Problem adding fuel with Gems box

[Einar74]

Hi

A friend of mine has a Nytro with MPI stage 1 supercharger on it. He recently bought this sled in USA and shipped it to Iceland.

The sled is tuned for 7-9000ft on 8-9 psi. He wants to run this boost setting and is going to run AVgas in it at 0-4000 ft.

We went to today and tested the sled for the first time at maybe 1000ft.
Now for starters the sled run fine and never mist a beat during the short runs. But as expected the air-fuel radio was to high and it was reving to high.

Air/fuel was 14-14.5( prologger) and the rpm around 9100rpm. boost speaking 10+.

Now when we where going to add fuel with the Gems fuel box ( both have no prior experience with fuel boxes) it didn´t change anything adding fuel as the gems manual said. I started go into "red" mode and added fuel and even turned it all the way to "8" I didn´t see any difference on WOT. the "red" setting was on 4-5 when we started.

I then went to mode 4( fuel on boost) and set that to max and nothing change. Simply it didn´t matter what I played with the fuel "lights" or what mode, the sled run the same.

Could it be that the fuel pump and maybe injectors don´t support 8-10 psi at low elevation? but if so the air/fuel didn´t lean any more when I turned the "red" lights down again.

Regarding the clutching, can the adjustable screws be bought only, to add weight to the clutch or needs the weight to be replaced completely. to get the rpm down to 85-8800.
Do you know how much weight have to be added?

thank you
Einar

 

[Matt@MPI]

I think the fuel pump is to blame. At sea level fuel pump are done at 6-8 psi. Your fuel controller has enough fuel to supply that boost level. We have upgraded fuel pump kits in stock.

 

[Zipperno]

I think the fuel pump is to blame. At sea level fuel pump are done at 6-8 psi. Your fuel controller has enough fuel to supply that boost level. We have upgraded fuel pump kits in stock.

Hmmmm...the MCX 240hp kit runs the stock fuelpump at sealevel. They say the stock fuel pump is good for around 14 lbs.

Not saying you are wrong, could be a combo with stock injectors and bad pump that doesnt supply enough fuel.

 

[Matt@MPI]

Hmmmm...the MCX 240hp kit runs the stock fuelpump at sealevel. They say the stock fuel pump is good for around 14 lbs.

Not saying you are wrong, could be a combo with stock injectors and bad pump that doesnt supply enough fuel.

Your MCX kit runs a head shim right? With stock compression the fuel pump will not be enough.

 

[Einar74]

I think the fuel pump is to blame. At sea level fuel pump are done at 6-8 psi. Your fuel controller has enough fuel to supply that boost level. We have upgraded fuel pump kits in stock.

How much is your fuel pump kit? Do you have a link to the kit. I didn´t find it on your website.
Could I use a fuel pump from Apex?

Regarding the clutch setup I didn´t find the info you have previously told me about on your website.

thanks
Einar

 

[Matt@MPI]

Fuel pump upgrade $399.95. As far as the clutching goes its under SUPPORT on the web page. http://www.mountainperformance.com/Files/Download/msn-0900_supercharger_nytro_8-8-11-small.pdf

 

[Zipperno]

Your MCX kit runs a head shim right? With stock compression the fuel pump will not be enough.

Can you please elaborate on how a nytro fuel pump can support a 14lbs 240hp shimmed nytro and not a 10lbs stock cr nytro?

I have always thought a fuel pump can support a given number of hp.

I want to learn.

 

[A.Granath]

Can you please elaborate on how a nytro fuel pump can support a 14lbs 240hp shimmed nytro and not a 10lbs stock cr nytro?

I have always thought a fuel pump can support a given number of hp.

I want to learn.

First of all, mcx 240/270hp uses a extra set of injectors. Nytro 3 extra + 3 stock, apex 4 extra + 4 stock ect.

The stock injectors can only supply fuel for about 6-7psi of boost when using stock fuel pressure (~190hp).

If you upgrade to a better pump and fuel pressure regulator you can make the original injectors output some more fuel (10 psi boost or so, ~220hp).

If you are using a extra set of injectors (they don't need higher fuel pressure) the stock pump can deliver fuel for about 14psi (~240hp).

//AG

 

[Zipperno]

First of all, mcx 240/270hp uses a extra set of injectors. Nytro 3 extra + 3 stock, apex 4 extra + 4 stock ect.

The stock injectors can only supply fuel for about 6-7psi of boost when using stock fuel pressure (~190hp).

If you upgrade to a better pump and fuel pressure regulator you can make the original injectors output some more fuel (10 psi boost or so, ~220hp).

If you are using a extra set of injectors (they don't need higher fuel pressure) the stock pump can deliver fuel for about 14psi (~240hp).

//AG

Thanks!

The increased fuel pressure explains alot.

I know about the mcx stuff but isnt familier with the mpi sc. Thanks again.

 

[Einar74]

Fuel pump upgrade $399.95. As far as the clutching goes its under SUPPORT on the web page. http://www.mountainperformance.com/Files/Download/msn-0900_supercharger_nytro_8-8-11-small.pdf

Does the fuel pressure need to be raised?
I was thinking if I could install bigger injectors and achieve the same result. I saw on your website that your bigger injection kit for the Nytro is cheaper then the fuel pump kit.

in other post in this thread some are saying that the stock fuel pump supports 3 extra injectors in a MCX turbo application. I just found it a little strange that it flows enough for all that but it is out of steam with 3 stock injectors in this Supercharger setup.

But is the fuel pump upgrade better to keep smoother drivebility than going with bigger injectors using this fuel controller.

The main reason is I am in Iceland and was think I could get hold of stock Apex injectors( do they fit in the Nytro engine) sooner then getting the fuel pump from USA.

But maybe is doesn´t make no sense to add bigger injectors without bigger fuel pump.

thanks
Einar

 

[A.Granath]

Does the fuel pressure need to be raised?
I was thinking if I could install bigger injectors and achieve the same result. I saw on your website that your bigger injection kit for the Nytro is cheaper then the fuel pump kit.

in other post in this thread some are saying that the stock fuel pump supports 3 extra injectors in a MCX turbo application. I just found it a little strange that it flows enough for all that but it is out of steam with 3 stock injectors in this Supercharger setup.

But is the fuel pump upgrade better to keep smoother drivebility than going with bigger injectors using this fuel controller.

The main reason is I am in Iceland and was think I could get hold of stock Apex injectors( do they fit in the Nytro engine) sooner then getting the fuel pump from USA.

But maybe is doesn´t make no sense to add bigger injectors without bigger fuel pump.

thanks
Einar

If you feel that 10psi is enough for you i would go with the fuel pump upgrade, i don't think swapping injectors is a good solution (probably you need to flash your ecu to get them to work).

Also check your afr sensor so that it displays the correct value, after that take a look at your exhaust for leaks, that can also give wrong afr readings.

I personally would not go higher than 7-9psi on sea level even on avgas without retracted timing or a headshim I think you will be close to the line of meltdown and engine misery ... well just my opinion.

 

[Matt@MPI]

Does the fuel pressure need to be raised?
I was thinking if I could install bigger injectors and achieve the same result. I saw on your website that your bigger injection kit for the Nytro is cheaper then the fuel pump kit.

in other post in this thread some are saying that the stock fuel pump supports 3 extra injectors in a MCX turbo application. I just found it a little strange that it flows enough for all that but it is out of steam with 3 stock injectors in this Supercharger setup.

But is the fuel pump upgrade better to keep smoother drivebility than going with bigger injectors using this fuel controller.

The main reason is I am in Iceland and was think I could get hold of stock Apex injectors( do they fit in the Nytro engine) sooner then getting the fuel pump from USA.

But maybe is doesn´t make no sense to add bigger injectors without bigger fuel pump.

thanks
Einar

I think the fuel pump is the way to go. Drivability is a problem when adding larger injectors. We do offer a ECU reflash that will allow to run larger injectors.<O</O

 

[Einar74]

Thanks Matt for quick responds

I was thinking after seeing on your website that you are no fan of Avgas and I would need to run full race gas to be save with my setup at low elevation.

I started to think about your recommendation that you send me when I e-mailed you some time ago about changing the pulleys to 5-6psi setup. what would that pulley kit cost me? Can I run the same belt?

When I tested the sled and it was boosting to 10 psi even little bit more, I was thinking if I was simply overboosting the sled because it was running with to light clutch weight and there for over spinning the supercharger. the sled is setup for 8-9 psi at 7-9000ft

Regarding the clutch where do I get the rivets to add weight. are these Yamaha weights?

If you sell them, what would a set of rivets cost?

so I need a price for pulleys for 5-6psi and clutch rivets

thanks
Einar

 

[Matt@MPI]

Thanks Matt for quick responds

I was thinking after seeing on your website that you are no fan of Avgas and I would need to run full race gas to be save with my setup at low elevation.

I started to think about your recommendation that you send me when I e-mailed you some time ago about changing the pulleys to 5-6psi setup. what would that pulley kit cost me? Can I run the same belt?

When I tested the sled and it was boosting to 10 psi even little bit more, I was thinking if I was simply overboosting the sled because it was running with to light clutch weight and there for over spinning the supercharger. the sled is setup for 8-9 psi at 7-9000ft

Regarding the clutch where do I get the rivets to add weight. are these Yamaha weights?

If you sell them, what would a set of rivets cost?

so I need a price for pulleys for 5-6psi and clutch rivets

thanks
Einar

What pulleys do you have? Pulleys are about $100 each. We stock rivets and they don't cost very much.

 

[Einar74]

Fuel pump upgrade $399.95. As far as the clutching goes its under SUPPORT on the web page. http://www.mountainperformance.com/Files/Download/msn-0900_supercharger_nytro_8-8-11-small.pdf

Hi Matt

My friend(the owner) is still thinking about if he should go for the fuel pump upgrade or boosting down with different pulleys.

I talked about in former posts about running Avgas 100LL and you haven´t mentioned that that wouldn´t work running 8-9psi at low elevation. I saw on the technical support link from your MPI website that you don´t recommend Avgas, but you haven´t advice against it in previous posts and he wants to run as much power as he can get away with.

He will be buying stuff from you 100%, so what is the best way to make the order. just send you an e-mail?

I will must likely make the order and pay for it with Visa and have you send the stuff to my brother that lives in New Jersey.

Regarding the clutch rivets do you sell them in a set of 10 or something so we have a bag of different rivets to test ?

thanks
Einar

p.s. I guess the 10 psi we where seeing in the test where just because the motor was reving to 9100rpm and over spinning the supercharger. would you agree?

 

[Matt@MPI]

Hi Matt

My friend(the owner) is still thinking about if he should go for the fuel pump upgrade or boosting down with different pulleys.

I talked about in former posts about running Avgas 100LL and you haven´t mentioned that that wouldn´t work running 8-9psi at low elevation. I saw on the technical support link from your MPI website that you don´t recommend Avgas, but you haven´t advice against it in previous posts and he wants to run as much power as he can get away with.

He will be buying stuff from you 100%, so what is the best way to make the order. just send you an e-mail?

I will must likely make the order and pay for it with Visa and have you send the stuff to my brother that lives in New Jersey.

Regarding the clutch rivets do you sell them in a set of 10 or something so we have a bag of different rivets to test ?

thanks
Einar

p.s. I guess the 10 psi we where seeing in the test where just because the motor was reving to 9100rpm and over spinning the supercharger. would you agree?

We're not big fans of AV gas. I know lots of guys do it, so I'm not going to get into that. MPI's stance is to not run AV gas.

We sell rivets per each. So tell me what you want.

Email, phone, or PM all work to get a hold of me.