SUPERCHARGER

[assassin10000]

Originally Posted by Roman

Probably uses MAP as secondary feature, ie. to give it fuel cut at 12psi or something.

No fuel cut based on PSI/BAR afaik.

I believe it uses it to further 'fine' tune the fuel map based on psi/bar, beyond what it's already getting from readings @ the MAF. Probably helps if your end up with a boost leak as well. It may also do some correction when you lift off the pedal suddenly.

My friends s14sr is the only one I've actually seen with it (locally). And his sr20 runs way stronger than many of the others I've been in. It takes other guys lots of mods to keep up with him. He only has a downpipe, intercooler and 3" exh, and running on 7psi. Most people who swap them here don't get the boost pressure sensor as nissan put them inside the engine bay fuse box of all places, or they just don't realize it's in there if they were fortunate enough to get it with their swap. And most people are running 10psi boost on their motors, nissan put a special restrictor in one of the vacuum lines for the wastegate that limits boost to 7psi. Most people replace all the vacuum lines and don't realize that it's in there. And without it there is a sudden jump to 10psi.

Andrew

[MANDALAY]

Cant help thinking that maybe Toyota was going to make a v2 of the beams because of the nipple in the inlet manifold ?
OK
now , belt tensioners.
I have been put on to a company called GATES .
Dam there are soooooooo many tensioners.
There are 2 ive got my eye one.
One has a plastic wheel the other a metal one. Which one should l go for ? Also imagine
Crankshaft pulley and SC pulley and the belt. Looking at the pulleys the SC is on the left and the belt is rotating clockwise. Should the tensioner be put b/w the belt moving from the Crankshaft to the SC or the SC to the crankshaft ?
Also have been told the STD MAF is ok for 8 PSI. 260 whp

[Servin]

A little late to the pas couple of post but hopefully this will help out some

A MAP, MAF and AFM are all used to measure the amount of air in the engine. However they do it by different methods.

A MAP (Manifold Absolute Pressure) sensor measures the vacuum or boost, in a turbo or supercharged application. The amount of air is then calculated using the volumetric efficiency of the engine and temperature of the air. In reality it is a referred to a table in the ECU program. The MAP sensor allows you to calculate the mass of air and from that you can determine the mass of fuel you need to inject. Older fuel injected cars tend to use MAP.

A MAF (Mass Air Flow) or AFM (Air Flow Meter) measure the mass or volume of air. These work in various ways including measuring the cooling effect of the air as it passes a heated element, vortex shedding. Older methods include a vane which is pushed by the air flow. There is usually some compensation for temperature. As you basically measuring the mass of air it is more direct measurement and you can easily calculate the mass of fuel required. Most if not all new cars run MAF/AFM.

Can you swap them?
Not with your standard ECU. Aftermarket ECUs may be able to use either.

Which is better?
Most high horsepower guys seem to like MAP as it eliminates a restriction in the intake path. You can also exceed the range of a MAF/AFM in big horsepower application both at the top end or at idle. From an engineer's point of view I think that the MAF/AFM is a more precise method. From an emissions and efficiency point of view a MAF/AFM is normally the better approach.

MAF/AFM Tubes
Some people sell larger diameter intakes which you transfer your MAF/AFM to. The change in tube diameter actually changes the calibration of the MAF/AFM. Basically it can make you car run leaner which under full throttle applications may improve horsepower at the risk of engine damage.

MAP to MAF Converters
These are also available which allow you to run a MAP sensor in place of your MAF/AFM sensor.


Really for what you are looking at I would stick with the MAF/AFM. Also if needed to go higher HP I know nissan folks who use a MAF use a Ford Cobra MAF for power up to the 600WHP range. So using a MAF/AFM isnt too limiting its only when you want really big numbers that you might want to convert to MAP.

[Servin]

Also put the tensioner in the direction the belt is moving so from the SC to the crank pulley. Putting it in the opposite direction would cause friction not something you want on a belt. Get metal it will keep its shape better, wont break if you over tq a bolt, etc. Also will the tensioner support the rpms the belt will be turning?

[assassin10000]

Originally Posted by MANDALAY

One has a plastic wheel the other a metal one. Which one should l go for ?

Also imagine Crankshaft pulley and SC pulley and the belt. Looking at the pulleys the SC is on the left and the belt is rotating clockwise. Should the tensioner be put b/w the belt moving from the Crankshaft to the SC or the SC to the crankshaft ?

Also have been told the STD MAF is ok for 8 PSI. 260 whp

Metal. Heavier, but less likely to break &/or have problems.

When you say left, you mean looking at the front of the motor he S/C will be on the left side (timing cover/waterpump/ect). Which is actually the 'right' side of the motor? You should mount the tensioner 'behind' the S/C pulley.

So following rotation of the belt: Crankshaft -> S/C pulley -> Tensioner.
Given your description it would go on the 'bottom' side, you could put the adjuster facing downwards so when you tighten it it pulls the pulley down, and the adjusting nut will be accessible from the bottom of the car/engine bay.

Stick with MAF if it's proven to be fine. Once it's in for tuning is when you'll be able to tell if the MAF voltage platues and the MAF is too small. I'm not too sure on who you talked to, since some of those guys could be running the MAF after the s/c which will give different readings...

Andrew

[MANDALAY]

Sorry for the confusion
Looking at the belts

_____>______
SC______<_____ CRANK < is the rotation clockwise

so the tensioner goes ? B/W crank to SC

OR SC to crank.

[puretone]

the fusebox of all places! car manufacturers do the darndest things i swear!

[MANDALAY]

^ ?

[assassin10000]

He's talking about my post at the top of this page - s14sr boost pressure sensor being tucked away in the fuse box.


S/C-->---->--Crank
..---<-Tens-<---

That way the inital pull/torque is applied to the S/C.

Andrew

[MANDALAY]

Got you on both counts Thanks buddy

[MANDALAY]

Oh before i buy the SC really need to know the pully diameter on the crankshaft. The one that drives the alternator. Anyone ?

[Servin]

So you need the diamter for the crank pulley? I can get that for you no problem.

[MANDALAY]

^ cool .

[2muchfun]

16 3/4 inches. I measured with a tape measure as I didn't have a spare belt to cut up. I hope that helps.

Brad.

[MANDALAY]

Hi Brad , thanks but i need the diameter of the crankshaft pulley that drives the alternator

[Roman]

Originally Posted by assassin10000

Stick with MAF if it's proven to be fine.

Nah, the MAF has proven to be a big pain in the ass most of the time!

For a road going NA setup, I think that MAF is the way to go.

However for FI I'd go for MAP, simply because it's measuring point is inside the manifold, close to the 'action'.

It doesnt matter if you've got an air bleed valve for when the throttle is shut, or lots of piping in between air filter > supercharger > intercooler etc, or turbulence in the intake, or whatever.... gives a good signal regardless, is harder to 'upset' unless you've got quad throttles with small amount of volume behind throttles.

If you've got an airbypass for when the throttle is shut, is this going to be air that has been 'read' by the MAF?

[2muchfun]

If you need the diameter for the MR2 crank shaft pully, that is what I measured on mine.

[MANDALAY]

Originally Posted by Roman

Nah, the MAF has proven to be a big pain in the ass most of the time!

For a road going NA setup, I think that MAF is the way to go.

However for FI I'd go for MAP, simply because it's measuring point is inside the manifold, close to the 'action'.

It doesnt matter if you've got an air bleed valve for when the throttle is shut, or lots of piping in between air filter > supercharger > intercooler etc, or turbulence in the intake, or whatever.... gives a good signal regardless, is harder to 'upset' unless you've got quad throttles with small amount of volume behind throttles.

If you've got an airbypass for when the throttle is shut, is this going to be air that has been 'read' by the MAF?

This last sentance is whats confusing me of late . Not sure which way it is but can you clarify it, If it was MAP the ampount of fuel metered will be based on a lot of things but two are air pressure and temp. Lets say it is pumping 10 mls with the throttle open then all of a sudden the throttle is closed wont there be too much fuel and it will rich out ?
Or is that what happens in the same scheme
with a MAF ?
Are the HKS BYPASS valves any good as the say the Bosch ones break down on their rubber seal.
Also you loose the knock sensor on a MAP . i SEE this as a bad thing but again have been told that its the tuner to make sure its tuned properly so it doesnt happen.
Lastely with MAP do you still have cold start function you know how it revs slightly more until its warm.

[MANDALAY]

Originally Posted by 2muchfun

If you need the diameter for the MR2 crank shaft pully, that is what I measured on mine.

Hi Brad l mean not the belt the actual pulley itself

[puretone]

Originally Posted by MANDALAY

Are the HKS BYPASS valves any good as the say the Bosch ones break down on their rubber seal.

Chicks will think you are super hot if you have an HKS BOV man!!1!