Thread: My 2.25L series 2a gets EFI and a Supercharger!

hey Subasurf and Rangier,
I know EXACTLY how my gearbox is going to hold up...... NOT WELL!
over a year ago I believed I was having trouble with my advance sticking at higher revs. It would cut out when I backed off the throttle, wait until I opened the throttle back to where it was, and BAM! it would cut back in again, with a rather un-delightful backlash through the gearbox. Within a few days my 3rd gear developed a rather ratchet-like noise. I dumped the gearbox oil and remember thinking it would make fantastic metallic-black nailpolish! I also found a gear-tooth, a ball-bearing (just a single ball) and some small shrapnel in the oil-tray. I threw some fresh oil in, and over a year later (and not thrashing the box) it hasn't got any worse!! A few weeks ago I changed the gear oil and it was still quite golden

I have a 2a gearbox sitting in my folks' shed waiting for the next time I'm up that way with some spare time. I'm going to throw the 2a in as an interim, while I rebuild the S3 box (it also needs new detent springs, but what series box doesn't!)

BUT, once I have my S3 box happily back in there, I believe it will handle the job well. This project is not about how much power I can milk from the old 2.25, its about efficiency (.....yes, I'll keep telling myself that! )
The EFI is to ensure my air:fuel ratios are spot-on and my ignition timing is right where I want it, and the supercharger is to overcome the terrible flow of the inlet manifold and head. I'm only boosting things by 5psi (atmospheric is around 15psi) so this is just pushing my air/fuel mixture into the cylinders, rather than relying solely upon the intake stroke to suck it in through the poor-flowing manifold/head.

I understand your point, thrashing around with that power could chew through a gearbox pretty quickly. Believe me, I have a dune-buggy running a 4.4L P76 V8 through a completely stock 1600 Kombi box that myself and my girlfriend built out of two shagged ones that came with it. The old owners used to drop in a box and do wheelies on the bitumen until first gear gave way But since we rebuilt that box, we've just been taking it easy and being careful where we use the power, and I expect it will serve the V8 well for some time.
(for interest's sake, check it out here [ame="http://www.youtube.com/watch?v=xRVLSwNmu5Q"]YouTube- V8 Dune Buggy first run: donut and un-intentional wheelie in the paddock[/ame] )

As I said earlier, I'm only really going to be cruising around with Bruce, and any 4WDing is going to be quite light, and ESPECIALLY not at full torque. A standard S3 box will be adequate for Bruce, but I agree, certainly NO towing horse-floats up hills with the overdrive!!

Originally Posted by SeriesKid

hey Subasurf and Rangier,
I know EXACTLY how my gearbox is going to hold up...... NOT WELL!
over a year ago I believed I was having trouble with my advance sticking at higher revs. It would cut out when I backed off the throttle, wait until I opened the throttle back to where it was, and BAM! it would cut back in again, with a rather un-delightful backlash through the gearbox. Within a few days my 3rd gear developed a rather ratchet-like noise. I dumped the gearbox oil and remember thinking it would make fantastic metallic-black nailpolish! I also found a gear-tooth, a ball-bearing (just a single ball) and some small shrapnel in the oil-tray. I threw some fresh oil in, and over a year later (and not thrashing the box) it hasn't got any worse!! A few weeks ago I changed the gear oil and it was still quite golden

I have a 2a gearbox sitting in my folks' shed waiting for the next time I'm up that way with some spare time. I'm going to throw the 2a in as an interim, while I rebuild the S3 box (it also needs new detent springs, but what series box doesn't!)

BUT, once I have my S3 box happily back in there, I believe it will handle the job well. This project is not about how much power I can milk from the old 2.25, its about efficiency (.....yes, I'll keep telling myself that! )
The EFI is to ensure my air:fuel ratios are spot-on and my ignition timing is right where I want it, and the supercharger is to overcome the terrible flow of the inlet manifold and head. I'm only boosting things by 5psi (atmospheric is around 15psi) so this is just pushing my air/fuel mixture into the cylinders, rather than relying solely upon the intake stroke to suck it in through the poor-flowing manifold/head.

I understand your point, thrashing around with that power could chew through a gearbox pretty quickly. Believe me, I have a dune-buggy running a 4.4L P76 V8 through a completely stock 1600 Kombi box that myself and my girlfriend built out of two shagged ones that came with it. The old owners used to drop in a box and do wheelies on the bitumen until first gear gave way But since we rebuilt that box, we've just been taking it easy and being careful where we use the power, and I expect it will serve the V8 well for some time.
(for interest's sake, check it out here YouTube- V8 Dune Buggy first run: donut and un-intentional wheelie in the paddock )

As I said earlier, I'm only really going to be cruising around with Bruce, and any 4WDing is going to be quite light, and ESPECIALLY not at full torque. A standard S3 box will be adequate for Bruce, but I agree, certainly NO towing horse-floats up hills with the overdrive!!

Don't think that just because you are pushing the intake charge in with a blower you will achieve high volumetric efficiency. Restriction is restriction whether under vacuum or under pressure. You will still need to clean out the ports, and the manifold as far as you can reach, port match the manifolds to the head, do the tricky stuff around the valve heads and seats and attempt to unshroud the valves in the combustion chambers as much as you can.

Have a look at the manifold design and think about whether you are going to get even fuel distribution. This can cause major problems with pressurised engines. You may need to fabricate a one into two into two x two manifold system to achieve this.

Supercharging engines not designed that way can be a complex and frustrating business. Two steps forward and one step back, or sometimes the other way around as you work your way through the problems encountered.

Hi Brian,
Thanks for the comment.
The whole purpose of forced induction on an internal-combustion engine is to increase the volumetric efficiency. You are creating a "virtual displacement increase" - More air/fuel in (mixed with correct ignition timing) = more power.

When the inlet valve opens and the piston moves down (creating a larger volume), air needs to fill this space. It is the difference in air-pressure between that of the cylinder (lower pressure) and that in the manifold (higher pressure) that causes air to flow through the head to fill the cylinder. The flow-rate of air entering the cylinder relies upon three MAIN variables:
1: Rate of volume "created" inside the cylinder.
2: The difference in pressure between the cylinder and the manifold.
3: The cross-section and surface that this air has to flow through.

While yes, your suggestions (relating to the third variable) are good and will increase the flow, unless they are taken to extremes they will not bring the volumetric effiency anywhere near 100%. The manifolds and heads would need to flow faster that the piston can "create" the volume. Also, I cannot do this work myself, which equalls more $$ (this is a VERY low budget project)

Forced induction relies upon the second variable. By increasing the pressure in the manifold, there is a greater difference in pressure between the manifold and the cylinder, thus - greater flow-rate. Greater flow-rate over the same period of time = More air/fuel in the cylinder = higher volumetric effieciency.
Yes, restrictions are restrictions, but they only SLOW flow by a proportional ammount, NOT limit it. All I need to do to get more in the cylinder is turn up the boost.

As you increase the boost level you will approach 100% volumetric effiency. As you CONTINUE to raise the boost level it moves into the >100% region.

On the 1-2-4 inlet manifold front, I will be running sequential injection: 1 injector per inlet, just before the inlet, and timed to fire just after the inlet valve begins to open.

The main thing to remember here is that I am already converting to EFI for efficiency and tunability. I am doing this VERY cheaply and doing almost all of the work myself (exeption: the preperation of the inlet manifold for the injectors).

Once this is done, supercharging is the best performance per dollar improvement I can make. I don't even need to retune the ECU, as I'm using Manifold Air Pressure for mapping.
Toyota SC14 supercharger = $250
Plumbing = $50
Custom pully = $80
Home-made bracket = $5
TOTAL = $385

I can vary the boost anywhere between 5 and 15psi, and with the flick of a switch I can disable the supercharger and have a normal Bruce. And down the track I can take all this off and put it on almost ANY other car, leaving Bruce just as he is now

Originally Posted by SeriesKid

Hi Brian,
Thanks for the comment.
The whole purpose of forced induction on an internal-combustion engine is to increase the volumetric efficiency. You are creating a "virtual displacement increase" - More air/fuel in (mixed with correct ignition timing) = more power.

When the inlet valve opens and the piston moves down (creating a larger volume), air needs to fill this space. It is the difference in air-pressure between that of the cylinder (lower pressure) and that in the manifold (higher pressure) that causes air to flow through the head to fill the cylinder. The flow-rate of air entering the cylinder relies upon three MAIN variables:
1: Rate of volume "created" inside the cylinder.
2: The difference in pressure between the cylinder and the manifold.
3: The cross-section and surface that this air has to flow through.

While yes, your suggestions (relating to the third variable) are good and will increase the flow, unless they are taken to extremes they will not bring the volumetric effiency anywhere near 100%. The manifolds and heads would need to flow faster that the piston can "create" the volume. Also, I cannot do this work myself, which equalls more $$ (this is a VERY low budget project)

Forced induction relies upon the second variable. By increasing the pressure in the manifold, there is a greater difference in pressure between the manifold and the cylinder, thus - greater flow-rate. Greater flow-rate over the same period of time = More air/fuel in the cylinder = higher volumetric effieciency.
Yes, restrictions are restrictions, but they only SLOW flow by a proportional ammount, NOT limit it. All I need to do to get more in the cylinder is turn up the boost.

As you increase the boost level you will approach 100% volumetric effiency. As you CONTINUE to raise the boost level it moves into the >100% region.

On the 1-2-4 inlet manifold front, I will be running sequential injection: 1 injector per inlet, just before the inlet, and timed to fire just after the inlet valve begins to open.

The main thing to remember here is that I am already converting to EFI for efficiency and tunability. I am doing this VERY cheaply and doing almost all of the work myself (exeption: the preperation of the inlet manifold for the injectors).

Once this is done, supercharging is the best performance per dollar improvement I can make. I don't even need to retune the ECU, as I'm using Manifold Air Pressure for mapping.
Toyota SC14 supercharger = $250
Plumbing = $50
Custom pully = $80
Home-made bracket = $5
TOTAL = $385

I can vary the boost anywhere between 5 and 15psi, and with the flick of a switch I can disable the supercharger and have a normal Bruce. And down the track I can take all this off and put it on almost ANY other car, leaving Bruce just as he is now

Thermal spots and detonation will be your biggest worry. Same reason I'm treading around putting a blower on my Rangie only my choice of blower are real bad for it

That 4.4 powered dak dak I have one of those as well If you make a clamp for either side of the trans axle out of 1/2" plate and some long bolts or threaded bar they will take some The VW casing is made of iron filings and cheese Also peg the cwp if your clever Stops all the flexing from the torque. The Vee wee steel is quite good then

Yes but with a restrictive intake you'll need more pressure to get the same VE as a smooth flowing setup. more pressure means more robbed horse power and much higher intake charge temps. Higher temps will lead to timing issues which will rob power and effiency.

Also - nobody has ever used "blower" and "effiency" in the same sentance before, ever.

Why not custom make a tuned length intake manifold with proper sized plenum?

Originally Posted by Hardchina

Yes but with a restrictive intake you'll need more pressure to get the same VE as a smooth flowing setup. more pressure means more robbed horse power and much higher intake charge temps. Higher temps will lead to timing issues which will rob power and effiency.

Also - nobody has ever used "blower" and "effiency" in the same sentance before, ever.

Why not custom make a tuned length intake manifold with proper sized plenum?

Even if he used 2.25 the diesel manifold it would exceed the flow required although wont create the ram effect of a custom made intake ram tubes and plenum. I think the port velocity caused by the forced induction with the standard 2.25 head would be impressive. He's only planing for low boost so should be fine. It's not a drag car and never will be.

Originally Posted by SeriesKid

project)

Forced induction relies upon the second variable. By increasing the pressure in the manifold, there is a greater difference in pressure between the manifold and the cylinder, thus - greater flow-rate. Greater flow-rate over the same period of time = More air/fuel in the cylinder = higher volumetric effieciency.
Yes, restrictions are restrictions, but they only SLOW flow by a proportional ammount, NOT limit it. All I need to do to get more in the cylinder is turn up the boost.

As you increase the boost level you will approach 100% volumetric effiency. As you CONTINUE to raise the boost level it moves into the >100% region.

On the 1-2-4 inlet manifold front, I will be running sequential injection: 1 injector per inlet, just before the inlet, and timed to fire just after the inlet valve begins to open.

theres a minor flaw in your theories as youve laid it out and that involves your fuel ratio.

while admitedly usually only a problem for turbo engines you still need to watch the change in your airflow at different revs and compensate for it in your mapping or you are going to run lean and hot which will definately take out the exhaust valves or run rich and cold which will pooch your bores and rings.

Hi Blknight,
That's what 3D mapping is for