Building a 2270 motor with LH-Jet, A discussion thread.... Options

[boxsterfan]

I can't help but wonder about the Megasquirt (or even Microsquirt) thing. You are looking at doing something that hasn't been done much, vs what has - and has been proven. It sounds like you think MS is complicated and you are afraid of it, when it seems to me it is simple and proven?

But I love it that you are looking at something new. Always love to see that. Look forward to hearing what you end up with.

No afraid of MegaSquirt, just daring to be different.

[Rand]

I can't help but wonder about the Megasquirt (or even Microsquirt) thing. You are looking at doing something that hasn't been done much, vs what has - and has been proven. It sounds like you think MS is complicated and you are afraid of it, when it seems to me it is simple and proven?

But I love it that you are looking at something new. Always love to see that. Look forward to hearing what you end up with.

No afraid of MegaSquirt, just daring to be different.

Like I said, prove us wrong and I will love it. But you are bucking the system.

[boxsterfan]

I can't help but wonder about the Megasquirt (or even Microsquirt) thing. You are looking at doing something that hasn't been done much, vs what has - and has been proven. It sounds like you think MS is complicated and you are afraid of it, when it seems to me it is simple and proven?

But I love it that you are looking at something new. Always love to see that. Look forward to hearing what you end up with.

No afraid of MegaSquirt, just daring to be different.

Like I said, prove us wrong and I will love it. But you are bucking the system.

Yes, I am bucking the system. Thank you Captain Obvious.

[edwin]

As far as programmability are there any lh2.2 cars that can do more than EPROM chips for tuning?

[Jake Raby]

The issue with this is the compromises that are made when equipping a larger engine with stock FI. The added displacement won't offer any more power due to the constraints placed on it by the stock FI.

You will find it challenging to have stable AFR across the entire RPM range. If you have low enough standards, and are open to compromise, by all means, proceed. After 2056cc I determined the law of diminishing becomes common place with stock FI.

In the late 90s I built quite a few 2270 engines with stock FI, narrow power bands and tuning challenges is how I'd define them.

[r_towle]

The issue with this is the compromises that are made when equipping a larger engine with stock FI. The added displacement won't offer any more power due to the constraints placed on it by the stock FI.

You will find it challenging to have stable AFR across the entire RPM range. If you have low enough standards, and are open to compromise, by all means, proceed. After 2056cc I determined the law of diminishing becomes common place with stock FI.

In the late 90s I built quite a few 2270 engines with stock FI, narrow power bands and tuning challenges is how I'd define them.

Did you ever try EFi I from a larger motor?
I believe he is talking about gathering all the parts from a different LH jet motor that may be in the range of his motor....so it would be stock! but not stock 914.....

[Jake Raby]

Yes, both ways.

[boxsterfan]

Where can I find information on keeping the proper ratios for the size of the intake/plenum and runners as it relates to the size of the motor?


Note: I didn't take flow dynamics in college. (IMG:style_emoticons/default/shades.gif)

[skeates]

Where can I find information on keeping the proper ratios for the size of the intake/plenum and runners as it relates to the size of the motor?


Note: I didn't take flow dynamics in college. (IMG:style_emoticons/default/shades.gif)

I'd imagine that these days a simple google search would get you what you need on that front. If not, I've got one of them fancy college text books with all that information in it. I can look into scanning the bits that you would need (though be warned that the book has a habit of breaking out into a flurry of formula and greek symbols from time to time).

Regarding the fuel injection system decisions, I would recommend going the route which gives you the most control over your motor. It seems to me that the limiting factor here is the ecu more so than the FI sensors. A fully programmable ECU should be able to handle a myriad of sensor options. A few have been mentioned here already (including Megasquirt), but it sounds like you are more interested in problem solving than in applying something proven (which is fantastic by the way!). Some other options you might check into are piggy-back ecu controllers and/or aftermarket software for your ecu which would allow you to program it. At the end of the day I doubt you will be satisfied with your set-up if you can't tune it to your motor. Cam profiles, intake and exhaust plumbing, motor displacement, etc. all play massive roles in tuning. Even if someone else sends you a map for their Type IV engine your engine's needs will likely be quite different! So, my .02 is that whatever you end up with ecu wise that you have full control over your timing, and fuel maps!

[MrKona]

LH-Jet 2.2 cold start valve is controlled by the ECU with input from the coolant temp sensor. There is no thermo time switch. If sticking with the original ECU, what signal could be used as an input in lieu of the coolant temp sensor?

[r_towle]

LH-Jet 2.2 cold start valve is controlled by the ECU with input from the coolant temp sensor. There is no thermo time switch. If sticking with the original ECU, what signal could be used as an input in lieu of the coolant temp sensor?

CHT could provide the input, but you would need to design some electronics to bring the CHt readings inline with a coolant temp sensor.

Coolant gets to what...180 degrees..
A CHt can get to 380....

Probably need to figure t what a coolant temp sensor reads at different temps on the stove..

[MrKona]

LH-Jet 2.2 cold start valve is controlled by the ECU with input from the coolant temp sensor. There is no thermo time switch. If sticking with the original ECU, what signal could be used as an input in lieu of the coolant temp sensor?

CHT could provide the input, but you would need to design some electronics to bring the CHt readings inline with a coolant temp sensor.

Coolant gets to what...180 degrees..
A CHt can get to 380....

Probably need to figure t what a coolant temp sensor reads at different temps on the stove..

Any thoughts about the oil temp sensor at the taco plate?

[r_towle]

It's all Ohms and electronics...
It could be done, just need to know the target ohms for the stock coolant sensor.

The fuel maps should be published somewhere for whatever ECU you pick...

[Dave_Darling]

I am told that oil typically takes twice as long to come up to temp as (water) coolant does.

--DD

[r_towle]

I am told that oil typically takes twice as long to come up to temp as (water) coolant does.

--DD

Other way around.

Oil heats up faster than water..

But for an oil cooled motor...it might actually be appropriate.

[colingreene]

I really don't think that that is at all true.
Oil in my experience has always taken longer to heat then the water temp.

[Rleog]

The specific heat capacity of water is 1 cal/gm-deg C, which, in comparison to most other substances, is very high. Mineral oil has a specific heat ~ 0.4, which is likely not much different than motor oil. Higher specific heat substances 'hold' more heat. Oil would warm up more quickly.

[Jake Raby]

Insude the engine, things change. This is the reason why modern Porsche engines include a heat exchanger. The job of the heat exchanger is to assist the oil in reaching temperature faster, by using the coolant and it's temperature as a catalyst.

In hotter temps or when high RPM (and the friction it produces) exists, the heat exchanger serves a secondary purpose by keeping the oil temperatures cooler, and closer to the coolant temperatures.

In my research, even with the heat exchanger fitted it still takes 2-4x as long for oil temperatures to reach that of coolant temperatures of 180F. The oil being used and which engine it is applied to as well as ambient temps all make huge impacts.

In an Aircooled engine the heads will reach temperature within just a couple minutes of loaded operation, according to rPM and ambient temperature the oil may take several X longer to reach 180F, and in some ambient conditions it may never reach optimum temperature.

The behavior of oil in a coolant cooled engine and an Aircooled engine is vastly different.