# 1.8 Intake manifold confusion?



## Mr_Efficiency (May 7, 2008)

I have a 93 Golf I race at my local oval track. I was taking the engine apart today and I ran into a few things in the intake manifold I didn't know what to make of.
First, what is the circular thing with all the little fingers sticking out of it bolted into the bottom of the intake manifold? It has a wire going to it. What does it do? Would it hurt or help performance if I removed all the little fingers until it was flush with the rest of the intake manifold and bolted it back in. Probly remove the wire as well. I dont care much for drivability since the car only sees idle and WOT (3500-6000 rpm)
Second, Is there a larger throttle body for these? The current one is rediculously small. Also I was thinking of doubling up the spacers between the bottom and top half of the throttle body (between the throttle plate and injector housing)
Is the fuel pressure regulator adjustable? its looks like it but i dont want to play with it until I know what I'm getting myself into.
Any ideas or insight as to how this fuel system works and how to improve it would be apreciated and greatly help me out.
Thanks


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## ny_fam (Apr 3, 2004)

*Re: 1.8 Intake manifold confusion? (Mr_Efficiency)*

Don't know for sure with out looking a the manifold you have, but it sounds like those little fingers sticking up are to help atomize the fuel. 
Sounds like you have some form of throttle body injection now, you'll need to check the rules to see whats allowable for changing the induction system.


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## WaterWheels (Aug 14, 2005)

The plate under the throttle body with the fingers and electrical commection is a heater. Seems you have a Mono-Jetronic or Mono-Motronic injection system. Yes, you can cut the fingers off flush with the bottom of the plate to aid a little in flow, but a very little. You can also machine a flat plate to replace the heater one like I did some years ago. The reason for the heated fingers is cold running and the heater element shuts off once the engine is warm anyway.
I know of no larger single point injection throttle body made by VW. There are some from performance aftermarket companies but if they would fit, I can't say? I can tell you that the fuel pressure can be adjusted to a small degree. It requires a thin shim (washer in this case) placed above or under the spring in the regulator. I used ones made of stainless steel to avoid rust and raised the pressure a few psi. This was done due to the installation of a camshaft, some mild port work and header.


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## ABA Scirocco (May 30, 2001)

*Re: 1.8 Intake manifold confusion? (Mr_Efficiency)*

Sounds like you've got the 1.8L Mk3 engine. That particular engine with it's mono-motronic throttle body injection is peculiar to Canada, they didn't get it in the U.S. as a result, there are very few people using it for racing. So unfortunately, I don't think you're going to get a lot of help with this.
Rather than tweaking you current system, would your rules allow you to replace the throttle body unit with a carb? If so, that might be better way to go. That particular intake manifold is very reminiscent of some earlier VW carb manifolds, it would be a simple matter to make an adapter plate to fit a carb to it.


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## Mr_Efficiency (May 7, 2008)

Thanks for the help guys.
Yes it is the odd ball Canadian 1.8, I'm having a hard time finding anything on it.
If that thing inside the intake manifold is just a heater then I am definatly removing it. This car only ever runs from april to october so cold starts are a non issue. 
And thanks for the fuel pressure tip, I know exactly what you mean. I have had a few regulators apart before, I'm just trying to be carefull with this vw stuff, they seem to do everything a little diffrently than I'm used to.
My rules do allow me to swap to a carb, but I know nothing of carbs and feel a lot more comfortable with fuel injection. Plus IMO fuel injection makes more power.
I used to run a 12valve prelude with dual carbs that were proffessionally tuned. It was the only carbed car out there that could give an injected car a run for its money. Then I switched it to injected and walked everything. So now I swear by injection.
Also thanks for putting a name to the injection system for me. I hear a lot of talk about digi2 and motronic etc... and I had no idea what one I have. Now that I know maybe I can find something on it.
Thanks guys
Edit: Why would vw put a heater in the intake manifold if the exhaust is right below it. Wont it get hot enough onits own? doesn't really make sence.


_Modified by Mr_Efficiency at 11:30 AM 1-17-2010_


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## ABA Scirocco (May 30, 2001)

*Re: (Mr_Efficiency)*


_Quote, originally posted by *Mr_Efficiency* »_
Edit: Why would vw put a heater in the intake manifold if the exhaust is right below it. Wont it get hot enough onits own? doesn't really make sence.


The only reason I can think of is to reduce emissions during warm up.


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## karl_1052 (Feb 10, 2008)

*Re: (ABA Scirocco)*

What are the rules in regards to the head/injection system?
You could always swap on a Digifant or CIS injection system, or manifold and run a standalone EFO system.


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## superl8 (Dec 31, 2002)

*Re: (karl_1052)*

You've got VWs uber econo engine management on that thing. 1.8 with Monomotronic . do rules allow 2L ? I had my golf CL's (which sounds like what youv've got) 1.8 swapped for a 2L which is port injected and has chip tuning available. There are also some decent stock exhaust options to make a little more power as well. If you must stay with the 1.8 you can put the later head (Crossflow) and engine management on it. Any 8v hydro cam will work as well - crossflow or counterflow. Kind of a heavy car for a small engine... Mk2 or 1 would be lighter and faster with a 1.8.


_Modified by superl8 at 8:48 AM 1-19-2010_


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## Mr_Efficiency (May 7, 2008)

I can run any stock vw head/ injection system as long as no modification is required to bolt it all together.
I had a fox with CIS-E and it was nothing but a nightmare I'd rather stay clear of that system. I know nothing about it and it never worked right and caused nothing but problems in my hands, lol
Weight is no issue, no matter what car its in with this engine the car must be 2200 pounds. Mine is 2230 with driver and 70 pounds of lead. Plus IMO the mk3 looks better and is way easier to find parts for.



_Modified by Mr_Efficiency at 5:08 PM 1-19-2010_


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## WaterWheels (Aug 14, 2005)

*Re: (Mr_Efficiency)*


_Quote, originally posted by *Mr_Efficiency* »_I can run any stock vw head/ injection system as long as no modification is required to bolt it all together.

This might be a good option depending on the exact definition of "no modification is required". Although I made some good power with Mono-Jetronic systems, the heads have the smaller valve combination and the system does have a limit. If you can switch to a large valve head and different injection system you will be able to build better on it. So clear up the above so nobody gives you bad poop.


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## Mr_Efficiency (May 7, 2008)

I casn pretty much run any vw injection that will bolt up to the head. 
No modification means I cant run it if I have to cut and weld to make it work.
Could you tell me a little bit about the Mono-Jetronic system? What cars it came on in what years, what its basis is? 
I dont know the vw injection systems.
Is this Mono-jettronic multiport FI with a regular MAP (or MAF) sensor and throttle body like every other car?


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## ABA Scirocco (May 30, 2001)

*Re: (Mr_Efficiency)*

The mono-motronic injection is found in Canadian MK3s with 1.8L engines. It's a single point throttle body fuel injection system. It is VW's only single point injection system, all other VW systems are multi point. This creates a problem if you want to install another system as the MK3 1.8L heads do NOT have any accommodation for injectors at the port. However, other VW heads do bolt up to the MK3 engine so if you wanted to change to a multipoint injection system, you could install an MK2 head.


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## Mr_Efficiency (May 7, 2008)

That sux.
I was just looking at the motronic injection and apparently it has 2 injection outputs at the ECU so I could pin into it and run a MPFI system having injectors 1,3 and 2,4 fire simultaneously. Then I could run any MPFI manifold and throtle body to make it work.
But now you've just sunk that ship cause I'm pretty commited to this head. So I guess I'll stick with what i have.
Its not like the car needs desperate help for power. Its one of the fastest things out there in the division. Just needs a little extra "omph" in the top end to bring the car to the front a little more often.
If you see my other thread I think I have that issue solved, lol








Thanks for the help, the website in you sig have been a great help as well.


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## WaterWheels (Aug 14, 2005)

Really there were two single point systems. The original was the Mono-Jetronic and like all Jetronic systems the ignition was seperate from the fueling. These were maybe only produced in Europe and used for about 5 years. The later version is the Mono-Motronic and as with the Jetronic system it follows all Motronic systems in that the ignition is also within the ECU. I used the Jetronic for a few years and was able to make some fair power with it. Cylinder head mild porting, compression raisied, intake manifold port matching and cleaning, good exhaust, increased fuel pressure, ignition curve modifying, mild camshaft, etc. all work to help the SPI system just like the MPI.
The Mono-Motronic was used here in Europe for many years from 1.4L - 1.8L engines. If you need some parts look around in Ebay Germany and United Kingdom.


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## ABA Scirocco (May 30, 2001)

*Re: (WaterWheels)*

Interesting, I'd never heard of mono-jetronic, I'm guessing perhaps it was never used in any North American models.


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## WaterWheels (Aug 14, 2005)

No, I don't believe it was ever used in North America. I thought maybe Canada as they did get some version of engines the US didn"t get, but maybe not there either. An Internet search should get you some detailed info if you interested and a common engine code in Europe that used it was RP.


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