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

[boxsterfan]

First off, I am not anywhere near an expert in engine building, cam selection (how duration and lift affect the motor at idle and driving), injector flow rates, etc, etc, etc... So now that I have that out of the way, I still want to figure out the bits and parts that ***may*** make it possible to run a 2270 motor with LH-Jet. The primary reasons I am looking at this setup are because:

• L-Jet likely is not a good setup for this based upon my reading (issues with cam, idle troubles, hesitation, full power, etc...).
• I don't want to run carbs.
• I don't believe I want to tackle MegaSquirt (leaving the door open though).
• It sounds like fun/dare to be different.

1. The first question that comes to mind is will it be LH-Jet 1.0 vs LH-Jet 2.0?
From my research, LH-Jet 1.0 was pretty rare and used in the early 80's but then a switch to LH-Jet 2.0 occured. The primary difference between the two was that LH-Jet 2.0 utilized a Throttle Position Sensor (TPS) whereas LH-Jet 1.0 did not.

2. If LH-Jet 2.0 variant is the desired setup, which sub-variant would be used?
There appears to be a couple sub-variants within LH-Jet 2.0 primarily consisting of LH-Jet 2.2 and LH-Jet 2.4. It appears one of the primary differences between the two is that the LH-Jet 2.4 utilizes a "trigger flywheel" and the LH-Jet 2.2 does not. What exactly a "trigger flywheel" is I am not sure....I am guess that this is a notch or mark on the flywheel that is monitored by a sensor with the data fed back to the ECU.

3. What would the "build" sheet look like for such a setup?

Of course, this list can get complicated, but the desired build here is a street car with spirited driving. I would want excellent low-end torque, around 140-150HP on the motor and good pull all the way through the RPM range up to XXXX RPM (not sure where redline would be). Note also, the car will remain as a narrow body with 4-lug wheels.

• 2270 motor with which CAM?
• What plenum could work here?
• What intake runners would work here?
• Which fuel injectors could work here?
• Need to upgrade fuel pump?
• ECU - need to pull from Volvo/Saab from 80's
• FI Wiring Harness - need to pull from Volvo/Saab from 80's and will require customization
• Need any relay boards?
• Hot-wire MAF Sensor - need to pull from Volvo/Saab LH-Jet system
• IAC - Electronic Idle Controller - need to pull from Volvo/Saab from 80's
• O2 Sensor - need to pull from Volvo/Saab from the 80's - where to mount?
• CHTS - Utilize the existing CHTS (TS2) input into the ECU as a substitute for the coolant temp sensor (just have to figure out the proper resistance)
• Cold Start Valve - probably not needed here in the Bay, but what could be done here? Or does existing on the Type IV motor work here?

Of course, if you have already done this setup, it would be great to here from you, how the car drives, pain points, etc, etc....

[Dave_Darling]

Your best bet is to find a four-cylinder car that had about a 2.3L displacement and made about 150 HP that ran LH-jet. Then just use all the parts from it that you can.

My guess is you'll have to actually use something from a larger displacement motor than 2270cc, because I don't think there were a lot of 2.3L motors back when LH-jet was popular that made as much as 150 HP... Especially four-bangers.

Cam, heads, intake, and exhaust all have to work together.

I'm thinking you may be able to use the stock 2.0 manifold and such, but you'll have to make mods to fit the parts from the donor car--like injectors.

A header of some kind is probably the best idea for exhaust. Ideally, use a Tangerine piece. But any header setup will have a collector that will (eventually) get gases from all four exhaust ports, so that's a good place to put your O2 sensor.

The relay board in an L-jet 914 is mostly there to hold the voltage regulator and to attach the main wiring harness to the FI wiring harness and engine wiring harness. The actual FI relays are elsewhere, generally hanging off the battery tray. You can follow that model pretty easily if you choose.

Use the fuel pump from your donor car, or double-check the required volume and pressure for the donor car's pump. And get a pump that meets or exceeds those. (The stock 914 pump might be that pump, or you might need to get something like a Walbro pump.)

Sounds like an interesting project, that's for sure!

User ejm (Ed, who works for Racer Chris) put a CIS setup on his 1.8 turbo; I think some of the challenges in that would be similar to the ones you will be facing. So he may have some good input on that.

--DD

[r_towle]

Your best bet is to find a four-cylinder car that had about a 2.3L displacement and made about 150 HP that ran LH-jet. Then just use all the parts from it that you can.


--DD

Agreed on that.

The big difference between L-jet and LH-jet is the O2 sensor with a feedback loop for constant monitoring of the mixture.

Look at the 924/944 motors, I cannot remember the sizes, but those systems may work, and have support in the aftermarket.

The other one is VW (rabiit/golf/jetta etc) which has a large aftermarket support community.

Rich

[boxsterfan]

Your best bet is to find a four-cylinder car that had about a 2.3L displacement and made about 150 HP that ran LH-jet. Then just use all the parts from it that you can.


--DD

Agreed on that.

The big difference between L-jet and LH-jet is the O2 sensor with a feedback loop for constant monitoring of the mixture.

Look at the 924/944 motors, I cannot remember the sizes, but those systems may work, and have support in the aftermarket.

The other one is VW (rabiit/golf/jetta etc) which has a large aftermarket support community.

Rich

The O2 sensor is a difference but also the air flow meter is a "hot wire" unit vs. the barn-door L-Jet AFM's.

There are definitely 4-cylinder NA Volvo's running around 150-160 HP (B230FT motor for example).