Bike Carbs or Fuel Injection???

RossH

RossH

Early Euro Spec 1500
Hi All,

Just looking to canvas opinion on the above two options.

I`m busy with a 1600 stroker build at the moment, with a BV head and hot ish cam etc.

The original thought (for reasons of budgetary limitations) was to mod my existing Weber 34, as per the PBS book. Upon taking the carb to the local specialist, it turns out that its in pretty bad shape so I need to make another plan. The modded 34 was going to be an interim option to get up and running, and wouldn`t have been the ideal solution by any means. So now that thats ruled out, I`m looking at alternative options and just implementing the long term solution. The budget is long blown anyway...so what the hell!!!

After doing a fair bit of reading it seems that good results can be had with bike carbs. On the strength of that I found a set of 40mm Keilin bike carbs off a low milage ZX9 on ebay, for a very reasonable price, and have found a local fabricator who can make up the inlet manifold. The Keilin carbs should be here next week.

In the mean time another potential option has popped up, and I will sell the bike carbs on if I go this route. I can get the inlet manifold from an Uno Turbo for literally next to nothing. This is pretty much the same design as the US 1500 FI inlet manifold. While the the manifold itself will be very cheap, it is stripped of all the ancillaries. I`m still trying to get my head around all the bits I would need to make an FI setup work, but I think essentially I would need the following:

Injectors
Fuel Rail
Throttle body
High Pressure Injection Pump
Mod to existing fuel tank?
TPS
MAP
Lambda sensor
Some form of Engine Management System

Sourcing all of the above is likely to be quite an exercise, with a fairly substantial price tag, and many hours of labor!

So the big question is, is the additional expense and installation time of the FI option likely to be justified in terms of performance, over the simpler and cheaper bike carb option???

Any thoughts and opinions welcome!!!

Thanks,

Ross
 
Parts List

Hi Ross,

I can't comment of the benefits of one vs. the other, but I can provide some feedback as to what you will require.

First of all, you will need to "notch" your existing head (assuming it is a carb head) to ensure the flow pattern from the injectors is not interrupted.

In terms of parts, you won't need a MAP sensor (at least, not with L-Jetronic). The TPS (again assumping Bosch) is not a real TPS but rather micro switches detecting "no throttle" and "full throttle".

You will need an additional coolant sensor in the thermostat housing, a wiring harness, idle control valve and an air flow meter.

The Bosch L-Jetronic is probably the easiest for this application but won't give you the performance that you might get from a properly tuned Megasquirt or similar.

Cheers,
Dom.

RossH said:
Injectors
Fuel Rail
Throttle body
High Pressure Injection Pump
Mod to existing fuel tank?
TPS
MAP
Lambda sensor
Some form of Engine Management System
Click to expand...
 
Cheers Dom,

Thanks for your input!

The relative simplicity of the bike carb route is quite appealing, although I guess there is also something to be said for modernizing the motor as well....
 
both?

I am planning on doing a ITB swap on my Honda b16 I am putting in my fiat. Using GSXR Throttle bodies. I personally would do a megasquirt conversion if I were going to use the fiat engine.


Odie
 
Stock FI manifold

From my research for my 1600 engine, I understand that the stock FI manifold is small for a 1600 engine, and there is not enough thickness to port it. What I have heard, I have not measured it and others may say different.

I am still exploring options.

Paul Davock
 
I'm 95% done with fabrication on the bike carb setup, but ran out of time to test and dyno before our race so we're sticking with the 34 dmtr.

I'm only doing this becasue of budget reasons (I can even swap a good 34 dmtr for the complete bike carb setup).

I would go megasquirt / junkyard parts for a more modern FI solution if I had around $600 to spend on a system.
 
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