Carb to EFI Conversion

[ajg193]

Hello,

I have a car (1983 Toyota Starlet) which I converted from carburetor to EFI using components from a JDM Starlet of the same vintage (but with modern sensors and aftermarket ECU).

As a part of the modification I fitted one soft fuel hose from the fuel up at the fuel tank to the engine bay. The mounts are utilizing the original fuel hose mounts, as well as added P clamps between these mounts wherever the spacing was greater than 300 mm.

Power output of the engine is approximately the same as with the carburetor, brochures for the JDM Starlet list the power as 58 kW, while the NZDM Starlet has 49 kW from factory, this represents an increase of potentially 18%. However, the NZDM 4K engine has a compression ratio of only 9.0:1, while the JDM 4K-E engine has a compression ratio of 9.5:1 so I would not expect to see a gain of 18% with just converting to EFI. Internally the engine is maintained to factory NZDM specifications.


No structural modifications have been made to the vehicle, a hole was drilled in the original exhaust system for an O2 sensor.

The fuel pump was just T'd into the existing fuel line from the tank, no modifications to the tank or original fuel hose within the vehicle. The original hose is just being used as a return path to the pump. (I've done about 12,000 km in the 7 months since doing the conversion and have had no issues with fuel starvation or cavitation.)

Last week I failed a WoF (it passed last time) at VTNZ for the modification with the inspector stating it is a change of induction and therefore requires a certification.

I visited the local certifier here in Christchurch and he agrees that the car needs a certification.

However, speaking with Clint Field (not sure if I should name people here), he believes that the modification does not require a certification.


The car is booked in for a certification on Monday morning (16/4/18) and I would like a clear answer before that time as to whether or not the car does need a certification for this modification as I would prefer to not spend $560 if I don't need to.



Thank you

[Todd]

Hi there,

It sounds like this question was already answered away from this forum.

[ajg193]

Not quite answered yet, but I'm sure I will have a final answer in the next few days. Ian Smith called me yesterday afternoon saying he is no longer certain whether it needed a cert and to take the car home for the time being and the LVVTA are currently discussing the case internally.

Thanks

[ajg193]

Just an update:

Ian didn't want to certify the car as it does not exceed the limits specified within the VIRM.

I took the car back to VTNZ, they demanded I prove the power is less than 20% increase. I went back with a three page engineering report + appendices from multiple brochures and they gave me the WoF.


----
So the outcome of this case is: Converting a car from carburetor to EFI in New Zealand is acceptable under current law without an LVV cert.

[Todd]

Good to hear. It's an interesting situation, as generally a conversion like this exceeds the threshold in different ways, so almost always requires certification.