markzb

Hi everyone!

This is my first post here, and my first Porsche Turbo (97 993 tt). What a car!

I would be grateful if anyone here can help me with a few questions I have.

1. The intercooler hoses are rather frayed on the turbo side. Someone here suggested that you should go for a "hard pipe" kit.

This seems like a good idea to me! I am thinking of going for this option, based on the fact that it will be cheaper to replace the short ends of this hard pipe kit should the need arise versus a replacement Porsche pipe each time. What say you guys? Any opinions?

Also..what do you think of removing part of the engine shroud around the area that the intercooler hose passes thru? On my car, the shroud tends to make it difficult to install the clamp on the intercooler hose, which I think is partly the reason why the hose gets chewed up. Any opinions on just "cutting" back the "horned" section of the shroud the hose passes thru?

2. How do I adjust the waste gates? I want to make sure that they are set to factory specs. How do we do so? I have a "hand pressure/vacuum pump with compound gauge" tool. Would this be good enough? Appreciate if someone can let me know what the procedure to adjust them is.

3. On the dahboard, we can observe thru the digital display the boost pressure. If I was accelerating hard from standstill, what should the maximum reading be? Pardon my ignorance here... I am a newbie....But I gather that if you dont get enough boost reading here...something needs looking into. So...on a healthy car...what boost reading should I get and at what RPM generally?

4. How do I determine if the turbos are working well. They are not smoking and the engine runs well. Since the two turbos seem to me to "common" in the intercooler, how would we know if one turbo isnt performing so well? Or if we have a slight leak somewhere on the pressure side?

How and where and what gauges can we hook up ( making all the necessary fittings as required) to ascertain that both compressors are pressurising correctly?


Thank you muchly for reading this!




mark

vrus

Hey Mark,

Congrats a great car!! Post some pics for us to see if you can.

1) Hard pipe kit is definitely a good idea. Once you have torn up 2 of the stock hoses you have pretty much paid for the hard pipe kit. Get some T-type clamps or breeze constant torque clamps also. The stock clamps are garbage. The ridges on them is what helps to cut away at the hose.

2) Not sure about this. I have seen someone attempt this before but I dont remember the procedure.

3) Maximum STOCK boost on a 993TT (non S-Model) is 0.8Bar for a brief moment, and then it should scale back to 0.7BAR. On cars with opened up exhausts (muffler bypasses or race cats), it holds 0.8BAR constantly and may even spike higher than that. The digital display is not very accurate and wont display anything over 0.8BAR so you wont know if you are overboosting.

In 3rd gear, 0.8BAR is usually reached by 4,500RPM or thereabouts (from what I remember when my car was stock)

4) Checking the turbos is a good thing to do whenever you get an opportunity. To see if your turbos are ok:

- Does your car reach 0.8BAR in 4th gear at full throttle? It should.

- Remove the Intake pipes on the turbos and wiggle the shaft of the turbine with your fingers. There should be no play in the shaft. If there is play, the turbo needs to be repaired as it will eventually break apart inside.

- If you see large amounts of oil come out you may have a bypass problem. There should be some oil in there, but large quantities are indicative of a problem.

- Remove your intercooler and lay it on the ground tilting it to one side. A little oil should come out of the pipe. Again, if large quantities of oil comes out, you have a bypass problem in one or both of your turbos.

Hope some of this helps...

ca993twin

Well, I'm no expert, but here goes anyway:

1. Turbo hoses, especially the uprated ones with the orange ends, tend to last a very long time, under normal operating conditions. It is recommended that you use a "Breeze" clamp at the intercooler end to prevent "blow-offs" and mangling the hose end. Hard pipe kits seem kind of extreme to me... but I'm a doofus.

2. I have no idea.

3. The digital boost gauge "computes" the boost by reading some other factors... it does not read boost directly. It can register a maximum of 0.8 BAR. You should see that reading above 3000 RPM at full throttle. !st and 2nd gear go by so fast, you probably can't get a good reading. You might try an uphill grade on the freeway in third gear, and you should see 0.8 BAR. If you never see higher than 0.5 BAR, you are in "limp" mode, and the car needs some attention. I have a mechanical boost gauge in addition to the digital, and find that the digital seems quite accurate enough.

4. If there is no smoke, very little oil in the intercooler, and you can get 0.8 BAR, your turbos are fine. If you cool them after driving, they can last 75,000+ miles before needing a rebuild. My car with 64,000 miles is still doing great, but I'm eagerly awaiting the turbo failure, so I can upgrade a bit.

Enjoy your car and enjoy this forum. Welcome.

Kevin

Do not bother messing with the wastegate adjustment until you are ready for an upgrade... You need to have a dial indicator to measure the travel at a set point.. You also need a very good accurate gauge and regulator to set the travel.. For most applications (stock) your okay... Unless, someone has be playing with it..

The easiest way to check for turbo damage is to pull off the intake boot, not the outlet boot (intercooler side).. and see if there is oil in the intake tract... Oil means seal damage/wear...

Forgive me Vrus.... do not wiggle the shaft for play.. the correct way to find out bearing wear is to dial indicate through the oil drain hole and locate on the actual turbine wheel shaft... Then you push away (up) with one hand on the quill (compressor end) and the other hand on the turbine wheel (hot side)... Most people will grab the quil and move it up and down, this will wreck you small turbo, you are preloading the shaft at a servere angle. You can break a sealing ring or break the thrust assy.. the worst would be a bent shaft...

K16-K24's rarely fail due to bearing wear!!! This means that we have seal issues, and this failure rate is due to heat... Can we say "hot shutdowns"... Now in the examination of the inlet boot/compressor side of the turbo, if you see radial rubbing or scratches around the bore.. You have bearing failure... so with that said... Look for oil, no oil means, turbo's are "okay"

markzb

Hi Guys

Many thanks for your replies. They are much appreciated!

Where do I hook up a presure gauge to to determine what the boost is?

Kevin, I think the wastegate adjustment was mucked around with. I have a dial gauge and stand, and am very prepared to buy whatever pressure gauges etc to do the job right.

Could you please, if possible, tell me how to set the wastegates to standard specs?

Many thanks

mark

Kevin

Mark;

Please humor me and measure in "mm" your wastegate adjustments. Measure from the end of the threaded rod to the outer edge of the jamb nut closest to the actuator pot.. I will tell you whats up..

markzb

Hi Kevin

Thanks. I will get back to you next week when I have removed the bumper and mufflers. But from memory, it looked something like 10mm or so.

Also, I live in Malaysia, and its very difficult for me to get advise from fellow colleagues in the trade here, as there isnt quite the spirit of cooperation amongst workshops that seems to be so apparent in the states. There are so so few turbos here as well.

I have tried emailing some companies to try and get a set of workshop manuals for this car, I only have up to 964, but no one even replies to my emails.

I am just trying to verify that everything is fixed right in the car and you guys are all I have!

Many thanks and get back to you next week.

regards

mark

markzb

Hi everyone

Looking thru the 993 forum, there was mention that there is a "pdf on cd " version of the shop manual for 993 cars.

Does anyone know if there is a pdf on cd manual for 993 tt cars? If so...where can I buy one? Any leads?

Cheers

mark

markzb

Hi Kevin,

Sorry for the delay. I just got the car back in. Ok Kevin..heres hoping you can help me.!!!!

I have removed the clips and I have measured the distance from the end of the rod (rearmost of car) to the front outer surface of the front lock nut ( front most of car).

The left side is 31.3mm and the right is 30.5. The adjustment was tampered with out of ignorance when removing the turbo's. The wastegate was thought to have required removal and the settings of the locknuts was not cared for.

I really hope you can tell me how to set it back to the correct setting.

many thanks

mark

Kevin

Mark

The measurements that you have provided are very close to a stock setting.. They will range from 29.50mm - 32.50mm. Again these are very close to stock, if it was me I'd jack them up 3mm.. if you have a freeflow exhaust.

Bill S.

The correct way to set the wastegates is to be sure the pushrod lifts 4 +/- 0.5 mm when applying exactly 0.5 bar of pressure. You need to securely mount the dial gauge to do this. Not many people have the setup/equipment to do this correctly.

markzb

Hi guys

Kevin...many thanks for those measurements! Much appreciated.

Bill, when you say the pushrod "lifts", have I interpreted you correctly to mean that we want the pushrod to extend rearward a distance of 4mm with 0.5bar of pressure.

I ask just to make sure I am not confusing this with the amount of "lift" of the wastegate of its seat.

I do hope I can ask another question as I have never driven one of these babies apart from this one!

I have set the turbo's wastegates as you have suggested Kevin. I have removed the rear exhaust pipes and can see that both turbines can spin by hand. If I briefly start the car for say 3 seconds without touching the accelerator pedal and then shut off and observe turbines, I would say that they both spin for about 4 to 6 seconds and then stop.

I bought a good compound gauge and I installed it between the throttle body and the solenoid valve that feeds both the intake manifold and the wastegates ( boost control valve?).

When I drive the car, my passenger observes that I can get 0.8 bar of boost quite easily.

My concern is two things..... one is that the dashboard digital boost gauge seems very sluggish and shows only 0.2 to 0.3 when I feel the boost kicking in whilst my mechanical gauge seems to show generally higher and faster response in its readings.

More importantly, the car seems to feel as though its really "pulling" only when I get the revs up towards 4000 RPM.

The car is I think a 1996 model, and the right turbo has the part number 993 123 01451 if thats any help id'ing it.

My question is, is it normal that the car feels like the turbos are only really coming on strongly at around 4000 RPM, or should they be coming on earlier?

Turbo lag, or you have to keep her fairly well revved in your driving technique?

Or do I have a problem that you can suggest I look at?

Many thanks guys.

mark

Kevin

As Bill has mentioned setting up the wastegates in his description.. This is used just to "sync" the two turbochargers together, similar to when we adjust the camshaft timing.. However, the stock setting is far to slugish for my taste and most others... Yes, you are measuring the movement of the actuator arm rearward. A dial indicator will track your movement. You need a very good regulatorand gauge that will read small increments...

When you say that you have adjusted them like I said, did you "tighten them up" 3mm? This means that you'd have to turn the jam nuts 3 turns clockwise... The stock gauge is sluggish, I'd dump it in a second, and mount a gauge where your clock is... Many have just reinstalled the clock behind the gauge cluster, hidden away, still connected to the wire harness.. Which gives this WARNING, disconnect your battery before you unplug your clock! If not you will get a CEL/Airbag warning light... Move the clock, then after the harness is connected, reconnect your battery..

Personally, I think that your car is running close to stock specs.. If you have low octane fuel your timing and boost CAN be pulled by the ECU.. thus giving you a "slugish" feel.. Sounds like a time to upgrade... you are on a slippery slope, being bitten by the "power bug"

Another note: To adjust your wastegates to the proper sync setting or starting point, one will have to spend about $300.00 minimum to buy the correct tools and gauges.. If one skimps and puts unregulated air or too high of an air pressure you will blow the diaphram in the actuator... The new actuator is $200.00 my cost.. And I have seen quite a few failed ones..

So with all of this, your settings should be 34.3mm and 33.5mm. You can stretch it to 5mm, however, you better watch your AFR's at this level... you will be seeing 1 bar boost... If my instructions about the adjustment are not clear, I can post some pictures on a stock actuator rod and then an adjusted rod...

Jean

Kevin, to some of us (or to me at least) your explanations sounded very, very, interesting but not sure we understand it correctly. If you have some time, it would be very helpful if you could post some pictures to show us what you mean..

Thank you.
Jean

TB993tt

Are you suggesting that you can increase the power output by manually adjusting the wastegates to give 1bar boost without touching the ECU