New intake system, Made by Mario at the dub shop Options

[edwin]

Ended up going Tps for the ecu anyway so I took it off again.

Going OT...what ecu are you using....I'm on SDS & could never get a good mps with the 2316 on itb's so have been on tps & it's fine. Uses closed loop for cruising, & seeks 14.1 afr nicely.

I agree with McMark about it being the ITB that are the problem not the ecu.
I use a Haltech Sprint 500 in the 914 and also my daily driven Saab. Great bang for buck?
I only ever did this as a temp solution.
The next phase is a bit more in depth but will take a little while.

[Darren C]

Interesting centre linkage you have there Edwin.

If the crank arms are at 45 degrees like standard twin carbs, you have your centre twin arm crank set up incorrectly.

(IMG:http://www.914world.com/bbs2/uploads_offsite/i265.photobucket.com-18255-1455027470.1.jpg)

I see this quite a lot, even with the dreadful cross bar linkages. Throttle cable movement when transmitted through a crank unless set right will give you an exponential throttle opening.

Hopefully my sketch shows what I mean. since the main crank point (where the throttle arms attach, scribe an arc; once they pass over the crest of any arc lateral movement is compromised by side movement, giving a disproportionate throttle opening in comparison to gas pedal depression).
Perfect proportional throttle is achieved if the centre main pivot has arms the same length as the carbs or throttle bodies; and the throttle cable bell crank arm length is calculated at a 90 degree rotational pull arc, based on linear cable pull.

[ChrisFoley]

...
Throttle cable movement when transmitted through a crank unless set right will give you an exponential throttle opening.
...

A cable wrapped around a pulley has linear throttle response. Just sayin' (IMG:style_emoticons/default/biggrin.gif)

[DBCooper]

Probably not, Chris, the coefficient of flow over a butterfly valve to its angle of opening isn't linear. Means it doesn't matter how you open the butterfly, throttle response isn't going to be linear.

[0396]

...
Throttle cable movement when transmitted through a crank unless set right will give you an exponential throttle opening.
...

A cable wrapped around a pulley has linear throttle response. Just sayin' (IMG:style_emoticons/default/biggrin.gif)

Chris,

Very logical, takes me back to my physics days.
You Da Man.

[Darren C]

...
Throttle cable movement when transmitted through a crank unless set right will give you an exponential throttle opening.
...

A cable wrapped around a pulley has linear throttle response. Just sayin' (IMG:style_emoticons/default/biggrin.gif)

I never mentioned a pulley, you're correct but in an unrelated way to the original meaning, as Cooper says and my observation of Edwin's photograph.

[rgolia]

How about one of these? A little pricey but do they work?

[rhodyguy]

A "little pricy"? (IMG:style_emoticons/default/sad.gif) dual paper filters and rain hats work great.

[Mark Henry]

How about:

Loose the ITBs, attach the intake directly to the manifolds, and source a single throttle body from a 3.2 (or similar).

Then, it's a mod with a purpose and there's no more linkage debate.

(IMG:style_emoticons/default/biggrin.gif)

I'd actually like to see something very similar, except with a single Ford mustang 70-75mm TB. Of course that would need a 2270cc
I just would like to know what the performance difference would be over ITB's. (IMG:style_emoticons/default/idea.gif)

The last time I did a comparative on a similar set up (with an even larger tubing ID) the engine lost 11HP and almost 20# of torque.

Air cleaner setup like posted or throttle body placement like Mark mentioned?

Almost exactly like this. The approach path of the air into the carbs favors one cylinder more than the other, among other issues.

Ended up going Tps for the ecu anyway so I took it off again.

Going OT...what ecu are you using....I'm on SDS & could never get a good mps with the 2316 on itb's so have been on tps & it's fine. Uses closed loop for cruising, & seeks 14.1 afr nicely.

That because of the ITB, not the ECU.

Basically that was my question in part because of MPS signal issues and the intake noise.
In my case at a ballpark 180hp, losing 10hp in a street car wouldn't be that big of a deal.

This is in my bug I will be also looking at my A1 exhaust to see if I can quiet it down a bit. I guess I'm getting old.

[Series9]

MAP sensor signal is a definite problem with ITBs. With a /6, you can smooth it out with a vacuum manifold that attaches to all six TBs. With a /4, you really can't. You have to perform "blending" in the programming of the ECU.

Doing a single TB and loosing the ITBs would likely solve that problem.

[r_towle]

How about one of these? A little pricey but do they work?

I happen to love that setup and will eventually suck it up and buy it.

In Germany there are very strict noise pollution laws.
Imagine living near the autobahn, and in many villages they are quite close to it.

Cars going over 100 MPH make quite a bit of noise, especially late at night when there is nothing else making noise...and a howling car goes by.

That system from CSP really does help reduce the noise, and I believe it uses a fairly easy to obtain paper air filter...

Rich

[Series9]

That's cool, but the MAP sensor problem will only be fully solved by putting the whole arrangement under vacuum, behind a single throttle body.

[sixnotfour]

Mario, of the dub shop (thedubshop.net) fabed up an awesome intake for the 914. It looks great and now I can even hear the Tangerine Racing exhaust over the itb's.

WOW, I have never seen a thread go more sideways, without anyone really looking at what he has..... (IMG:style_emoticons/default/bs.gif) what ever !!

[Mark Henry]

Mario, of the dub shop (thedubshop.net) fabed up an awesome intake for the 914. It looks great and now I can even hear the Tangerine Racing exhaust over the itb's.

WOW, I have never seen a thread go more sideways, without anyone really looking at what he has..... (IMG:style_emoticons/default/bs.gif) what ever !!

I might be the one to make it start going sideways, But I and many others in this thread know exactly what he has.

Megasquirt with crankfire ignition, CB Performance TB's and induction parts. Cool, but pretty standard fare now.

That said the OP was referring to the intake, right?

[Series9]

(IMG:style_emoticons/default/agree.gif)

The "sideways component" of this thread has been the linkage conversation. Everything else has been germane.

[sixnotfour]

I don't know either person on this post , maybe his terms were generic....what I take from this is he is happy with how it runs and is quiet (ITBs) to hear his exhaust, sounds to me like a happy guy...
He didn't ask for your approval...my bad...

[Bulldog9]

How about one of these? A little pricey but do they work?

Saving my pennies for someday.....

Back a few posts someone mentioned throwing away the CB arm linkage, and the resulting Q was asked "what do you suggest"

CFR has a throttle cable linkage that works great, is simple, easy to install, and looks great. HIGHLY recommend it..... Worth every $$.

[rgolia]

Does anyone know what unit from CSP is best for a 2 liter?

[trojanhorsepower]

Perfect thread for "how to learn never to post anything on 914World". (IMG:style_emoticons/default/biggrin.gif)

Amen brother! Nothing like a little common courtesy to make a person feel welcome. Oh wait, this is the opposite of that....

[wndsrfr]

How about:

Loose the ITBs, attach the intake directly to the manifolds, and source a single throttle body from a 3.2 (or similar).

Then, it's a mod with a purpose and there's no more linkage debate.

(IMG:style_emoticons/default/biggrin.gif)

(IMG:style_emoticons/default/agree.gif) Yep...that would give you a good mp signal, smooth throttle at normal cruising and have plenty of flow at w.o.t. and quiet it down nicely....