Tuner question

[illSHOyou]

Is there anyway to have the engine management disregard the MAF sensor after a set RPM and apply a forced fuel setting?

Something like after 4,800rpm? Is it even possible with the worst band aid manipulation you could think of? Maybe a do it once for a dyno pull, just guess what the theoretical air going into the engine might be?

YamahaSHO, possible?

 

[St Louis SHO]

Worst idea ever.

 

[kikkinasphalt]

Is there anyway to have the engine management disregard the MAF sensor after a set RPM and apply a forced fuel setting?

Something like after 4,800rpm? Is it even possible with the worst band aid manipulation you could think of? Maybe a do it once for a dyno pull, just guess what the theoretical air going into the engine might be?

YamahaSHO, possible?

yes you can. but why?

and i believe at WOT it is ignored anyway

 

[illSHOyou]

Worst idea ever.

O, you haven't heard the idea yet, trust me...

 

[somedude_001]

compressed shop air?

 

[rubydist]

People forget that too rich reduces power even more than too lean, it just isn't as fatal to the pistons......

 

[illSHOyou]

It just for testing purposes. I want to try a serious modification to the manifold, and for testing purposes wont be able to measure the air going in, but if you could sort of hack the computer we could probably guess and error on the rich side just to see if the mod shows something on the graph.

An additional air inlet into the plenum will only engage sometime after the secondary engagement. It would prove weather or not the stock intake is restricted because because lack of air in the plenum at maximum engine speed.

 

[illSHOyou]

compressed shop air?

You mean leaf blower and NOS? lol J/K

 

[NotSoSlowSHO]

and i believe at WOT it is ignored anyway

Bingo.

 

[illSHOyou]

Bingo.

Great news.

Thanks Guys.

 

[St Louis SHO]

O, you haven't heard the idea yet, trust me...

Hence the sarcasm, you've found your answer though.. :wave:

Oh, call me tomorrow evening, please.

 

[illSHOyou]

Hence the sarcasm, you've found your answer though.. :wave:

Oh, call me tomorrow evening, please.

Ok....

 

[sho_sc]

I must be missing something here .....

Yes, the MAF signal is used for WOT, the function curve is what determines the air flow.

and yes, you can "piggy back" a fuel multiplier on top of the MAF function curve based on RPM. But I would think you need some sort of MAF signal to be able to add fuel via the multiplier.

 

[yamahaSHO]

What Ransom said... The MAF is very much used in WOT. This is why the BT MAF guys can't hit the same AFR every run. The O2's are ignored while the MAF is being used.

You can add a fuel multiplier in relation to RPM, but this would be Vadim's way of tuning. You can add just about as much fuel as you want, however, it will be 'un-metered'.

Not sure why you would want to do this...

 

[Toolman]

What exactly would the comp be using to measure airflow @ WOT if the MAF were not used? Just curious what you guys were thinking.

If you are wanting the MAF ingnored in the sense of the comp thinking there is a certain amount of airflow (as compared to reality), then just change the curve to whatever kg/hr you like. DISCLAIMER: Toolman can not be held accountable for the disinegration of your engine because of a screwed up MAF curve!

As Jason said (do not think I am agreeing with you Jason, the planets may crash into each other if that happens!), SHOshop essentially ignored the MAF aboce 4800rpms, as with a high boost SC and BTM setup, the 80mm Linc were maxed well before redline, therefore the WOT vs RPM fuel multiplier was 'massaged'. (oh dang, maybe I did agree with you after all! 2012 here we come!!)

 

[SuperHO]

my only question is why are you so hellbent on proving the intake's a restriction?

 

[St Louis SHO]

my only question is why are you so hellbent on proving the intake's a restriction?

Who cares?

 

[illSHOyou]

What Ransom said... The MAF is very much used in WOT. This is why the BT MAF guys can't hit the same AFR every run. The O2's are ignored while the MAF is being used.

You can add a fuel multiplier in relation to RPM, but this would be Vadim's way of tuning. You can add just about as much fuel as you want, however, it will be 'un-metered'.

Not sure why you would want to do this...

This will be for testing purposes on a modified stock intake manifold. I am going to add one additional air inlet into each plenum with 2" control valves. This inlet will engage no sooner than stock secondary operation, but most likely later in the rpm band around 5,500rpm. This test will hopefully show a tq increase after engagement thus proving that the plenum are struggling to get enough air for the engine at max engine speed. The problem is the air will not be metered going into these two extra valves. At the point of engagement the stock MAF is going to see a drop in flow. This is why the computer system needs to be tricked. I believe sense its a N/A application we could guess pretty close to what the engine needs after this valve is opened. If the test proved successful then a proper way of measuring fuel can be added later. If the test goes south its not going to need future fuel management anyway.

Is the tweecer capable? or do I need a piggyback fuel controller?

 

[illSHOyou]

my only question is why are you so hellbent on proving the intake's a restriction?

I'm not, if anything prove that there was a 300hp prototype.

At max engine speed on the SHO I do believe there is high intake reversion most likely due to vacuum. The reversion would be indicated by a tq loss as less air is able to make it into the engine. If we could increase atmosphere pressure in the plenum it could lessen the affects of reversion and provide better cylinder filling.

With one additional inlet per plenum the plenum will get airflow equivalent to a 75mm TB. The mod, when activated, is like bolting a 75mm TB on each plenum. Then perhaps the SHO engine can make excellent tq throughout its whole speed range. (The inlet is 2" by the way)

With the stock intake once you get into the 4,800 rpm range the air is struggling to get into the plenum. The Y area is restrictive, and its not the most direct shot you can make for the air so you loss velocity. At 4,800 rpm everything is starting to approach max velocity anyway which means low pressure. Low pressure means reversion is not controlled as well. With additional inlets the plenum the air will slow down and drop velocity meanwhile create higher pressure at the runner inlet making the most of the runners. The runners will still be at high velocity regardless of the plenum. The stock snakes are going to only breath so far anyway, but there flow is hinder with the stock arrangement. Sure the stock runners wont resonant again but they will still flow alot of air.

These are some of the thoughts....

 

[SHOtime2511]

I'm not, if anything prove that there was a 300hp prototype.

who cares about HP? anyone can get the HP numbers,street cars need torque.