"Dude I bolted on 25 BHP" FAQ !!

[v1p3r]

With a TB spacer, you will get some swirl into your charge mixture IF the spacer is placed AFTER the fuel and air is mixed. So the thing is slightly effective for TBI and carbed cars. For an MPFI car, it just pushes the airfilter an inch or so further away from the intake valves.

[The Wolf]

V1p3r, there are throttly body spacers that dont have the grooves at all! The grooves thingie is just a value add to the product... The main idea of a tb spacer is to increase the cc of plenum chamber...bigger the plenum chamber, lesser the charge required to suck maximum air in due to pre available air in the chamber...resulting in what?? well, more torque at higher rpms but marginal drop at low rpm!

The one which has grooves as you mentioned would function best if placed after the runners/carb as it slows down the velocity of air giving the fuel more time to mix(atomize) before entering the combustion chamber...

p.s: OE plenum chamber is designed(cc calculation) to support maximum air flow throughout the rpm band. Custom ones enhance one range on the rpm band at the cost of another one.

[chetanhanda]

Originally Posted by The Wolf

V1p3r, there are throttly body spacers that dont have the grooves at all! The grooves thingie is just a value add to the product... The main idea of a tb spacer is to increase the cc of plenum chamber...bigger the plenum chamber, lesser the charge required to suck maximum air in due to pre available air in the chamber...resulting in what?? well, more torque at higher rpms but marginal drop at low rpm!

exactly and some of these are so thin that they would hardly increase the cc at all...or even create a swirl effect

Originally Posted by The Wolf

The one which has grooves as you mentioned would function best if placed after the runners/carb as it slows down the velocity of air giving the fuel more time to mix(atomize) before entering the combustion chamber...

yes, exactly and again it would be doubtful if these spacers are going to help as the intake runner length of a stock engine would be optimised for that engine for that particular intake valve timing for that cam..

Originally Posted by The Wolf

p.s: OE plenum chamber is designed(cc calculation) to support maximum air flow throughout the rpm band. Custom ones enhance one range on the rpm band at the cost of another one.

yes , and possibly these spacers being of the generic type may even not be suited to the type of cams or header design the engine is being tuned with, they could be in some cases going against the other mods done..

[chetanhanda]

Originally Posted by v1p3r

With a TB spacer, you will get some swirl into your charge mixture IF the spacer is placed AFTER the fuel and air is mixed. So the thing is slightly effective for TBI and carbed cars. For an MPFI car, it just pushes the airfilter an inch or so further away from the intake valves.

yep..right.. somewhere downstream in the runner after the injector... but who knows ..there may be better ways to acheive the same.. like playing with injector spray pattern, runner design which may have already been taken care of by the manufcturer or the aftermarket intake plenum designer..

e.g. a aftermarket Skunk intake on a Honda may have been already so well designed that a spacer in the runner would be most unecessary...

I would call TB spacers as the most useless concept in a MPFI system upsteram or downstream of the injector in the runner...

[chetanhanda]

Originally Posted by ported_head

Does the output voltage of the IAT sensor rise as temperature goes up?

the lower the temperature, the higher the resistance.so higher the resistance lower the voltage ..I think its what u call a "thermistor"

[ananthkamath]

Originally Posted by chetanhanda

I would call TB spacers as the most useless concept in a MPFI system upsteram or downstream of the injector in the runner...

I think they're pretty handy if you want to inject nitrous into the engine.

[chetanhanda]

Originally Posted by chetanhanda

I would call TB spacers as the most useless concept in a MPFI system upstream or downstream of the injector in the runner...

Originally Posted by ananthkamath

I think they're pretty handy if you want to inject nitrous into the engine.

then even sparkplugs, plug wires are very handy if you are using NOS becoz an engine capable of using NOS will definately benefit from these..
so whatever we have discussed in the last few post makes no sense.
so that means plug wires and sparkplugs are pretty usefull to mantain a 100 shot of NOS ..
dont you think this is in wrong context ?

[chetanhanda]

Originally Posted by ananthkamath

I think they're pretty handy if you want to inject nitrous into the engine.

again they maybe handy only in case of "wet" or "direct port" type of Nitrous delivery but not in a "Dry" system as we are spraying NOS upstream of the injector on/near the MAP...
a dry delivery system has to be upstream of injector to influence te MAP sensor so it wont be useful here..

[ananthkamath]

i meant to say that a TB spacer will be useful not as a power adder, but as a means of actually fitting the nitrous line to the engine. meaning you drill a hole in the periphery of the TB spacer and attach the nitrous line there, much like a plate system. this was an oblique reference made to nitrous in a sarcastic manner, thats it.

dry, wet it doesnt matter. you still need to inject the nitrous somewhere, and the neatest way to do it is through a plate (or like i meant, a tb spacer) fitted to the plenum. an inelegant way is to pierce the rubber tube from the airbox.

[chetanhanda]

Originally Posted by ananthkamath

this was an oblique reference made to nitrous in a sarcastic manner, thats it.

got it late.. I have some turbo lag...

Originally Posted by ananthkamath

dry, wet it doesnt matter. you still need to inject the nitrous somewhere, and the neatest way to do it is through a plate (or like i meant, a tb spacer) fitted to the throttle body. an inelegant way is to pierce the rubber tube from the airbox.

direct port into intake after TB , wet shot sprayed ahead of TB..

[WhiteKnight]

Originally Posted by chetanhanda

the lower the temperature, the higher the resistance.so higher the resistance lower the voltage ..I think its what u call a "thermistor"

Well, depends on the coefficient of resistance being +ve or -ve. I presume you are refering to a -ve thermister?

[v1p3r]

Best way of spraying nitrous is to not, and use a turbo instead.

[rdkarthik]

Originally Posted by ported_head

Does the output voltage of the IAT sensor rise as temperature goes up?

Hotter the stuff, lower is the resistance...... If you want to play with IATs, do it with the resistance, dont worry abt voltages.

[gigy]

what are all of you trying to do with changing resistance of sensors? when the air temperature is high it is the sensor responsibility to inform the ECU and it adjust the fuel accordingly.
so if you force ECU to think the engine is being fed cold air, are you expecting increase in power. Tecnically it is not possible. only when the correct input data is given the ECU, it can produces power as per throttle position.
if you need more power increase mass air flow( turbo), try for colder air (CAI) intake and fuel , allow faster exhaust exit within the power band possible from engine. rest all theory is pure ****.
there is one basic rule for everything, energy can neither be created nor destroyed. so there has to be more input for more output...... how much you can drag this is based on limits of the engine physical size and related things.

[ananthkamath]

Originally Posted by v1p3r

Best way of spraying nitrous is to not, and use a turbo instead.

or both if you are psychotic enough.


this thing of using a resistor. in parallel with the sensor. I am assuming it has been tried and is a cheap remedy to get rid of a lean condition? Someone please comment on this.

how about discussing a "sequence" of mods one can follow if one has a stock engine and would, theoretically atleast, provide the best bang-for-the-buck?

my take on this is:

Stage 1) Open filter/CAI etc. with rejetting for carburetted engines and no changes for FI engines
Stage 2) Full exhaust system from cylinder head flange onwards (not just freeflowing muffler) along with rejetting/remapping/piggyback
Stage 3) Synthetic oil if it isnt already recommended by manufacturer
Stage 4) Internal modifications like cams, head work etc.

This is for a street engine. If I were to be building a race engine, I would take a "systems approach", meaning that I would start with internal mods first (cams, head work, CR) then match the exhaust and intake system with those components.