The Technical Questions Thread

[NSXType-R]

Originally Posted by Kitdy

Hijack time.

Why does this engine have the 6 exhausts or whatever the chrome things are in a row when it is a V6? Wouldn't it be more normal to have three on each side? Am I crazy? Is this peculiar in any way? Help!

Not a problem. In fact, I have a question myself.

What are individual throttle bodies?

How does it help the engine produce more power?

Can someone attach a photo too to help me out?

Thanks.

[clutch-monkey]

Originally Posted by Jack_Bauer

The chromed pipes are the induction pipes, not the exhaust. You can just about see the exhausts on the nearside bank of cylinders, the red curved pipes below the cylinder head cover, and it will indeed have three exhausts on each side.

question - how woud the exhausts cope with a similar chrome finish - would the chrome simply degrade due to heat?

Originally Posted by NSXType-R

Not a problem. In fact, I have a question myself.

What are individual throttle bodies?

How does it help the engine produce more power?

Can someone attach a photo too to help me out?

Thanks.

ooh that's a good one. would also like to know

[NSXType-R]

Originally Posted by clutch-monkey

question - how woud the exhausts cope with a similar chrome finish - would the chrome simply degrade due to heat?

ooh that's a good one. would also like to know

Chrome is pretty weather resistant right? It shouldn't degrade much due to heat then. Sometimes there are a lot of chrome parts under the hood, so it shouldn't degrade much. Chromed parts are electromagnetically plated right? It should stick very well. I could be wrong though.

[clutch-monkey]

Originally Posted by NSXType-R

Chrome is pretty weather resistant right? It shouldn't degrade much due to heat then. Sometimes there are a lot of chrome parts under the hood, so it shouldn't degrade much. Chromed parts are electromagnetically plated right? It should stick very well. I could be wrong though.

i think you're right, i might be confused with something else - just remembered they make chrome lined rifle barrels, so it must be durable.

[jediali]

Originally Posted by NSXType-R

What are individual throttle bodies?

this is a bmw i6:

you can sea an individual throttle body for each cylinder. This ensures equal intake conditions to each cylinder allowing higher combustion performance paramaters. This is better than a single throttle butterfly valve leading to multiple cylinders as in:
http://www.itrsport.com/images/tech_...rotle_body.jpg
or
http://www.supercar-engineering.com/...rottleBody.jpg

If one can be sure that each cylinder is getting an equal amount of air and the air itself is behaving similarly (swirl characteristics, spark centre, hotspot etc) in all 6 cylinders the compression ratio can be a little higher and the valve timing can be a little more precise (in intake/exhaust gas overlap and inertia filling) thus improving thermal efficiency and burning more fuel more effectively. Therefore more powAr

[clutch-monkey]

what kind of gains can be expected with itb's? i mean are we talking the cold air intake kind of gains of a few hp, or a significant gain?

[nota]

Originally Posted by clutch-monkey

i think you're right, i might be confused with something else - just remembered they make chrome lined rifle barrels, so it must be durable.

I wouldn't imagine intakes getting hot enough to discolour, unlike chrome motorcycle exhaust pipes eg

A mate not just overheated but cooked the iron block of a brand-new Army Ford Flathead V8 so bad that the block turned permanently blue

Originally Posted by NSXType-R

What are individual throttle bodies?

Can someone attach a photo too to help me out?

Jedali has it covered but for the hell of it here's two pics of that gorgeous Harrop Hurricane 8 Butterfly intake for Chev LS1 V8s

[jediali]

Very nice Nota, fantastic example of the enginuity that goes into itb's. Are they fuel rails to the sides?

[LotusLocost]

Originally Posted by drakkie

I'd say it has two exhaust valves per cilindre and therefor one pipe for each valve...

Good answer Sherlock. I can't wait to drive the cars that you are going to design in the future.

Originally Posted by clutch-monkey

what kind of gains can be expected with itb's? i mean are we talking the cold air intake kind of gains of a few hp, or a significant gain?

You are talking massive gains yes. ITB's can on a 4 pot 2l produce 40 - 60 hp more, easily. But you have to upgrade the ignition most certainly and also alot of "mapping" and dyno runs has to be done to get good results. (computer setup for the ignition) You can also have much larger gains if more work is put into an engine.. One example: Opel/Vauxhal 2.0 EX, standard output with fuel injection: 156 hp. Race prepped 2.0 EX with ITB's 270-290 hp.

You can compare it with a single-weber conversion/upgrade on your single SU carburetted mini engines. Or a conversion from single carb on a crossflow type head, to a double weber set-up.

Originally Posted by jediali

Very nice Nota, fantastic example of the enginuity that goes into itb's. Are they fuel rails to the sides?

That is fuel lines yes.
And I must also say that those look very good!

[clutch-monkey]

Originally Posted by LotusLocost

You are talking massive gains yes. ITB's can on a 4 pot 2l produce 40 - 60 hp more, easily. But you have to upgrade the ignition most certainly and also alot of "mapping" and dyno runs has to be done to get good results. (computer setup for the ignition) You can also have much larger gains if more work is put into a engine.. One example: Opel/Vauxhal 2.0 EX, standard output with fuel injection: 156 hp. Race prepped 2.0 EX with ITB's 270-290 hp.

so, the gains are very good, but because it seems to be very finely tuned, does that mean you have to be careful with the quality of fuel etc? i.e., is there less room for error

[culver]

Originally Posted by Jack_Bauer

Variable length intake manifolds.

There is a long and a short pipe for each individual cylinder, and the intake switches between the two depending on revs - long pipe for low revs and short pipe for higher revs (I think!).

Just about! You are correct at low revs. At high revs it uses both sets of pipes. More importantly it looks really cool!

[jediali]

Originally Posted by LotusLocost

Good answer Sherlock. I can't wait to drive the cars that you are going to design in the future.

What does he study again

Originally Posted by LotusLocost

You are talking massive gains yes. ITB's can on a 4 pot 2l produce 40 - 60 hp more, easily. But you have to upgrade the ignition most certainly and also alot of "mapping" and dyno runs has to be done to get good results. (computer setup for the ignition) You can also have much larger gains if more work is put into an engine.. One example: Opel/Vauxhal 2.0 EX, standard output with fuel injection: 156 hp. Race prepped 2.0 EX with ITB's 270-290

that much! I assume its a total engine concept where gas flow is thoroughly engineered.

[LotusLocost]

Originally Posted by jediali

that much! I assume its a total engine concept where gas flow is thoroughly engineered.

Not necessarily. Take the example I mentioned earlier, Opel/Vauxhal 2.0L EX.
Standard output with single plenum chamber fuel injection: (stated from factory, could be less) 156 hp.
Convert it to 45 mm Dellorto Carbs and you are up to 175 - 180 hp (gain 19 - 24hp)
Convert it to ITB's and I think you can gain up to 40 hp and more without doing anything to the engine, but changing the ignition and the ITB's of course.

The given example with carbs is dynoed hp in my brothers seven, who had that exact setup. Standard Calibra 2.0 EX engine with 45 mm dellorto carburetors . It should be mentioned that we have to have 38 mm restrictors in the carbs so with 40/42/none mm restrictors it would have been more gains of course.

And for the 270 - 290 hp you are talking very raced prepped yeah.. I have a friend who has a Kadette with the 2.0 EX with ITB's and rear-wheel drive conversion. I think he has dynoed 280 or something this spring.

[henk4]

slightly off topic, but still related

can anybody explain why a flat-head V8 as shown here would have three carbs and also only 3 exhausts per bank?
This particular Special was shown at Laguna Seca in 2005, but I have seen several other engines with the same set-up. Nobody was actually to give me an explanation (that I understood )

[jediali]

Originally Posted by henk4

slightly off topic, but still related

can anybody explain why a flat-head V8 as shown here would have three carbs and also only 3 exhausts per bank?
This particular Special was shown at Laguna Seca in 2005, but I have seen several other engines with the same set-up. Nobody was actually to give me an explanation (that I understood )

excuse my rough image, this explains three outlets, i can only assume the 3 carbs feed into a common manifold that splits to the 8 inlets. each circle represents a intake (blue) or exhaust(red) valve. The two central exhausts must meet in the cylinder head itself. This V8 was noted as cost effective so this would make sense. For those who don't know what flathead means:
http://www.dkfritidbil.dk/motor/valve.6.jpg