My Carrera 3.2

[Peter M]

Fantastic summary of the differences between the later air cooled engines from the 3.2's onwards.  Well worth a look for the boffins:

964-993 Engine Tech Info Porsche Factory.pdf - Google Drive 

[Peter M]

Fuel Injector Sizing Confessional

I posted this review of my bumbling about with regard injector sizing in another thread that I've only just remembered.  Go to the last post dated 21/1/22 for sizing injectors for a 3.4 NA:

 

[Peter M]

Ever wondered what's inside a standard  Bosch air flow meter on a 3.2:

Now you know!

Actually its inside a Wurlitzer Side Man drum machine from 1959. One of the first drum machines. But similar technology to a Bosch AFM!

[OZ930]

3 hours ago, Peter M said:

Actually its inside a Wurlitzer Side Man drum machine from 1959. One of the first drum machines. But similar technology to a Bosch AFM!

Come on PeterM, it’s not an eye sight test !

and yes it does look like the electrics in a “classic” Porsche.

😁

[LeeM]

4 hours ago, OZ930 said:

 

and yes it does look like the electrics in a “classic” Porsche.

😁

Only less complicated and probably more reliable 

[Peter M]

Oh Lee,

Don't let old 911 wiring get you down!  Just be grateful you don't have a 928:

[LeeM]

3 hours ago, Peter M said:

Oh Lee,

Don't let old 911 wiring get you down!  Just be grateful you don't have a 928:

 Well aware of the 928 wiring 'simplicity' mate 👍 😁

[Peter M]

On 10/09/2019 at 18:30, Peter M said:

What's Extrudehoning the Intake Manifold and Bigger Throttle Body Worth?

7 Dynojet rwhp according to Steve Wong:

http://forums.pelicanparts.com/porsche-911-technical-forum/126005-3-2-intake-mods-pics-info-good-read.html

 

 

On 13/09/2019 at 19:21, Peter M said:

Bigger Throttle Body Worth It?

Appears to be but by how much I can't seem to find any one who knows for sure.  This appears to be the closest thread to knowing something factual....

http://forums.pelicanparts.com/porsche-911-technical-forum/1015032-3-2-throttle-body-question.html

However the pressure drop I measured in my data log (above) suggests there's a few hp's to be exploited.  

 

On 14/09/2019 at 12:04, Peter M said:

Larger Throttle Body

EFI Hardware in Victoria offer this service for $330.

https://www.efihardware.com/products/1724/enlarge-throttle-body-fly-by-wire

Time for some tech!

Does a larger throttle body on a 3.2 add power?  I've been pondering this for a while as you can see above.

Sure the larger butterfly gives more part throttle power for each degree of opening due to the larger area and therefore flow but does it add power at WOT or is the 3.2's airflow ultimately constrained by the intake manifold or the air filter?

When the mercurial Micky Dee ( @Mike D'Silva) mentioned he had a throttle body being enlarged by Steve Wong (911Chips.com - Porsche 911 Performance Engine Components), I thought this was a golden opportunity to find out by back to back testing.

Not having a dyno at hand or a standard 3.2 for that matter, I though I could do some ramp runs using my modified 3.2 to measure the change in acceleration times between two specific rpms, say 2,500 to 6,500 rpm using the data logging function in my Motec M130 ecu. (I don't have a wheel speed sensor configured to my ecu but can log engine rpm and the time it takes between these chosen rpm points).

I'll also measure the net difference between atmospheric air pressure and MAP at WOT at redline for both throttle bodies based on the premise that torque is directly related to intake manifold pressure when all else is kept constant.  Whilst change in acceleration times is a real world measure, I can't easily adjust climatic conditions unlike the MAP so there will have to be that caveat. Both measures however should give some solid evidence of the value of this modification.

Depending on what I find above, I may have to consider and test if the air cleaner/air box is becoming a more significant obstruction.  You will recall (!) from earlier testing that I found by placing a couple of large ports in the air filter lid, the airbox now flows as much as the not having a filter element and standard lid at all. (ie the MAP for both configurations were near enough the same.)  However keen Mezger students will recall that whilst Porsche continued to use the same AFM from the 3.2 to the 964, they enlarged the airbox along with the the intake manifold which suggests the 3.2 one was at its limits with the larger 3.6 engine.

 

How much can a 3.2 throttle body be enlarged?

Steve Wong suggests the bore can be enlarged from 63mm to 66mm or about a 10% increase in area.  Maxbore (maxbore.com/porsche.html) indicate an increase from 63 to 67.5mm.  I measured Mike's enlarged throttle body at 66.5mm.  In terms of flow, based on laminar flow and Poiseuille's Law, a bore increase of this order is equivalent to around 27% increase in flow!  However, let's not sweat the modelling numbers, lets just say the change is "significant".

Note how the boring exposes more of the vent port on the larger throttle body below.

 

The "spare" standard throttle body on the left I bought specifically to enlarge but because I couldn't find any real data, I couldn't justify the expense of boring at the time.  However, having a "loaner" will allow me to test the water for the cost of some postage. 

I'm also interested in assessing if the larger body makes the car unpleasantly sensitive to throttle, particularly small openings typically used around town. It's pretty sensitive/responsive even now! 

 

[Peter M]

Ramp runs?

(2) Road Tuning | Ramp Runs On The Road Or Track [FREE LESSON] - YouTube

 

[tomo]

1 hour ago, Peter M said:

Ramp runs?

(2) Road Tuning | Ramp Runs On The Road Or Track [FREE LESSON] - YouTube

 

That's certainly easier than sitting on the mudguard of the old Chev twisting the Dizzy till you got it just right .

[sus911]

I eagerly await!

Bog stock 3.2? I have one, well, sort of....

[Peter M]

Well, this has been a learning experience!

Initial Impressions

I installed the larger body without dropping too many washers and clamps down into the dark recesses of the engine bay.  The first drive was noteworthy for:

• I didn't notice any change in behaviour at part throttle.  I couldn't detect the promised "like punching the sport button on a modern car" feel promised by Steve Wongs advert: 911Chips.com - Porsche 911 Performance Engine Components .  It just felt it's normal smooth and creamy responsive self!
• At WOT above 6,000rpm it felt great!  Willing and revvy, I couldn't get enough of it.  On the way home I was constructing my "Want To Buy" advert to hopefully tease out an unwanted enlarged throttle body from an ex-3.2 owner's box of bits. 

If this was Pelican Forum, that would be the end of the "scientific" analysis and the above vague comments would be posted and repeated ad nauseam until it become folk law.

But this is PFA and we expect better.  Plus I promised you some ramp runs and solid data! 

 

Test Method 

I took a couple goes at this to come up with something that was achievable, reasonable safe, repeatable and minimised induced errors.  I adopted the following:

• Same road, same direction, no traffic, slight uphill rise to increase loading to better exaggerate any differences in engine performance
• Tried to keep reasonably consistent weather conditions
• Measure the acceleration time between 2,500rpm and 6,500rpm at WOT in 3rd gear. ie 61 to 158kph.  I don't have a speed sensor but can datalog rpm easily
• At a steady throttle at 2,000rpm in 3rd, approach a fixed point on the road, in my case a shallow causeway, at the fixed point go immediately to WOT and hold it flat until rpm reaches around 6,600 or 6,700rpm.  I found starting the acceleration early and ending late reduced driver induced errors too. 

 I was going to average a number of runs but found using the above method gave very consistent results.  However I noted other data that could be used to interpret the results such as ambient temperature and pressure, inlet manifold pressure, cylinder head temperature and Lambda.

I was also going to do screenshots of each run but you really need to use the curser to see the type of detail we're after and you'll just have to trust me.  I'll give you  a typical screen shoot below so you can imagine.  (Also the laptop I had to borrow for the datalogging isn't networked.  I'm typing this on my old faulty one which refused to connect to my ecu for some reason!)

Whilst this is an old screenshot of previously testing, I used similar screens for these ramp runs.  The screen can be stretched to allow you to pick up extremely detailed data.  The time increment shown on the screen above for example is 0.2 seconds. Click on the Values screen and then it gives times to the millisecond.

 

Results

Configuration	RUN1 - Larger Throttle Body with Std Airbox with modified lid to improve flow	RUN 2 - Larger Throttle Body with Airbox lid and filter removed	RUN 3 - Standard Throttle Body with Std Airbox with modified lid to improve flow	Notes
Date of Test	21/03/2022	21/03/2022	22/03/2022
Ambient Air Pressure	90.1 kPa	90.1 kPa	90.0 kPa
MAP at end of run (6,500rpm)	84.5 kPa	84.2 kPA	85.2 kPA
IAT at end of run (6,500rpm)	27.9 0C	28.7 0C	31.2 0C
Head Temperature at end of run	166 0C	168 0C	177 0C
Lambda at end of run - Bank 1	0.825	0.793	0.801	Lambda aim at WOT is progressively enrichened from 0.9 (2,500rpm) to 0.8 (6,500rpm) Run 1 data had scatter right at end point.  Both actually run closer to 0.79 than at that actual split second.
Lambda at end of run - Bank 2	0.774	0.788	0.795
Ramp run duration from 2,500 to 6,500rpm	15.717 seconds	15.935 seconds	15.837 seconds

[sus911]

Results look like typical anomalies given variables involved in this test.

Conclusion?

Looks to me like "don't bother".....

[Peter M]

Phil,

With a variation of only 1.3% for the acceleration times of all the configurations tested I think you are correct in your assessment.

I admit I was surprised as the car felt great to drive after the larger TB was installed.  This exercise once again confirms how unreliable our butt dyno is and how any claim for performance increase has to be taken with a grain of salt unless it is backed up with solid data.

I am continually amazed by how much we collectively spend on these cars based on internet wisdom alone and general trust of someone else's opinion.  From what I can see the actual dyno data posted is little better than butt dyno figures as there is invariably no "before" testing done to set a baseline and the universal use of large correction factors and of course the "add 15% for flywheel hp" is laughable.'

Without data, it is just an opinion.

 

    

[sus911]

Agreed.

Even more amazing is how the US low compression cars push out dyno numbers that ROW high compression cars could only dream of!

[Mike D'Silva]

On 23/03/2022 at 07:53, Peter M said:

Phil,

With a variation of only 1.3% for the acceleration times of all the configurations tested I think you are correct in your assessment.

I admit I was surprised as the car felt great to drive after the larger TB was installed.  This exercise once again confirms how unreliable our butt dyno is and how any claim for performance increase has to be taken with a grain of salt unless it is backed up with solid data.

I am continually amazed by how much we collectively spend on these cars based on internet wisdom alone and general trust of someone else's opinion.  From what I can see the actual dyno data posted is little better than butt dyno figures as there is invariably no "before" testing done to set a baseline and the universal use of large correction factors and of course the "add 15% for flywheel hp" is laughable.'

Without data, it is just an opinion.

 

    

I wonder if your engine with its Motec, could have made even more use of the larger TB? Again, without convenient and cost efficient access to a dyno, it's difficult to establish any gains. 

[Peter M]

4 hours ago, Mike D'Silva said:

I wonder if your engine with its Motec, could have made even more use of the larger TB? Again, without convenient and cost efficient access to a dyno, it's difficult to establish any gains. 

Mike,

I would expect my engine with larger capacity, warmer cams, twin plugs, freer flowing air cleaner and headers to flow more air than a standard 3.2 so you would think it would likely show a greater benefit, if there was one, than that if it was installed on a standard 3.2.

The Motec itself doesn't improve volumetric efficiency per sec it just allows a modified engine to be tuned easily to realise the VE potential of the modified  mechanical components such a the cams and headers.

Time and time again dyno's are misused or misrepresented by not getting a baseline with sensible industry accepted weather correction factors and employing consistent processes such as tyre pressures and doing only one modification at a time.  While ramp runs don't give a HP figure they are just as valid and are arguably more useful as they give a real life measure. 

I'm surprised more owners aren't posting ECU datalogs of ramp runs (or something similar such as speeds along SMSP front straight for example) as with a little practice, they are easy to produce and quickly tell you if your butt dyno is calibrated or not and if we have spent our money wisely on modifications.

However I realise many owners don't care if a modification provides a measurable benefit or not as many spend money for bling or bragging rights.  That's OK except when the benefits are misrepresented.

For the next Myth Busters, I'm actually going to reinstall the standard air flow meter, but run it unconnected so the Motec still uses the MAP sensor in the intake manifold.  (I'll  install the IAT temporarily in the air filter entry.)  Until I ran the enlarged TB, I would have guessed the AFM was a restriction, now I'm not so sure!   

[Peter M]

Use of 997 or 991 Condenser in Rear Wheel Well

While Kuele and others offer kits at great costs, this Finnish guy is installing a 991 condenser behind the rear left wheels of his 930 and SC

Classic Retrofit AC on 930 and 911 SC - Pelican Parts Forums 

If I lived somewhere where I had to drive at low speed a wheel well condenser would be on my wish list.  Since we only have 2 sets of traffic lights here, low speed AC performance isn’t a real concern….

[Peter M]

Face off with large chicken at Moonbi

[sus911]

Careful Pete, he's got the high ground on you.

[OZ930]

A loud Rode Island Red with it’s showy tail up has come into it’s territory.  Feathers will  fly soon.

[Peter M]

Interesting dyno comparison from Steve Wong posted on Pelican yesterday.

Fun Dyno Comparisons: 3.2 vs 3.4 vs 964 - Pelican Parts Forums

Still working my way through the implications inferred by the results.

Do 993SS cams breathe that much better than 964 cams?

How does a 3.2 intake manifold breathe better than a 964 manifold?

Why would you spend all that money on a 3.2 and then not twin plug? (By comparison my 3.4 made 10 to 15rwhp more with the second plug energised and retuned with a lot less ignition advance)

[Peter M]

Knock Bars

I got asked how I mounted mine.  Here's a photo