930 tuning

Guest · Nov 28, 2007

Hi everyone,

I've had my 930 for around 2 years now and I'm starting to get the itch for more power. I believe it has had an engine rebuild in the last 30k so it's a sound base to start from. It's an 1982 3.3 beast and I've had it dyno'd at 306bhp (SUN dyno). The previous owner said that it has a K29 turbo (?), Carrera 3.2 heads, SC cams, 48mm ports, hydraulic cam chain tensioners, and an exhaust with heat exchangers deleted. It's not indicating 1 bar on the in-car guage so I'm not sure how much boost it's running...

Anyway, I've got a Kokeln Kl100 intercooler kit ready to go on and a wideband fuel-air set-up. My question to all you knowledgeable people out there is what I should be looking at doing next?? Should I be looking at fuel delivery, wastegate and/or ignition??

Thanks in advance - I would be grateful for any advice...

John Baker

sawood12 · Nov 28, 2007

A conversion from a single port wastegate to a dual port wastegate got me over 20bhp in my 944 at slighly lower than stock boost pressure, and with aftermarket chips and a boost hike a further 35bhp was released. In addition to the wastegate you'd need an external boost controller and ideally some aftermarket chips. If you wanted to increase boost you would also probably want to invest in some larger injectors. Boost now comes in earlier and with less of a step so is more controllable in the transition zone between off-boost and full-boost. I'd say boost control is definately where you should look. The stock Porsche single port wastegate is never an ideal peice of kit even when brand new and it deteriorates over time.

John_Ward · Nov 29, 2007

ORIGINAL: Treecare930

Hi everyone,

Anyway, I've got a Kokeln Kl100 intercooler kit ready to go on and a wideband fuel-air set-up. My question to all you knowledgeable people out there is what I should be looking at doing next?? Should I be looking at fuel delivery, wastegate and/or ignition??

Thanks in advance - I would be grateful for any advice...

John Baker

Take a look at the 911 Turbo Register section of this months Porsche Post and you'll find how Simon Dixon headed towards 500 bhp in his 930.

911addict · Nov 29, 2007

Be very careful which 'specialist' you use for any mod work. (As the Americans say, ask me how I know.)

JBL930 · Nov 30, 2007

[/quote]

Take a look at the 911 Turbo Register section of this months Porsche Post and you'll find how Simon Dixon headed towards 500 bhp in his 930.
[/quote]

Please can you post a link, i'd like to read that

JBL930 · Nov 30, 2007

ORIGINAL: Treecare930

Hi everyone,

I've had my 930 for around 2 years now and I'm starting to get the itch for more power. I believe it has had an engine rebuild in the last 30k so it's a sound base to start from. It's an 1982 3.3 beast and I've had it dyno'd at 306bhp (SUN dyno). The previous owner said that it has a K29 turbo (?), Carrera 3.2 heads, SC cams, 48mm ports, hydraulic cam chain tensioners, and an exhaust with heat exchangers deleted. It's not indicating 1 bar on the in-car guage so I'm not sure how much boost it's running...

Anyway, I've got a Kokeln Kl100 intercooler kit ready to go on and a wideband fuel-air set-up. My question to all you knowledgeable people out there is what I should be looking at doing next?? Should I be looking at fuel delivery, wastegate and/or ignition??

Thanks in advance - I would be grateful for any advice...

John Baker

Was the 306bhp at the wheels or crank? I'm assuming it's at the wheels otherwise you've got standard power.
With cams, porting, exhaust and a K29 it should be quite strong (if a bit laggy), can you post some pictures under the car so we can see your exhaust/headers and a pic of the turbo would also help with identifying what you have, what is your boost gauge indicating?

sjd · Nov 30, 2007

It is difficult to say what to do next with so many uncertainties of what mods you have now.

I think it is unlikely that a K29 will work well on a standard exhaust and is designed to run high boost levels so wodul not work well without substantial other mods. As JBL930 raises it will be useful to see what manifolds and exhaust you have. You should also verify the turbo you are running - a K29 is not a bolt on job... it does not line up like the K27 and has a wider neck on the outlet than a K27. Accordingly, the pipe from the turbo to the standard intercooler will have need to be changed. Perhaps you can see the serial number on the turbo?

You will need to get an aftermarket boost gauge and test what you have now - if the boost is down then the simple answer will be to fix that first before doing anything else.

IF you have the right parts and they are working well together then the new intercooler will help, but not be transformational on its own. I am not sure what you mean by wide band fuel-air...is the car running electronic fuel injection? (you mention 3.2 heads) - if so then that makes sense but adds a while heap of complication in working out what you have and next steps to take.

Happy to help, but a starting point needs to be established first.

regards
Simon (Dixon)

sjd · Nov 30, 2007

As a "post script", and by coincidence, I have been in contact with another member re the tuning of his 930, with a similar bag of parts. This also indicated low power without apparant reason. On inspection it seems the wastegate is completely shot.......

The moral of the story is that first thing is to check all the existing parts are in good shape before bolting on more mods....otherwise you risk throwing good money after bad. This check should include all the standard service items - spark plugs, ignition leads etc etc

Simon

JBL930 · Nov 30, 2007

Off topic sorry, Simon what boost are you running? And are you still on CIS? Can you post a link to the write up on the work you've had done to achieve near 500bhp, cheers. Or of course you can e-mail me, it's jon@kigi.co.uk

Guest · Nov 30, 2007

Post the link to me aswell - I couldn't find it either!!

Guest · Nov 30, 2007

Apparently my 930 has a 3.2 carrera head, but I have a mechanical fuel injection.
I'll take photos tomorrow and will post them up for you to have a look at. What the paperwork is telling me and what has actually been done could be two different things!

sjd · Nov 30, 2007

We have two threads here.

Treecare I look forward to seeing what you have here. The article John refers to is in this month's Porsche Post - I will see if I can scan and email if I can..

JBL - I will email the list.

regards Simon

sjd · Nov 30, 2007

Here is my note to JBL

Basic parts:-
Engine rebuild, 964 cams, Hayward and Scott direct manifolds, K27/29 turbo (with all custom pipework to the I/C), Fabspeed exhaust, Kokeln Intercooler (plus dump valve update), Greddy boost controller set at 1.2bar (rebuilt wastegate), Andial fuel enrichment kit (needed as CIS runs out of steam at 425 - 450bhp), powerflow airbox, aircon and air pump removed, magnecor leads, centreforce lightweight clutch kit, Patrick Motorpsort lightweight flywheel [looks simple when you list it out like this].

This produced 473bhp and 505llbs of torque on the G-Force rolling road (my brother ran his 2.5l Scooby alongside the Porsche and this produced a 250bhp figure that had been checked a month before on another road). The boost was falling off to 1.1 bar on the Porsche as it started to run hot.

In September I took it on a track day and we split one of the cylinder barrels!!. RUF spotted the 3.3 barrel as a weak link at circa 500bhp - lesson learned. The engine is in with Bob Watson now to have 98mm 3.4l barrels and 7.5CR pistons fitted. We are also having the cylinder heads and barrels "flame ringed" (we can then run 1.3bar subject to fueling), the inlet ports polished, full balance on the crank, rods, pistons etc and the crankcase gas flowed by machining cut outs in the back of the barrels. This is as much as I think I can do for a road car without ditching the CIS and distributer - anyway we are expecting to easily break the 500bhp barrier and I had more power than I could put down through 245's before latest upgrade.

The parts I have used are all based around a blend that I think works well together and come from experience gained over 10 years of working on the same car. I am sure there are other ways to approach this - for example US guys can get more, but they grind out the cylinderhead exhaust ports ... at the cost of torque numbers.

All this has been done on a fresh engine with all new valves etc put together by Bob Watson (shame he needs to do it all again.. for my bank manager!!)

Simon

JBL930 · Dec 1, 2007

Simon, thanks for the e-mail, sounds like you're having fun with your car! What possessed you to run 1.2bar though without doing any head mods, you must of known it was going to go bang! Also how on earth are you going to get enough fuel in there for a 3.4ltr engine running 1.3bar on CIS, surely the Andial thingy playing with the WUR isn't going to get enough juice in to support that, are you thinking 7th injector? I've had one on my car for a while with no issues apart from it running really rich, I'm told it isn't a good long term solution though due to the risk of uneven fuel distribution, I've disconnected mine now, I've got the IA fuel head/metering head and I'm about to fit an adjustable WUR to get the fuel right, I'm never going over 1.0bar though so I don't have as much fuel to find.
Good luck with it, would be good to see it in action when it's done

sjd · Dec 1, 2007

It was not the 1.2 bar that was the direct cause of the a problem - the fueling was fine and we did not melt anything. It was the actual barrel that split (one inch long slit down the side - the head to barrel seal was fine). The Andial has a 5 position setting. We were running it at setting 3 and the air fuel ratio was fine. When setting it up on the rolling road we tried position 5 to see what would happen and it completly over-fueled. So I am confident that we can get the fuel in to run 1.3 bar if we can set it up properly. NB I run a 100 octane mix to assist with avoiding detonation problems.

I can understand you not wanting to run more than 1 bar - in which case a K27 will be optimal - the K29 would otherwise be "wasted".

NB I recently went to a Skyline rolling road day and saw a road car runing 2.5bar and producing 900bhp at the wheels...not sure it will last too long though!!

regards Simon

JBL930 · Dec 1, 2007

Those Jap motors can take some serious boost, the water-cooling helps too. I'm surprised you have so much fuel to play with, the Andial unit just manipulates the WUR to lower fuel pressure on boost right? I was under the impression (uneducated) that this was old hat now and the best way to go was with an adjustable WUR and a RPM triggered solenoid switch to bring on the enrichment through the WUR, but even then you were going to struggle to get enough fuel in for the high 400's and would be definitely short of fuel for a real 500bhp?
I've fitted a K27 HighFlow S, there is a blurb on this link, it's halfway down the page http://www.imagineauto.com/turbos.htm
I'm going to stick with 1.0bar because I don't want to snap my head bolts, I'll be taking mine to a rolling road soon to see where I am power wise, I'll not use Bob's dyno again because it doesn't give you a print out of the fuel curve which is what I'll be most interested to see. Good luck with your project

Guest · Dec 2, 2007

Hello Simon,

I had my 930 checked out by Porschemode in Bristol yesterday. They confirmed that I actually have a K27 (Used to be a K29, but when I bought it the dealer must have taken it off!!). It is not a high flow K27, the first 2 digits we were not able to see but it was completed with 13010597 9707006, if this is any help!
I have the original single wastegate on there also. It is wore out and will need to be changed - what do you recommend?
Already have a sports exhaust fitted with dual outlet.(1986)
I though about completing the following:-
New Kokeln air intercooler
New Kokeln turbo, or K27 High Flow S (which do yu recommend?)
Dump Valve?
A R-500 Digital Air/Fuel Wideband Ratio (measures if too lean or too rich)
Fuel Pressure Regulator - adjustable from Paragon Products
Booster Control
Change CDI ignition for MSD Unit & Blaster Coil
Obviously the spark plugs, HT leads etc will be changed.

Any advice would be greatly appreciated.
Regards

nathan 1981 930 G50 · Dec 2, 2007

Tree, you have a K27 7006, that is better than the stock K26 but the K27 HFS is better still. I got mine from www.imagineauto.com you cannot buy them here in the UK.

The Tial wastegate also from IA is what you need. I have one.

The Kokeln is a great IC. I have one too.

You could get a alloy Forge recirculation/bypass valve. do not fit a dump valve as you still have CIS. I want to get one of these. http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=0006&product=FMCL007P

I have an Innovate XD-16 kit. They can be calibrated for accuracy. Also from IA.

You have no use for a FPR. They are for EFI.

Do you really want boost control? You can just get a 0.8 & a 0.9bar spring with your wastegate and see what gives you just under 1bar for reliability.
If you do want adjustable I have the Blitz dual sbc. I am going to try and use it to help with launching at the strip. I have a 0.5bar spring in my tial WG.

The MSD is meant to be a good upgrade. Not essential but a good thing to do. Won't actually give you more bhp. It is NOT a substitute for going twin plug per cylinder.

I would stick with new stock plugs and leads. W3DPO plugs.

Let us see some pics of your exhaust and manifolds (headers).

sawood12 · Dec 2, 2007

The reason I suggested using a dual port wastegate is not necessarily for the ease of boost pressure control but more for near-elimination of lag. The problem with a single port wastegate that uses a spring is that even though you will have a spring rated for a specific boost pressure your wastegate will be opening prematurely. You cannot get away with this by using a spring as a spring is not an on/off device - there is a deflection associated with a force. A single port wastegate with a '1 bar spring' will be fully open at 1 bar manifold boost pressure, but it will crack open before you achive 1 bar hence increasing lag and loosing power. If you use a much stronger spring then you risk overboost. A dual port wastegate's second pressure signal will hold the wastegate postively closed until your maifold pressure has reached your intended pressure. As I said in my original post, by using a DPW at my stock max boost pressure I gained over 20bhp and turbo lag was massively improved. Not a massive BHP increase I grant you, but it probaly would be more with a 911 engine and at least you know you are getting the best out of your engine at any given boost pressure. I'd suggest it should be one of your first port of calls when tuning any turbocharged car.