930 injection questions

[Guest]

Hi everyone,
New to the forum on here, I am looking to cut my teeth in the Porsche world and currently searching for a 930 turbo. Been into the VW scene for many years, quite handy with a spanner as a result.
I have a few questions, hopefully a suitably knowledgeable Guru on here can answer! Having driven a 930 and experienced the turbo lag, I would quite fancy converting to a more modern fuel injection setup with turbo control. Not doing this with the aim to increase power as such, just for driveability.

1) Does the 1984 930 use K-Jetronic or LE-Jetronic injection?
2) What intake manifold can I fit to a 3.3 engine to allow me to fit electronic injectors?
3) How much work is involved in converting 915 g/box to G50. I know G50 uses hydraulic clutch etc. Is it worth the hassle? Should I just get used to the 4-speed???
4) If I wanted to do something crazy like raise the CR on a 3.3 from 7.0:1 to 8.0:1 would I need to change the cylinder heads too? Has anyone tried this and kept the std heads? Which pistons are best to go for?

Thanks
Ray

 

[JBL930]

Hello Ray
I'm not a mechanic but i have had a few mods done on my 930 so i'll give you my thoughts, if turbo lag is your main concern then you can get rid of almost all of it and stiii keep the CIS system, the old 3LDZ turbo is junk, a more modern K27 varient or a ball bearing Garrett like i have will perform much much better, i would try this before going any further and see what you think. If you do go EFI then you can still use the original intake manifold, you could send it to 9m for porting etc, or you can modify a 3.2 carrera manifold, i don't know the answer to your gearbox question but i know that fitting a G50 is quite a lot of work, with regards to compression ratios and what pistons then you should call a specilist and discuss your requirements, it sounds like a lot of effort if your not interested in a power gain, like i said ealier though if it's just a reduction in lag then get shot of that old turbo, think about some after market headers too, you'll be amazed at the difference....

 

[Guest]

Hi,
Thanks for the reply. I was going to look into a Garrett replacement turbo as well, but I know there are a few other things to try too to improve lag and response. I will look into manifold/headers too!
Thanks

Ray

 

[nathan 1981 930 G50]

1. K-Jet

2. The car uses phenolic injector blocks. These can be swapped for aftermarket ones (usually they are aluminium) that accept electric fuel injectors. OR You can fit the 3.2 carrera manifold although it does need alot of work to make it right. As you stated you were not looking for more bhp the blocks will work fine for you.

3. I love my G50 box but it is a expensive mod to carry out. You would be better to buy a 964t than a 930. Maybe even find a '89 930 that has a G50/50 box, they only made these cars for one year so they are quite hard to find. I was actually looking for one.

4. The 3.4 pistons & cylinders could be used that are higher compression. This is what RUF did. They are Mahles so are of great quality.


You might also consider a non turbo 911 with a G50 box, maybe even a turbo look car as this has the brakes etc from a turbo. This car could then be turbo'd after reducing the CR.
Check out Protomotive in the states. You may even want to go twin turbo.
http://www.geocities.com/protomotive/

The possibilities are endless but I'm sure you will enjoy any 911 turbo original or not.

 

[Guest]

Hi Nathan,
If I switched to electronic injectors do you know which fuel rail I could use that would fit, or would I have to make one up? I am also looking into using a more modern turbo but these tend to be watercooled and I dont really want to fit an extra cooling system just for this.
You say RUF increased CR too, did they have to fit bigger intercoolers etc as well? I assume the 3.4 pistons/liners you said have a larger bore than the 3.3?
I will live with the 915 for now I guess and see how it goes, but improving the engine response would be a goal for me []

R

 

[nathan 1981 930 G50]

Not sure about the rails but I would think the guys that make the blocks would make the rails as well.

You could get a turbo like mine which is good for over 500bhp. Very near a direct replacement, no water cooling needed. You can get bigger too.
However, people do fit those types of turbos you are talking about without connecting the water cooling ports and they do survive. Track guys install a pump to pump oil through the water ports instead. You should be fine for trackdays and road use though without cooling.
I have a turbo timer built into my alarm to allow the turbo to cool down.

Yep, Ruf did their own IC and of course I would get a better IC before upping boost or CR.
Yes, they were bigger bore & fully finned unlike the 930.

You can keep using the 915 until it fails []
I take it you already have one installed ?

 

[sjd]

I found the best cure for turbo lag was a combination of a K27/11 turbo and direct route manifolds. With larger intercooler this gave about 400bhp and much easier to use than standard 300bhp with all the lag that comes with old turbo unit. I have taken mine to about 500bhp now (and had to uprate further the K27/11 to K27/29 hybrid to get there), so it is possible, but you will need to dig deep.

I currently have 4 speed box, but have fitted short ratio ring and pinion to give more useable road gearing (150mph max). Just about to go for G50 conversion. Choices are to get shortened gearbox from USA (US$10K+), or have the torsion tube modified, which requires rear coil-over suspension. With hydraulic clutch operation as well it is no 5 minute job. Suspension is going to cost £1500+, fitting the same money again, misc parts £500+ and the cost of the box itself. You can sell redundant parts to help with cost, but it is not going to be cheap.

 

[Guest]

Yeah 915 fitted.
I read in one of the 911 history books that they removed the fins on one side of the cylinders for some reason - maybe clearance? I am going to look seriously into changing pistons to bring up CR. I hear that BahnBrenner in the USA do injector inserts for the 16V Golf to convert K-Jet injectors to Bosch fat electronic type. Does anyone know what thread the inserts are on the 930 intake?

Some interesting stuff regarding the turbos. Nathan, what turbo are you running with?
SJD: When you upgraded to the K27/11 did you do any other mods (internals) to reach 400hp - except for the manifolds and IC you mention? What was the response like compared to the OEM turbo? Also, are you still using K-Jet system?

Also, my 930 didnt come with the optional LSD so will need to sort this also! []

 

[nathan 1981 930 G50]

The reason they did not fully fin them was because they were trying to balance the temperatures. Anyway, it didn't work.

I would go with Pat Williams injector blocks and rails.
http://www.patwilliamsracing.com/efimanifoldkit.htm

I am running a custom turbo built by Kevin in the usa. It is his K27HFS. The next size up which is too big for cars using the K-jet/CIS is known as the K27HF2 which is what you might want if going EFI.
http://www.imagineauto.com/turbos.htm

Both these companies are great engineers and have happy customers. Stephen Kaspar of Imagine Auto made his own injector blocks and fuel rails but I don't think he will sell them to anyone. I think they are only for cars that he converts to EFI at his shop.

 

[Guest]

Cheers Nathan, some excellent links there!
I take it that I have to fit a crank pulley trigger wheel to register engine speed (looks like PWR do one?). I have seen flywheels for the 915 gearbox with 60-2 teeth machined around the edge for a bellhousing-mounted sensor - but its not for the turbo 915 []

 

[sjd]

I am still runing CIS - good for 450bhp. To take beyond that I have used Andial fuel enrichment kit that cuts in at 0.8bar pressure. Alternative is to have the fuel head modified. We have montored the Andial on the rolling road and it does the job well to 1.2bar.

I first used the K27/11 with standard manifold and high performance exhaust. However, it really came into its own when I added the direct route manifolds. This cured the lag issues I had until then. Later I had 964 cams added with IC and we run 420bhp on Bob Watson rolling road. Only other internal was lightweight clutch kit. 20bhp was credited for the cams, thus my circa 400bhp figure. What I have found is that as the car has been tuned it gets progressively more sensitive to temperature changes - so all figures depend on how cold the air is.

Bigger K27/29 turbo upped power, but at cost of driveability. I can only describe it as violent at 4000rpm, so not the choice for all and I would not recommend for a daily driver.

 

[Guest]

When you say 'direct route manifolds' do you mean ones without heat exchangers? If this makes a big difference to turbo response then I'll definately try this. I think a turbo upgrade will go without question also.

I would also like to try electronic injection too if I can improve the economy as well, which is pretty rubbish as standard.

Once again, thanks for all your responses so far! Keep 'em coming!
[]

 

[sjd]

Direct route manifolds run direct to rear of car, so reduce exhaust length and ensure exhaust gases are hot as they hit turbo. You can get these both with and without heat exchangers. Mine have the exchangers.

You will need to save a lot of fuel to pay for the electronic ignition!

 

[nathan 1981 930 G50]

EFI is very expensive. I can never see myself doing it or having it done because of the difficulty doing it myself or the cost needed to pay someone. Colin Belton of Ninemeister does Motec conversions. These are great ECU's but the price is very high for a conversion.
I would thnk that PWR would fix you up with everything you need as would Colin. Another cheaper option would be GSF. They also could fix you up with parts. I personally would only like Colin, PWR or Imagine Auto.
http://goingsuperfast.com/EFI-930-Turbo.html
Maybe I am just a snob []

With the headers mine are as short as possible leading to the turbo. This is meant to give the quickest spool up time of the turbocharger.
Longer equal length headers will give more bhp at high rpm but at the cost of lag.
All headers with heat should rob some bhp from the engine. Probably only 2 or 3 bhp though. Who cares on the street, better than being cold.

I have a modified USA fuel head which flows more fuel than the stock euro one, modded or not.

 

[Guest]

The US metering head flows more than the Euro one? Thats odd considering that they usually have more stringent emissions laws at that time! Cool find though []

I am fortunate enough to be more than proficient at fitting an EFI kit myself. I have done many conversions on VW's in the past - a few of which were my own cars. I like the DTA systems, and with their turbo control mechanism (same theory as used on all modern turbos) they allow boost to come in very early. How much are companies charging to do the EFI conversion then? Once I have built a loom for myself then I will be able to replicate it if anyone else needed one and will be able to fit as well.

Also you say that the heat exchangers rob power. I thought it was just a box section around the pipes or is there more to it than that?

 

[nathan 1981 930 G50]

The USA head does not flow as well as the Euro one.
However my modded USA head flows better than a Euro one & even a modded Euro one.

The reason for the drop in power of headers with heat is that the headers will not be as hot as the ones without heater boxes. It is a very minimal loss of bhp. Unless you are racing you may as well have heat. When racing I guess it's nice to lose as much weight as possible, especially from the right end of the car.

Your EFI sounds interesting. Keep us posted. Who would do the tuning ?

 

[Guest]

I have a couple of contacts that I used to use for mapping. They dont have any prior experience of mapping Porsches, although it shouldnt make much difference. There is always Bob Watson's as well, he has a rolling road doesnt he?

 

[nathan 1981 930 G50]

Yes, he has a rolling road.

If that is where your going to go you would be best to go with an ECU that he can tune rather than one that you like.