Jimny Supercharged

[Spike_Sierra]

How about a rising rate fuel pressure regulator?

Ben

I just tried restricting the fuel flow through the return line with vice grips to see if it changed the air/fuel ratio, it appears it didnt. I didnt have that much time to check everything, but is there any explaination to this. Could i have just not been clamping tight enough. I only let it idle, so i dont know how it would be on the road or under boost.

[lay80n]

How about a rising rate fuel pressure regulator?

Ben

I just tried restricting the fuel flow through the return line with vice grips to see if it changed the air/fuel ratio, it appears it didnt. I didnt have that much time to check everything, but is there any explaination to this. Could i have just not been clamping tight enough. I only let it idle, so i dont know how it would be on the road or under boost.

If its just idling then you wont need the extra fuel. Its when your driving under boost that the extra fuel is needed. You could try restricting the return line and driving under boost, but thats a bit dodgy with vise grips.

Layto....

[Spike_Sierra]

Sorry i should have said, even at idle, the air/fuel gauge showed lean, even tho its in vacuum, which shouldnt mess with the map reading. I will have to make sure its warm and might take it for a spin up the road to see if it makes a difference.

Anyone had any experience with rising rate fuel pressure regs, or even just adjustable ones? Sard ones are over $250, which is a little out of my price bracket on a cheap build. Waiting for ebay auction to finish tomorrow.

[nicbeer]

PM Drew on here re: boosting and fuel regs.

he installed one on his twincharged 4ag

[PJ.zook]

You could add an extra injector with controller but again thats pretty expensive. Theres also the option in low boost situations of fooling the computer with false readings say from the coolant temp sensor if it has one, make it think the engines bloody cold when on boost so it injects more fuel.

[Timbo(Rodeo)]

The way I see it is you have a couple of things in your favour.

You have a fuel pump that can handle much more than the G13BB needs. ie stock flow rate for a VL commo would be much more than a 1.3L 4Cyl. So increasing the fuel pressure shouldn't worry the pump too much.

Secondly, are there any specs for the injectors? flow rate, etc. How about the duty cycle, what sort of numbers are you getting on stock engine at high load?

If there is enough headroom there, then a small amount of boost should be able to be handled by the current setup with the addition of a rising rate fuel pressure regulator.

Assumptions made using theory from here http://autospeed.com/cms/article.html?&A=2619

[Spike_Sierra]

The way I see it is you have a couple of things in your favour.

You have a fuel pump that can handle much more than the G13BB needs. ie stock flow rate for a VL commo would be much more than a 1.3L 4Cyl. So increasing the fuel pressure shouldn't worry the pump too much.

Secondly, are there any specs for the injectors? flow rate, etc. How about the duty cycle, what sort of numbers are you getting on stock engine at high load?

If there is enough headroom there, then a small amount of boost should be able to be handled by the current setup with the addition of a rising rate fuel pressure regulator.

Assumptions made using theory from here http://autospeed.com/cms/article.html?&A=2619

Thanks Timbo for your insight,
1. The Vl pump is the same as the VL turbo pump so i could only assume thats its more than enough to supply the required pressure.
2. Last time i checked the duty cycle of the injectors it was running at 2% at idle and under 40% at full load, so there is enough room in there, however i doubt this figure will change even with the addition of a rising rate pressure reg. as the % is found via the voltage supplied, which is not changing, just the amount that is flowing through each injector opening.

To PJ. This idea is feasable as MART did this with his Supercharger set up, however im not to fond of drilling and tapping another injector/wiring/switching etc as im just unsure of how i would even go about it. I will see if i can adjust the fuel pressure and see if that helps.

When i was clamping the return line, it seemed to stall the engine somewhat, reducing engine rpm, however the airfuel mixture didnt richen.

[BenT]

When i was clamping the return line, it seemed to stall the engine somewhat, reducing engine rpm, however the airfuel mixture didnt richen.

I'd say at idle the exhaust isn't hot enough to keep the O2 sensor in its operating temperature range, so its probably not reading correctly.

Sound like it was richening up if it bogged. You need a fuel pressure gauge in the line to be sure.

You could temporarily clamp the return and take it for a drive to see how it responds. Might run sh*t off boost, but should at least tell you if just raising the fuel pressure is going to help.

Ben

[Spike_Sierra]

Yeah, could be.
I have a mate with a fuel pressure regulator that he said i could borrow to see if it will help my cause.
Will see if i can test it out tonight and will post results.

Cheers for the help.

[Spike_Sierra]

Update: I got a nismo Fuel pressure regulator off a mate and fitted it up.
I wasnt sure if it was a rising rate FPR and it didnt have a pressure gauge so i couldnt test it.
I put it on and tightened it up to restrict fuel flow, and nothing happened except for the engine labouring which is what happened with the dodgy vice grip method( and i know i put it on the right way/line because i had to retighted the hose clamps because of the increased pressure in the lines). The air/fuel ratio gauge still showed L(for lean) this happened when the ratio gets over 20.8:1

So i thought ok, i will just take it for a quick test drive, and it performed alot better, no pinging and no hesitation or flat spot in top gear like there was before.

So now im thinking why isnt the A/F meter working. So i disconected the intake piping from the manifold, and the gauge still read Lean.

Now im stuck in a pickle, is my a/f meter not working, i will have to test the voltage from the o2 sensor tomorrow, to see whats happening at that end. This gauge worked perfectly before the SC setup.

[jonno_racing]

i did say this last night... i dont think the o2 sender isn't compatible or works on different wave lengths..

[Spike_Sierra]

i did say this last night... i dont think the o2 sender isn't compatible or works on different wave lengths..

you did, however how can you explain it working perfectly (stoichiometric 14.7:1) when i first attatched it. And it works on voltages not wave lengths, and the o2 sensor that comes standard with the jimnys is a 4 wire narrow band o2 sensor, 1 neg and signal wire, 1 neg and positive for the heater. They work on a varying voltage signal from .1 to 1v.

taken from autospeed article - Narrow band oxygen sensors usually have one, three or four wiring connections – in the case of the three and four-wire designs, the extra two connections are to power an internal heater. If the sensor has five wires, or is specifically termed a ‘wide-band’ sensor in the manufacturer’s literature, it is not a narrow band design.

[Gwagensteve]

Spike,

Unfortunately, when dealing with EFI motors, the cost isn't ever in the hardware- it's all in the tuning.

Firstly, your oxygen sensor won't ever give you reliable information outside of a very narrow range around stoichiometric. It's not designed as a tuning tool. It's only designed as means of monitoring fueling when other conditions are met - manifold vacuum within X range, throttle position within X range, coolant temperature within X range etc. It can't even read at 20.8:1 as your graph indicates.

You need a wideband O2 sensor in order to have any idea of what the car is really doing. you can build all the interceptors, signal benders etc you like but until you have true wideband O2 sensing, you won't be able to know if they are doing anything - good or bad.

Secondly, your supercharger is way, way, way too small. You're asking it to deliver about twice the air it was designed to. Have a think about it this way. In its home, that supercharger was designed to boost torque. It delivered about 85Nm. Your engine already makes 110Nm. Through the RPM range when you are looking for an increase, the supercharger is already out of flow. You may well be feeling it boost from down low but once your engine is in its working range it can't do much to help.

HP is torque X RPM. If the supercharger is out of flow even trying to match your peak torque, there's no way it's going to build HP.

I'd be looking for a supercharger off a 4AGZE or a 1GGZE. It's better to run an oversized supercharger and gear it down than a too small charger and gear it up.

Eaton type Superchargers, by boosting off idle, place significant tuning demands on the engine. Basically, you can induce high piston loads at very low RPM, which means that the piston sees those high loads for a long time. In an offroad application, even a small RPM point where timing/fuelling is out may result in engine damage. Jimny motors aren't well known for piston strength at the best of times so tread carefully.

The shape of the boosted fuel/timing curve is going to be very different to the N/A one (and different to a turbo curve too) trying to fix it with across the board tuning changes that aren't boost (or even RPM) referenced is never going to work. The rising rate fuel pressure regulator might do the trick, but my guess is you are going to have to figure out how to knock timing out of the motor when it's under boost.

Really though, get a wideband O2 sensor on it before you fiddle with anything else.

Steve.

[Spike_Sierra]

Spike,

Secondly, your supercharger is way, way, way too small. You're asking it to deliver about twice the air it was designed to. Have a think about it this way. In its home, that supercharger was designed to boost torque. It delivered about 85Nm. Your engine already makes 110Nm. Through the RPM range when you are looking for an increase, the supercharger is already out of flow. You may well be feeling it boost from down low but once your engine is in its working range it can't do much to help.

HP is torque X RPM. If the supercharger is out of flow even trying to match your peak torque, there's no way it's going to build HP.

I'd be looking for a supercharger off a 4AGZE or a 1GGZE. It's better to run an oversized supercharger and gear it down than a too small charger and gear it up.

Steve.

Thanks for the info steve,
Couple of questions, this is not having a dig, i actually would like to find out more about flow etc.

Is the supercharger to small even though it sits at 5psi from idle to redline? Is it running out of flow?

I have got another supercharger here, an SC14, but without significant engineering ability like MART has, there is no way that i would be able to fit it in the jimny engine bay along with power steering, and how would one successfully gear down a supercharger. I dont have access to a lathe anymore, and machining of pulleys or even purchasing of pulleys would simply outweigh the benefits. IIRC, MART was running something ridiculous like 17psi at idle with the sc14 in standard trim. The pulleys on the sc14 are quite big already so i would think that quite an increase in pulley size would be needed to gear it down.


On a lighter note, went for another run, with the FPR(im not sure if it is rising rate or not) wound a fair bit in and it seemed to run alot better, with it running lightly rich at idle, and slightly lean at boost, somewhere in the 16-17:1 range. No pinging was present and intake pipes stayed alot cooler. i put another spring in the BOV so it opened fully at idle, reducing intake temps, which probably helped with pinging too.

[Gwagensteve]

I must have missed where you said you are getting 5psi throughout the rev range. If you care getting a nice steady 5 psi and your output temperatures are acceptable, then you might get away with it. If you are getting noticeable heat in the intake piping at idle ~800rpm, imagine the outlet temp at 5500rpm! It would be interesting to know whether the pulley ratio is similar to the stock application or not. Also, it would be interesting to know what's happening to outlet temperatures at prolonged revs.

I'll come back to the original point though, you can't get reliable A/F numbers our of a narrow band sensor, and 16-17:1 is way, way lean under power. I'd suggest you need to be between 12.7-14.7 under boost to be safe.

I'd get a jaycar temp gauge ( K type thermocouple) kit and get it in the intake piping.

I really don't want to be negative, but 5 psi of boost isn't worth killing an engine over. I'd still say get a proper wideband O2 meter on there and maybe measure inlet temps too.

Alternatively, get the car on a dyno and get a proper graph of HP and A/F verses rpm at full load.

Steve.

[GRPABT1]

A turbo and gearing to get it on song would ease alot of these heart aches

[Spike_Sierra]

A turbo and gearing to get it on song would ease alot of these heart aches

How?
I already have gearing.
A turbo would need just as much if not more fueling/ignition changes.
I enjoy building as much as driving, I like fabrication and modifications, usually trying to keep it on a budget as I'm still at uni and have property repayments to keep up with.

[mr green]

A turbo and gearing to get it on song would ease alot of these heart aches

How?
I already have gearing.
A turbo would need just as much if not more fueling/ignition changes.
I enjoy building as much as driving, I like fabrication and modifications, usually trying to keep it on a budget as I'm still at uni and have property repayments to keep up with.

keep up the good work spike, i'm expecting all these dramas when i put the turbo on my already out of wack engine setup. so i'm watching this thread closely and appreciate you nutting most of it out for me

[MART]

Spike , where have you picked up your boost pressure from , in the pick it shows negative boost at idle so are you sure your getting 5 psi through the range.

Also I,m running a centre idler shaft to gear down the charger and it is approx 60 mm from a magna , I joined two together to supply drive to the charger and it still runs too high so I run a bypass tube about 20 mm , plus a blow off valve set to 6 psi.



















































Cheers Paul.

[Spike_Sierra]

Spike , where have you picked up your boost pressure from , in the pick it shows negative boost at idle so are you sure your getting 5 psi through the range.

Cheers Paul.

Thanks for those pics paul.

I run the boost gauge to a vacuum port on the manifold, nothing else is connected to this.

Its getting negative boost(vacuum) at idle becuase the throttle is closed and the BOV(bypass valve) is open, recirculating the air back into the inlet pipes. This only changed about 3hg/m after fitting supercharger.
From what i can tell, looking at the gauge, its a constant 5psi.
What does yours get at idle, throttle shut?

How have you effectively tuned yours to cope with the extra pressure?
I have been searching for some dyno tuners that will allow use on their rollers for tuning purposes.
Do you have any vids of yours in action so i can see how loud it is. Mine is only marginally louder than a standard motor now everything is plumbed up and the BOV is opening fully.

[MART]

At idle I run 0 psi , and up to 5 at full throttle through to 6500 to 7000 rpm , mine is a little different to yours as I have the head fully ported and the cam reground to suit a blower or forced induction. Cruising from stockton from sydney , about 200km each way travelling mainly at 100 it used 23 litres of premium and that's pushing 35's so not to bad. It runs at about half temp and has only gone a little higher while sand driving. Heat doesn't really affect it , Cheers Paul.

[alien]

so you guys are getting better fuel economy from the charger??? most of the time i've seen turbo's and chargers its lowered the fuel economy? (most likely cos theyre enjoying the new found power though).

[Hybrid]

23 litres to 200km = 11.5l per 100km. That's pretty standard isn't it? I wouldn't say its better fuel economy.

[david123]

23 litres to 200km = 11.5l per 100km. That's pretty standard isn't it? I wouldn't say its better fuel economy.

Crikey, wish I got that good outa me toy.

Recon at a road steady speed of 80k on the clock, not sure of actual speed, im at around 14lph.

Me V8 Statesman with over 300kw gets around 10lph at highway speeds, but she don't go like the powers of piss off the track.

Me vitara is about 7-7.5 at around 100kph highway use.

[Spike_Sierra]

Spike , where have you picked up your boost pressure from , in the pick it shows negative boost at idle so are you sure your getting 5 psi through the range.

Cheers Paul.

Im still not understanding this very well.

Where are you picking up your boost level from. You must be getting it pre throttle, otherwise it would be idling high if it was manifold.

Do you have any vids of yours in action, engine bay or even outside shots.

How have you effectively tuned it?

[GRPABT1]

A turbo and gearing to get it on song would ease alot of these heart aches

How?
I already have gearing.
A turbo would need just as much if not more fueling/ignition changes.
I enjoy building as much as driving, I like fabrication and modifications, usually trying to keep it on a budget as I'm still at uni and have property repayments to keep up with.

You'd have less troubles with space and it'd be making more power on less boost and hence less engine damage and tuning/fuel requirements and would be more reliable IMHO. Gearing would just help it be on boost offroad.

[cj]

it'd be making more power on less boost and hence less engine damage and tuning/fuel requirements and would be more reliable IMHO.

How do you get more power with less boost?

[Spike_Sierra]

A turbo and gearing to get it on song would ease alot of these heart aches

How?
I already have gearing.
A turbo would need just as much if not more fueling/ignition changes.
I enjoy building as much as driving, I like fabrication and modifications, usually trying to keep it on a budget as I'm still at uni and have property repayments to keep up with.

You'd have less troubles with space and it'd be making more power on less boost and hence less engine damage and tuning/fuel requirements and would be more reliable IMHO. Gearing would just help it be on boost offroad.

Thank you for your helpful reply

couple of questions:
1. How am i having space troubles now? The supercharger is already fitted and is making full boost all the way through the rev range therefore not needing to 'upgrade' to a bigger supercharger.

2.How would it be making more power on less boost? The resistance in spinning the supercharger it more then made up for in instant boost off idle.

3.How would there be less tuning requirements with a turbo, it would be exactly the same even if i was running 'less boost'. Also there would be no point to put on any form of forced induction and run less than 5psi.

4. As i mentioned before, i already have gearing, and as the supercharger is on boost off idle, a supercharger would be better offroad due to no lag.

Also did you think about the cost of custom exhaust manifolds, turbo, oil and water lines tapped into block, along with more piping, possibly intercooler.

Seriously, if your not going to think about you answers before you post, then just sit back and play with yourself.
This thread was started as a pure tech thread to help others like me enjoy boosting relatively cheaply. If you have something worthwhile, then please go ahead and post it up. Im not about to go radically changing my plans for no reason....

[Gwagensteve]

Yep, you're off track GRPABT1. Starting over with a turbo would result in all the hassles of a turbo installation exactly the same tuning problems spike has to deal with now, and ultimately a less suitable engine for most off road work.

I know, I have an engine that's less suitable for off road work than a supercharged 1.3

Spike, (and I'm not bagging you or being negative) until you can provide some supercharger outlet temperatures, I'm still going to say your 'charger is too small. That's not super relevant right now, it's far more important to get control of the tuning. However, I'm going to compare with something like the Mini Cooper S we had and say there was no significant inlet temperature rise until the engine was well into its power. Those eaton type superchargers are quite efficient and lots of them are run without intercooling (like in the V6 commodore) so seeing heat at idle isn't acceptable.

Anyway, that's beside the point. There's some good tech going on here, thanks for the work you are doing to post the process you are going through.

Steve.

[GRPABT1]

I was speaking from the point of starting from the start not binning it all and going turbo. I researched supercharging my GTi motor long ago and the AMR300 I found was way to small, which I am willing to bet you will find out eventually one way or another. Also the custom parts you speak of like turbo manifolds, etc can be found for bugger all of redlinegti and it's a simple flange swap.

And I don't care how well your setup goes now it will never make as much power as a turbo could, yes its tourque curve will be flatter and make more torque down low hence it will be better if you sit on 500rpm all the time off road. But if you're like me with decent gearing then whenever you need power to overcome and obsticle then you are giving it a few revs anyway and a turbo on song will make more torque at the same revs (when on boost) as a blower with less load to the engine.

A blower takes engine power to run and a turbo does not, hence why I said that a turbo will make more power at the same boost, especially your puny blower. HP is torque X revs and I'm willing to bet up high in the revs where suzuki motors can go your blower is running out of puff. So in affect I still stand by the theory a turbo will make more HP than a blower overall on the same psi, however slight that power difference may be in such a small application.