? (they cant both be ideally suited !!)
the 4 inlet tracts (head or manifold) have a combined surface area of about 2464sq mm, how can the stock t/b, with a surface area of only about 1590sq mm (minus an obstructive butterfly spindle) "not" be obstrutive ??
and why did nissan fit the same size t/b to the 1.0 and 1.3 ? (they cant both be ideally suited !!)
Alienfish360
Awesome Dawson
surface area isn't everthing, look at flow rates too. What's the point in having it, if the head and inlet manifold can't flow that much.
It's difficult to install Nitrous Oxide on a K11 without using direct port injection due to the poor design (in terms of performance) of the inlet manifold and plenum chamber, they don't flow evenly, and is very restrictive.
It goes to show how badly designed the inlet manifold is.
In regards to them both being ideally suited, the throttle body is big enough for the CG13, and big enough for the CG10, if people are able to run 150bhp on turbo'd K11's with a stock TB, there's no reason to change one running a janspeed or anything that's not got serious power.
Remember, the CG10 and CG13 share a LOT of parts, and you can be positive that they will be more than suitable for the engine, or else they wouldn't have spent the money in R&D.
You will not gain power from changing the throttle body without first changing the inlet manifold, the head isn't exceptionally poor, but the inlet manifold and exhaust manifolds are the most restrictive parts of the CG series engine.
Get a dyno read out, and then put a GA16 throttle body on it, and get another dyno read out. I will happily put £20 down that you will get no power increase, chances are you'll drop a couple.
It's difficult to install Nitrous Oxide on a K11 without using direct port injection due to the poor design (in terms of performance) of the inlet manifold and plenum chamber, they don't flow evenly, and is very restrictive.
It goes to show how badly designed the inlet manifold is.
In regards to them both being ideally suited, the throttle body is big enough for the CG13, and big enough for the CG10, if people are able to run 150bhp on turbo'd K11's with a stock TB, there's no reason to change one running a janspeed or anything that's not got serious power.
Remember, the CG10 and CG13 share a LOT of parts, and you can be positive that they will be more than suitable for the engine, or else they wouldn't have spent the money in R&D.
You will not gain power from changing the throttle body without first changing the inlet manifold, the head isn't exceptionally poor, but the inlet manifold and exhaust manifolds are the most restrictive parts of the CG series engine.
Get a dyno read out, and then put a GA16 throttle body on it, and get another dyno read out. I will happily put £20 down that you will get no power increase, chances are you'll drop a couple.
Paul Smith
Site Supporter
I think, if you fit the 1.6 injectors then your right more fuel should be forced through them, but it isn't the standard ecu corrects the amount of fuel so no gains there, and the 1.6 throttle is hard to setup on the standard cg ecu (because of the mods to it ). surely the ga15 throttlebody (if you can find one) has to be a better idea as there is no modding but like the ga16 you gain the extra 5mm throttle chamber. However all this is still corrected by the ecu so with out a remap there will be real minimal if any gains.
I can see both your points good thread
I can see both your points good thread
Alienfish360
Awesome Dawson
I will happily be corrected on this by an ECU expert, eg. Pete, Ed etc.
However, regardless of what size injectors are in, the stock ecu, will still think that the injectors are the standard size.
Therefore, will hold the injectors open for the same amount of time, causing over-fuelling, the only way for the ecu to correct is by the feedback from the lambda. However, as it still doesn't know the size of the injectors, it still cannot correct it accurately.
However, regardless of what size injectors are in, the stock ecu, will still think that the injectors are the standard size.
Therefore, will hold the injectors open for the same amount of time, causing over-fuelling, the only way for the ecu to correct is by the feedback from the lambda. However, as it still doesn't know the size of the injectors, it still cannot correct it accurately.
frank
Club Member
alienfish360
i would gladly lay £20 that a ga1.6 t/b with primera injectors will show a gain (especially at high revs), thats exactly what is fitted to my car
my lambda readings are ok in all conditions, so no need for a remap (tho i daresay the settings could be optimised)
paul
i think the ecu will only correct the a/f ratio when in closed loop, not at wide open throttle tho, when its in open loop (which is exactly when you need more fuel and more air
i would gladly lay £20 that a ga1.6 t/b with primera injectors will show a gain (especially at high revs), thats exactly what is fitted to my car
my lambda readings are ok in all conditions, so no need for a remap (tho i daresay the settings could be optimised)
paul
i think the ecu will only correct the a/f ratio when in closed loop, not at wide open throttle tho, when its in open loop (which is exactly when you need more fuel and more air
I dont have time to write a long reply - sorry. But the most I know of anyone making on a 1.6 TB is 130bhp and that was on a SUN dyno, which usually reads more than dyno dynamics. I wouldnt waste my time doing anything to a K11 intake manifold. To much effort for too little gain.
