1.6L N/A Rebuild with turbo upgrade Help???

Ferrari692 · Post by **Ferrari692** » Thu Mar 20, 2008 2:55 pm

I am about to start rebuilding my 1984 rabbit that has a 1.6L diesel. I have read up on turboing it but I still have some questions that I can't find answers to. I would want to be able to hit 20-25 lbs max boost. I would appreciate any thoughts. Thanks for your time.

1. Are the 1.6 turbo diesel valves different and should I use those instead of the N/A due to increased heat?

2. Should I get the 1.6 turbo oil pan (I heard somewhere that it is bigger) or should I just tap mine instead?

3. Do I need to spend a ton of money on ARP bolts($135) or will new replacement ones work?

4. I have a turbo diesel fuel injector pump but still have the 135bar N/A injectors is this bad and should I upgrade to the 155bar turbo ones?

5. Which size oil pump should I use when turboing?

6. What pistons should I use stock or turbo and what is the difference?

82vdub · Post by **82vdub** » Thu Mar 20, 2008 3:40 pm

I think others have posted that several people on another forum have tried propane injection and raising boost pressures with dramatic failure to the engine. I guess the weak point is the head bolts, so you will only get so much boost out of it before it will fail. I think I will let others post these results if they read this post.

I think some of your questions can be best answered with the answer to the question above. I would like to comment that if you're going to take a motor that had 10PSI boost and double that or 2.5x it's original boost, $135 for different bolts is only going to be the starting place, not question whether it should be done. Serious boost (HP) requires serious money, or you'll find the weak spot pretty quickly.

audios · Post by **audios** » Thu Mar 20, 2008 8:56 pm

I also will be trying to do something similar.....what boost levels and HP can you achieve with the stock injectors, fuel pump, heabolts etc?

Ferrari692 · Post by **Ferrari692** » Fri Mar 21, 2008 11:10 am

I was under the impression that 20lbs of boost was easier/safer on a diesel than on a gas engine. If I am wrong what kind of boost should I be looking to achieve? Obviously I would not drive it with high boost all the time because I do want this car to last.

woodrat · Post by **woodrat** » Fri Mar 21, 2008 11:35 am

I would just go ahead and spend the dough for the better head bolts. $135 is pocket change compared to rebuilding your engine later.

the cummins engine in my truck can take up near 50 pounds of boost, but only with special head treatment and way better bolts or even studs.

Ferrari692 · Post by **Ferrari692** » Fri Mar 21, 2008 12:15 pm

Alright so I will definately spend the money for the arp head bolts, but does anyone have any info about the other 5 questions?

1. Are the 1.6 turbo diesel valves different and should I use those instead of the N/A due to increased heat?

2. Should I get the 1.6 turbo oil pan (I heard somewhere that it is bigger) or should I just tap mine instead?

3. I have a turbo diesel fuel injector pump but still have the 135bar N/A injectors is this bad and should I upgrade to the 155bar turbo ones?

4. Which size oil pump should I use when turboing?

5. What pistons should I use stock or turbo and what is the difference?

woodrat · Post by **woodrat** » Fri Mar 21, 2008 1:21 pm

Ferrari692 wrote:Alright so I will definately spend the money for the arp head bolts, but does anyone have any info about the other 5 questions?

1. Are the 1.6 turbo diesel valves different and should I use those instead of the N/A due to increased heat?

from what I've read, yes, the turbo valves are sodium filled for cooling.

Ferrari692 wrote: 2. Should I get the 1.6 turbo oil pan (I heard somewhere that it is bigger) or should I just tap mine instead?

The Bentley does not show the turbo engine as having a higher oil capacity.

Ferrari692 wrote: 3. I have a turbo diesel fuel injector pump but still have the 135bar N/A injectors is this bad and should I upgrade to the 155bar turbo ones?

Injector nozzles are about $10 each, plus some time to clean, lap and rebuild the injectors. I would go for the correct injector set ups, especially if you are considering higher than stock boost numbers.

Ferrari692 wrote: 4. Which size oil pump should I use when turboing?

don't know about that one.

Ferrari692 wrote: 5. What pistons should I use stock or turbo and what is the difference?

Also don't know about that one. I do know the turbo has cooling nozzles for the pistons but I'm not sure where exactly those live.

I'm sure that smarter people than I will weigh in on this.

ahistand · Post by **ahistand** » Sat Mar 22, 2008 7:42 pm

1. Are the 1.6 turbo diesel valves different and should I use those instead of the N/A due to increased heat?

The turbo valves used to be different. Several parts suppliers I have personally talked to say that today's valves are made the same; there is no difference between the NA and Turbo valves produced now. Your best best to confirm this is to check and compare part numbers for both. The intake valve is pretty much a non-issue. But the exhaust valve is the one to be concerned with.

2. Should I get the 1.6 turbo oil pan (I heard somewhere that it is bigger) or should I just tap mine instead?

It doesn't show to be bigger. Just tap yours. It should hold 4.8 quarts.

3. Do I need to spend a ton of money on ARP bolts($135) or will new replacement ones work?

I ditto what the above posters say about this.

4. I have a turbo diesel fuel injector pump but still have the 135bar N/A injectors is this bad and should I upgrade to the 155bar turbo ones?

The higher bar injectors for the TD motors is to help overcome higher combustion pressures to make sure the nozzles do not inadvertently open too soon. There was discussion recently about this, if I find it I can post it for you. You should use the 155 bar injectors, but you wouldnt be the first if you used NA injectors. Part of the reason TD motors require more advance is due to the higher opening pressures at the nozzle.

5. Which size oil pump should I use when turboing?

You should use the later style 36mm pump. But that is a good idea for any VW diesel, in my opinion.

6. What pistons should I use stock or turbo and what is the difference?

The turbo pistons have a cutout on the skirt to clear the oil squirters, and have a coating on them, probably a heat resistant coating of some sort. Some have said that the turbo pistons have a stronger top compression ring land, therby allowing higher internal combustion pressures. Personally I see no difference between the NA top ring groove and the Turbo one. The actual piston dimensions are the same. Back in the '80s according to some literature there may have been a alloy difference in the turbo pistons as well to overcome higher heat.

If you have no oil squirters in your block, then sending the pistons out to be heat resistant coated (ceramic) and anti friction coated on the skirts is probably a good place to start. There's no hard evidence to suggest that this is a adequate substitute for oil squirters, but it has been done.

Hope that helps.

Ferrari692 · Post by **Ferrari692** » Sat Mar 22, 2008 8:43 pm

Thanks to everyone for all the helpful information!

crankpot · Post by **crankpot** » Tue Mar 25, 2008 2:02 pm

the turbo block has piston oil sqirters, hence the need for a bigger oil pump. Low boosts are ok with stock pistons and pump.

Bob