Thanks Magnus, the car isn't fitted with a lamda other than the one that is there for the AFR gauge so I don't know if it would throw the ECU off.

Yes the car was mapped on the rollers (see post #73) and agreed it would need remapping if the injectors were changed but that's a good point that if they were limiting the performance it would have showed up.

Maybe the 300bhp max limit for 964 injectors is a red herring.

Exhaust diameters / 993 heat exchangers?
 

I'm having a bit of an exhaust re-think at the moment for a number of reasons one of them being the headers are sitting really low on one side and the car has some ground clearance issues. I am going to raise the rear ride height slightly but it still hangs pretty low.

I might also have a go at a new silencer to give me a few more options.

Final reason is that it's a pretty chilly place to be this time of year and I don't want a bit of cold to stop me using the car so may add a bit of simple heat back to the car. I must be getting soft in my old age!

The obvious headers / heat exchangers option is to use 993 ones with the flanges flipped and they have been proven to give very good power figures on some cars. I've borrowed a set to use as a template (cheers Jev) but having a measure the primary pipe internal dia is approx 1.5" and the outside diameter is approx 1.6".

http://i1089.photobucket.com/albums/...ps755ed69b.jpg

My current headers while being cheap and cheerful with poor merge collectors (of a sort) have 1.75" internal dia and approx 2" outside diameter. Headers shown below and Magnaflow silencer shown in link.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/584094-964-engine-rebuild-questions-4.html#post6406544

This is quite a size step down which bothers me a bit and if it won't allow the engine to breath properly then maybe it's not the way forward. I always thought as a rule of thumb that 1.625" was the 'norm' for a 964 and maybe 1.75" for 3.8 or tuned cars which is why I'm a little surprised that 993's have 1.5" bores.

I realise that changing the exhaust will require a remap but am clearly reluctant to do the work and make the change if I end up losing power/torque.

Can anyone who knows anything about exhausts offer any advice?


http://i1089.photobucket.com/albums/...ps647aba33.jpg

Hi Alex, wow, blast from the past! You well?

What with you, RobT (on Rennlist), me and a couple of other 964 rebuilds going on, there's a few of us in the SE with interesting projects underway (albeit yours is now a runner. Git!)

Re your headers, yes, the diameters you mention sound curious - wonder what the 993RS ran?

If you're feeling flush, then Joe @ BTB Exhausts makes absolutely top notch systems - my pal who's doing all the mapping work on my build swears by him as the only person of the many he's tried over the last 20yrs, that acknowledges and actually builds the primary and secondary lengths that Steve wants, to the tolerances he specifies. Not cheap, but....

He's a motorsport guy rather than a Porsche specialist, but I see he now also advertises in the Porsche press, so guessing he's now done done a number of systems.

Cheers
Spencer

Haha, yes all good thanks, hope life is treating you well too.

I've got a pic of a 993 cup set up (below) which is a similar setup as stock 993 but no heat required. I don't know what dia the pipes are and I find it quite interesting that people make quite a big deal about equal length headers when the 993 aren't even close.

I love the headers offered by s-car-go, washburn etc etc but my pockets really aren't that deep and although a lot of work has gone into them I do find them unnecessarily expensive, quality costs hey!

I guess one option is to hack mine up to try to reduce the depth they hang and add some burns collectors or buy some OBX or similar and chop them up.

The 993 heat exchangers seem a nice easy solution but I don't know if it will stifle the engine?http://forums.pelicanparts.com/uploa...1387144597.jpg

993 and 993RS has the same exhaust. The cup is also the same, but without the heater box around it.

I emailed 9 Meister about upgrading my 964 3.6 engine. Exhaust was waaay down on the priority list if it has a race cat or a cat bypass, that surprised me. On the other hand i have seen engines perform very well with stockish exhaust.

So Magnus, this it where i find you hanging around ;)

As someone mentioned earlier, the stock exhaust on a 3.6 measures ID=1.5"
Just swapping to a 1 5/8" has to make a difference. Going even larger....i don't know?

Are there any tests that show performance differences between stock, 1 5/8" & 1 7/8"?
Keeping the car as a daily driver & track-day car & slamming on a 1 7/8", i think might do more damage to the power band rather than good? Any thoughts on this?
Together with a light weight bottom end you will gain top end power, but lose torque.

So can we agree on a suitable size so i can start fabricating my headers :D



About issues with fuel, I agree with Magnus regarding swapping/not swapping the injectors. The ECU can only compensate for minor changes & in cases where you don't remap the ECU, you can just tweak the fuel pressure & install a wide band lambda / AFR-gauge as a very cheap safety device to keep track of your mixture.

Injectors 964 part # 911 606 120 01 have the following BOSCH # Bosch 0280150731 giving the following specs:

18.4/lb injectors and flow 194cc @ 3.0 bar, with a 21° spray angle for the cone characteristics. The connectors are EV1 type.

@3.8 bar (55.1 psi) = 300-320 hp



Also found this thread stating good info regarding the 964 injectors & fuel pressure, where Bill Verburg has a good answer with interesting facts :)

http://forums.pelicanparts.com/porsche-911-technical-forum/100792-964-injector-flow-rates.html

hope this helps :)

Injectors and headers
 

Thanks for the comments Magnus and Martensson - interesting read on the injectors. One thing that confuses me slightly is why run with stock 964 injectors that are near the edge of their performance envelope if you can run with injectors with a higher potential flow rate such as the 951 ones from a 944 turbo and run them at 80%?

I've done a lot of reading on the exhaust front. There are two good threads below that are well worth a read. It all seems to boil down to how deep your pockets are so if you are handy with a welder and have some time then fabricating your own is a really good option. I may have a go at drawing some up and see where it takes me........

Some of the fairly highly rated headers for middle money such as the George headers seem to only be available in mild steel which surprises me, as a minimum I would want stainless and for the sort of money the top end headers I would want titanium!

http://forums.pelicanparts.com/porsche-911-technical-forum/387066-georges-headers-vs-bursch.html

http://forums.pelicanparts.com/porsche-911-technical-forum/464151-what-headers-my-3-8-rsr-build.html

I used 993 HE,s with a double 2.5 in/ out muffler. then added small resonators in the outlets. I think made by magnaflow It used an internal x design which allowed easy inlet outlet position choices helpful when fitting to the body.
Homebuilt copy of Steve Timmons "happy crab" . Really modest cost perhaps $500 plus the used HEs I found on ebay at the time for maybe $300 . No idea of parts prices today but
Stock 3.6 from a 91 in a 1980 SC. In a car I did in about 1997

Seemed to work extremely well and fit the early 911 chassis. Noise wasn,t bad at all, ,no unusual resonance or complaints from sensitive passengers but no cats if it had to be smogged. Not required here in one that old
Heat was great with the 993 HEs .
I personally feel the biggest improvement over stock is achieved by muffler choice before it would be by header tube dia. increases /mods.
If you need cats then the stock cats work but muffler space in the early chassis then becomes hard to find. Without mufflers the stock cats are very load.
I think small tube 1 1/2" will support 100hp per L.
Note : When flipping the flanges on the pass side . There is one cyl .head stud which becomes difficult to get a nut / wrench on . I had a small exhaust leak at the port which was difficult to seal because the one bolt.

Header doodles
 

Hey John, mine was a 14" Magnaflow with 2.5" in/out too (see post #64). They work really well and cost peanuts as you say. Only difference with mine is instead of 993 h/e I went for a cheap set of 1/75" dia headers.

They are noisy but I made a pair of perforated inserts that fit in the tail pipe to quiet things down when needed.

I had a bit of spare time so was playing around with drawing some headers. They are reasonably equal length and made only using off the shelf bends. Bit rough and the 'S' bend on the middle pipes probably isn't ideal but wanted to keep it simple and stick to the 'off the shelf' philosophy. All of the bend rads are the same with 1.75" dia pipe and a 63.5mm centreline radius.

Don't really know where I'm going with this but maybe if they were tweaked to the right length with a pair of slip on merge collectors then maybe I could use the 993 h/e I have a s a jig to knock something up.

http://i1089.photobucket.com/albums/...psb4edea97.jpg

http://i1089.photobucket.com/albums/...psfcc8fd90.jpg

http://i1089.photobucket.com/albums/...psef889b55.jpg

I would just use the 993 HEs as is and you have good heat and good power.. I don,t worry too much about equal length on a street car. I somehow feel the 2 long pipes optimize two cylinders at low RPM and the two short ones optimize at the top end with the med pipes being optimum for mid rpms.
The averages end up being good over all rpms.
I used a 2.25 in out muffler as that was available off the shelf when I was looking.

Problem is the 993 h/e I have got with the flipped flanges are borrowed so I've been looking for a used set for a while but they're all silly money and would need modifying / flange flipping anyway. I've seen a couple of sets in the U.S. but shipping costs and import taxes make them pointless.

Heat is easy enough to add to most headers, just weld a box round them.

Thinking completely outside the box, can 996/997 headers be adapted to run on 964 engines?
I know the port is a different shape but could always cut off the flanges and weld on 964 flanges on something like this?

I only ask as when I was searching for h/e, this style of 997 GT3 Cup header popped up at sensible money!!!

http://forums.pelicanparts.com/uploa...1388232809.jpg

For heat you can always get a cheep petrol heater from China....

2KW Air Gasoline Heater 12V similar with Webasto park heater-in Mounts & Holder from Automobiles & Motorcycles on Aliexpress.com

I had no idea the 993 hes were bringing such money today I paid about $275 for the last pair I bought about 2006. I see them on ebay now for $800 plus. Steve Timmons shows them on his site at $650pr with modified flanges. Or I think $450 pr unmodified. Shipping to the UK can,t be that awful can it?

Alex, give my pal Brian Stageman ("911 Spares") a call on 07956 911999 (love that number...2 x references to Porsches and the Emergency tel number, haha)...by all means say I pointed you in his direction.

He strips 911's for parts down here in Kent, he's a great bloke with tonnes of parts from various vintages - I'm sure that if he doesn't already have various sets now, he probably will shortly (or may be able to source some for you)...doesn't remove the need to flip the flanges, but hey, another option for you.

Cheers
Spencer.

I have seen those and the Webasto heaters but never really felt comfortable with them in the frunk in a closed compartment with the fuel tank. Silly really but I'd be happier with a bean can welded round the exhaust. I also looked into electric heaters but they can't muster enough power and need more amps to be any real use.

Yep, a lot of parts like this are silly money now. Shipping to the UK is around $150 - 200 then add 25% for import tax + handling fee for the UK courier company (seriously) and before you know it you are easily over $1000 and for that much I'd rather make my own!!

Cheers Spencer, I bought a used 3.2 drive shaft/CV joint from him a few months ago. Maybe I'll give him a call. I have found a single RH 993 h/e in the UK but didn't want to press the button unless there was a LH around.

I understand, but almost every new diesel car (they take for ever to get warm) sold has them factory mounted now, at least in cold weather climates.

I have a small HE welded to my secondary pipes, the resulting heat is slightly warmer than ambient...
Electric suck even more.

The thing I can't get over is that diesel doesn't ignite like petrol and the tank isn't in the same compartment as the heater. The exhaust is 'free' heat however convoluted the path to make it usable is.

I made an electric heater using the elements from two 12v travel hairdriers. The result was luke warm air but not good enough to provide any useful heat.

You can get a diesel powered one and have small separate fuel tank. These things were common on old VWs, I have asked around with old mechanics and they say the same thing: unreliable, but safe.


But I think you only have one good option that suits you, the 993 HE. I have a pair waiting for me to get the time to install them on my 3.2. I think I paid €500 for them, flipped and ready.
For my 964 3.6 I might keep the stock exhaust, they seen good for at least 320hp anyway and there is better ways to spend the money, head work for example.

The modern heaters are widely used to safely and reliably heat commercial vehicles, ambulances etc as well as for marine applications. They have very fancy control systems to comply with all the safety regulations.

My 0.02, stick with the reputable brands.
Example the Eberspächer Airtronic M is compatible with gasoline....which means no need to install a separate diesel fuel tank!

I have a set of 993 Headers at home gathering dust if anyone is interested.

Hi Steven, thanks for your post - you have PM.

PM Replied :)

993 heat exchangers won in the end due to price and availability so I'll base my new exhaust project around those & if they don't work then I'll just have to have another rethink.

New exhaust here for anyone still awake!

http://forums.pelicanparts.com/porsche-911-technical-forum/795706-my-ti-exhaust-project.html#post7899631

This is a bit of a cross post as I know different people read this forum:

I don't know a great deal about exhaust design so I would appreciate a bit of advice from any of the knowledgeable folks on here who do SmileWavy

Because 993 heat exchangers exit facing each other I was planning on adding my 'X' pipe because it is already made and it is easier than manufacturing tubes crossing over each other. These then loop back round into the muffler where the left and right meet again internally.

My question is: Is this a bad design - Is it 'disruptive' to the pulses?

I don't want to go to the trouble and expense of making it if it is fundamentally floored. In an ideal world the 993 heat exchangers would face outwards and I could have a simple 'U' pipe into the muffler - I've even considered fitting the heat exchangers on the wrong way round but don't think they'll fit!

Exhaust design is like this:

http://i1089.photobucket.com/albums/...psd4e16aa9.jpg

http://i1089.photobucket.com/albums/...ps27b7a1d2.jpg

http://i1089.photobucket.com/albums/...ps1a1d90e4.jpg

993 heat exchangers fitted

http://i1089.photobucket.com/albums/...ps51801443.jpg

Silencer & pipework fabbed

http://i1089.photobucket.com/albums/...ps7f50b444.jpg

Bumper modified & tips made from Corvette exhaust

http://i1089.photobucket.com/albums/...ps139fe518.jpg

Can someone tell me how to get the harmonic balancer off? I ordered the extractor bolt from Baum, but it will take weeks to arrive. So I tried a 3-arm puller. I cranked it hard. It didn't work and actually bent the pulley. I assume the 10 bolts hold the balancer together and don't connect the balancer to the crank. So I left them there. Is this right?

It makes me wonder if the extractor bolt will do the job. And I can't get this Exxon Valdez engine apart w/o taking off the balancer because the A/C mount is behind it :mad:

I didn't use the porsche tool but tried bearing pullers and all sorts with no luck at all.

It is on a taper and mine had a small patch of corrosion on it so was completely seized.

I eventually removed it with a hex head bolt which I think was M14 x 1.5 and a piece of steel bar of smaller diameter behind it cut to the right length. This is pretty much the same as the Porsche tool which is essentially just a bolt with the threads turned off. Using this method you just tighten the bolt in and it pushes the pulley out.

One piece of advice I would say is to make sure you have enough of the M14 x 1.5 threads engaged as you don't want to strip these!

It was a very happy moment when it eventually went with a pop. Small victories and all that!!


If you need more detail, let me know.

Good luck!

Thanks so much. My engine was actually shipped over from England. The tinware is kaput - I'm sure I've corrosion going on here too. But, what are the 10 bolts on the pulley for? Do they need to be removed to get the balancer off?

Have you tried a hammer?

The tinware is often kaput, worst areas are usually the LH rear and side tray by the catalytic converter. It is not cheap to replace either unfortunately. I replaced mine with fibreglass so that it would not rot again.

I wouldn't undo or remove the bolts. Even if you take them all out you still won't be able to remove the pulley so your best bet is to persevere. If it is anything like mine then all you will do with a hammer is damage the pulley and they are $$$ to replace unless you find a good used one.

They are also a balanced unit (hence why they have a varying amount of holes drilled in them) and they vary from car to car.

The Porsche tool or a makeshift version using a bolt with a machined down shoulder or a piece of bar to tighten the bolt onto is the easiest and best way to get the job done.

If you put some steel bar into the bore/hole so that it sits a few threads in from the pulley then get an M14 x 1.5 bolt and tighten it down onto the bar then it should break the seal and the pulley should pop off. If it squeezes the bar and compresses it then you can always add a spacer or slightly longer length in there making sure you still have good thread engagement like I said before.

Does any of that make sense?

Just saw this over on the other channel:

Custom Crank Pulley Tool - Rennlist Discussion Forums

Nice and simple but as I said you can just use a bolt & small length of spacer bar.

Thanks. I wish I could machine a tool like that. My first thought was to fashion a bolt and an extension like you suggest but 14mm bolts are not easy to find. I had to modify a 3 arm puller to try to remove the balancer and that didn't work and bent the pulley, so I'm in no mood to fashion any tools.

How important is this balancer anyway? Clewett sells a serpentine system to replace the balancer. I assume it's only a pulley and not a balancer. Our host wants $1500 for the balancer. Which way to go?

Just order the bolt from the internet or ebay if there's nowhere close to you that sells them. Maybe metric bolts are harder to source in the US.

A lot has been written about the 964 harmonic balancer and crankshafts potentially snapping without them. A lot of pepole don't run them but personally I re-added it as I figured it wasn't worth the risk - Porsche didn't put it there just to look pretty!

$1500 is nuts, just put a wanted ad on Pelican. I just did a quick search and found two for around $100 each. That's how I found & bought mine.

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/777192-964-harmonic-balancer.html

http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/786117-fs-leftover-3-6-engine-conversion-parts-exhaust-pulleys-heat-crossovers.html

Hi Spencer,

I recently completed a total rebuild of my 3.6 motor out of my 1998 993. I used Wayne's book pretty much as my bible. For dimentional information not contained in Wayne's book, I relied on the Porsche Reference Guide data book for the 993. These little books are expensive (about $40), but essential for dimentional information.

In answer to your question about doing an update of Wayne's book to include the 3.6 motors, I sent Wayne an email with exactly that question. His answer was that he was not planning on editing the book for the 3.6 since these motors and the cars they came in were relatively low in number as compared to other 911's.

When I did my 993 at 110,000 miles, the studs looked pristine. Yours look to be far less than pristine. I would replace them. The cost to do it at this stage of disassembly is very low and so much easier to do then when one or more break with the motor in the car. Any stressed stud that has corrosion on it should be replaced since there is no way to determine the extent of intergranular corrosion and its impact on integrity. Just my humble opinion.

Well said,theres always one out there,if we didn't ask questions and make comments would forums work....not likely,some appear to not see it that way,as a wise man said,"there is no such thing as a dumb question only dumb people that don't ask them'',good luck with your project and well done I can tell you are on the right track.

Since my exhaust project has been completed the car now runs a bit rich - No real surprises as switching from 1.75" dia headers to stock 993 heat exchangers and completely different mufflers there was always going to be a knock on affect and the car was always going to require a remap.

So, I've got my car booked in to be have the map re-tweaked for the new exhaust and (in my mind) I've always planned on swapping out the injectors at the same time. My rationale for doing this is that last time the car was on his dyno in Dec 2011 it was making 308.2bhp and the stock 964 injectors max out at around 310bhp so they are operating at pretty much at their limit.

I've read countless threads about injector swaps and some people swap them for the 'big green' Bosch 0 280 155 968 injectors so armed with limited knowledge I was simply going to do this however the guy mapping my car said don't do that - they are way too big, almost twice as big as I need. Go for some stock 993 injectors or go for some BMW M3 injectors as the stock ECU only has 8-bit resolution on the injector outputs so you only want injectors in it that are big enough, not too big.

I know that 993 injectors was probably the sensible route to go but I've since bought some BMW M3 injectors and am about to get them cleaned and refurbed but was just wondering if anyone else here has run them?

I have a bigger motor than you Alex, but if you are re-mapping things you should be pretty safe unless you go crazy. Agree that the big greens are probably just too big. They are 440 cc/min @3 bar. I used Bosch 0 280 155 831 which are 300 cc/min @3 bar. Stock 993 injectors are 233 cc/min @3 bar.

The 300cc injectors are originally for Volvo apps, are a modern EV6 body with 4 hole cap. They should drop right in... but definitely will need to re-map.

http://forums.pelicanparts.com/uploa...1423141322.jpg

Hey preston_brown, thanks for the reply. I've read a couple of your posts when sifting through injector info about yours (3.9 race motor right?).

The injectors recommended were E36 M3 / E34 M5 injectors # 0 280 150 701
I've actually got # 0 280 150 792 also from E36 M3 Evo but should be about the same (245cc/min).

The advice I was given was that stock 964 injectors are around 200cc/min, so jumping up to 440cc/min (big green) is way too much because you're getting less than half of the accuracy. The E36 M3/E34 M5 injectors are around 250cc/min, so with 25% more flow available they won't top out until well beyond 350bhp, and very few 964s make that without considerable modification and expense. They also have the right conical spray pattern for my ports, unlike the 'twin-bent-spray' injectors designed for two intake ports of a four-valve head design.

I just find it interesting that there is not more people doing this or more info out there. I still can't find a comparison to compare all the injectors I considered.

0 280 150 731 (964)
0 280 150 786 (993)
0 280 150 701 (E36 M3)
0 280 150 792 (E36 M3 again)
0 280 155 968 (Big Green)
0 280 156 280 (Alternative to big greens)
and now
0 280 155 831 (Volvo)

Frustratingly the one I'm struggling to find all of the info about is the one that I've got which is the 0 280 150 792. I need to be 100% that it's ok before getting them refurbed. There's a lot of conflicting info out there! This one is quite good though:

Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table

I have 440 cc injectors in my 260 hp 3.2. Way to big, but it works.
For my 3.6 964 engine I just bought 6 of the Volvo injectors, I think they will be nice.