Knackered old Porsche with loads of natural light - Boxster!

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squareflops said:

I found changing the rear tf arms on mine made a huge difference. I could wiggle the old bushings with 2 fingers
when they came out, awesome to feel the improvement of the new ones!

I might get some spacers for mine

I can only recommend them, both aesthetically and because it takes the edge off the rear spring rates a little.

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MrBen986 said:

Stunning pic, the spacers nicely fix the under-wheeled look they can have on 17's. The 986 really was an elegant design.

They've aged superbly well really, very different design language to modern Porsche but the still look fresh. I am one of about three people that think the fried egg headlights have aged well..... but only if they're litronics that had no "yolk" to begin with

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Heaveho said:

Other than appearance what benefit do spacers offer? I've always understood them to place more stress on wheel bearings etc? I removed the 15mm rear and 7mm fronts on mine when I bought it because of this.

They allow you to tune the roll centre of the vehicle, fine tune effective spring rate and tune the under/oversteer characteristics of the chassis as well as all the obvious aesthetic reasons. Realistically in race car world you'd do this work then get your race wheels produced incorporating the relative offsets you'd ended up at etc.

With regards wheel bearing loads, how often do you buy tyres based on them being the same weight as what the car did sign off on? That's pretty much the difference with the size of spacer we are discussing here when it comes to wheel bearing load. Porsche will happily sell you a set of spacers from the Tequipment catalogue for example. Note we're talking about small spacers here, not the Carlos Fandango 50mm jobbies

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A small update on the Boxster following it's first MOT with me, having had a good poke about underneath there was nothing that jumped out aside from the rear arms needed replacing as the ball joint in both sides was just showing play as identified by COG at the recent setup. To be fair these probably would have passed but hey lets put some new bits on it!

New Pankl arms:


And with an original from the car, it had clocked up just shy of 100K miles on these!



Fitting was very straightforward as the captive nut on both sides behaved and stayed captive so just over an hour for both sides from start to finish. I did them the easy way by pulling the rear arch liner out and accessing through the wheel arch.



It is proper road car filthy compared to the 996 but then this is meant to be the dirty daily so I suppose that's okay.... Coffin arms are relatively recent despite their looks with less than 10K on them and aside from some stuff looking a bit grotty it's actually in pretty good nick all round.



Passed with no advisories which considering how little mechanically I have actually done on this car is a testament to the previous owners keeping up on things:



I then went on holiday and in an effort to make me not friends with it any more it locked me out, the alarm system had gone into sleep mode whilst away and unbeknown to me the drivers door lock had packed up at some point in the past weeks. Which meant I couldn't unlock it on the remote or on the key. After putting the hammer down I got into the wheel arch liners to discover the emergency release wasn't where it was meant to be etiher, so with a bit of further "sign of a mispent youth" which I won't detail on a public forum I got the bonnet popped and was able to reset the alarm by disconnecting the battery.

No part of me was impressed by this



So door lock is now on the to do list but as punishment it's been banished outside as the 911 is back shortly and wants significant putting back together'ing!



On the bright side the new rear arms

Edited by poppopbangbang on Thursday 4th May 22:16

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Whilst collating new bits from the parts store for the 996 today I found the battery clamp that I was supposed to fit before it was MOT'd recently..... I think mentally I had been putting this off as there was obviously a reason it didn't have the correct one fitted - someone had done a particularly impressive bit of bush engineering to use the next bolt hole down.

A brief inspection showed why and in keeping with said bush engineering I resorted immediately to pure hope by sticking a tap in a pair of needle nose mole grips because surely that thread in the battery tray was fine and could be salvaged without even removing the battery:



This is the first time this has ever worked I was sure it would be stripped or have half the original bolt left in it but no, with a quick tapping I was able to wind a bolt in without issue:



I think in the past it has had a larger battery fitted which was later replaced with the correct size but the threads in the hole for the original size battery had corroded in the mean time - the battery tray used in the Boxster and 996 is pretty handy really as it supports multiple battery sizes with the same clamp and tray by offering options for where the clamp is bolted down.

Either way one more job done - back to the 996!

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Hmmmm......

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RM said:

poppopbangbang said:

Hmmmm......

VW 1.8T 20v?

That happens to share a common bell housing pattern with the gearbox a 2.5 Boxster has.....

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eltax91 said:

Noooooooooooo

Possibly, it's in the investigation stages at the moment but a 500bhp Boxster that weighs less than the original appeals somewhat!

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eltax91 said:

Oooh naughty.

I have no idea, but is the rest of the driveline up to 500hp without major changes?

Depends how good you are at calibration and correctly specifying the engine really, the sensible limit for it all is about 300ftlbs of torque which at 8500RPM gives 485bhp. Sneak that up to 330ftlbs and it'll make over 500bhp at 8000 RPM. As always power isn't what breaks things, twisting force i.e. torque is, hence why it's important to get it revving (it can do more useful work in the same time period).

It's also why a pretty big turbo is important coupled with a decent sized wastegate and accurate boost control. In this case I'm thinking an externally gated GT3076 is about right although you are getting up towards the top end of what that will do but going bigger hurts response and power band. As always it's a game of compromises between boost threshold, response and air mass delivery. A short intake path and low inlet volume will help too so we're really talking charge coolers built into the shortest air delivery path or even the intake manifold (ala current BMW).

Clutch wise a single mass flywheel and a single plate clutch will do just fine so driveability will be very similar to original. Sachs produce a couple of suitable single place uprated clutch options which depending on friction material choice will do 310 - 370 ftlbs reliably.

When you start running the numbers on this it begins to look better and better. Useable power band is circa 4000RPM which is pretty similar to standard Boxster, weight will be around 15KG less than standard, mass distribution is essentially the same, driveability has very little compromise to it and the vehicle operation is essentially as per standard with some caveats on minimum fluid temps etc.

I'm not saying I'm doing this for sure yet but the initial investigations look very promising. Some further work is required on front engine mount, charge cooling, catalytic system (as I like all my stuff to be lower emission than when it was new) and engine control system - specifically with regards to if I'm building this as a fully analogue car with cable throttle and no TCS or a DBW car with TCS and an OE (probably ME7.5) engine controller.

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amstrange1 said:

I like the idea of this. Quite a few in the USA seem to have done it too, and the 1.8t has plenty of goodies available for it.

Could be a nice side hustle in selling conversion kits I suspect?

The ones in the US have been done using the 058 block which is longitudinal from the factory (so different sump, inlet manifold etc.), it's also quite different to the later 06A block in terms of how the oil pump and water pump is driven and a few other bits.

I want to use the 06A block which is mostly available in transverse configurations but it all looks very possible to make one longitudinal using bits of Audi A4 etc. advantages of the 06A block are better ancil packaging (internal water pump), chain driven oil pump, much more compact FEAD options, larger selection of internals etc. etc. but not as straight forward regarding front engine mount and general longitudinal'ness as the earlier 058. It's a better option for this though I think!

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RM said:

Oh please do it. And document it as much as possible, as if an open source project. Outlaw Porsches used to be the preserve of those that loved the cars but did not have the budget for a recent Porsche. That has changed and it is now for the well off.

Even better do a low cost, second hand parts version with around 300bhp/lbft. I know with your engineering background you like to push things without too much concern for budget but a low cost plan would be fascinating. Boxsters with knackered engines are cheap due to the rebuild costs of the flat six. An alternative route to fix and end up with a great car would be amazing.

Everything I am considering would let you stick a standard 20V from a TT in there which with a few cheap bits will do 280 - 300bhp and similar torque (most of the bits that require changing on a TT to do that you'd be changing during install anyway). Once you sort out the electronics architecture and engine install bits it doesn't really make a different to the chassis integration what parts are inside the motor or how big the turbo is

I've just been going through some wiring diagrams and it does look entirely feasible to run the whole thing on ME7.5 which is a nice, modern ECU (TT, Golf GTI etc.) with a torque based calibration, dual sensor knock control, wideband O2 sensor support etc. etc. basically something which would take an awful lot of calibration work on an aftermarket ECU to end up with something not quite as good. It's also infinitely mapable with £500 of of the shelf kit. If you were doing the above standard engine install you'd just delete the immobiliser in the ECU and away you go!

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amstrange1 said:

Aren't 2001ish onwards Passats and A4s also 06A/B architecture? Could be the best starting point?

I looked at this originally as it makes sense right..... but the FEAD has a lot going on, including parts to run an engine driven fan all of which makes it quite wide at the bottom. Some of the coolant hoses / hard pipes are a bit inconvenient (as the engines designed to have the rad pack directly in from of it) and it also has the wrong cambelt covers for carrying a front engine mount which is required for the Boxster install. By the time you've swapped all that over it's a lot cheaper to just buy a longitudinal sump and oil pickup.

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GT2876R is on standby so there's definitely a plan forming - although the Boxster remains in one piece for now I've completed a load of white board scribblings and general working out

The 06A 1.8T is about 50KGs lighter than an M96 but by the time you've added a larger exhaust manifold suitable to carry the above turbo and all the other bits it's actually only 15KG or so different. What's more interesting is that the balance of the car doesn't really change (less than 1% by my workings out) and whilst the engine is taller than an M96 the M96 sits a bits higher (due to the clearance needed for the exhaust manifolds and sump) so impact on COG is pretty minimal. Basically you can throw all the 1.8T stuff in the back and it makes three fifths of naff all difference to how the car will actually handle.

As for the actual install there is bags of space on both sides with a 4 Cyl in the bay so packaging of intake manifolds and exhaust manifolds / turbos is quite straightforward. The standard side vents also work well for feeding an air filter and general cooling air flow (almost like they were designed for it )

I've put a bit of an engine spec together that should be stout enough for 500bhp, although that will be a bit of a stretch goal as if I do this it'll start at 300 and a bit working up to 400 and then circa 500 to research the thermals of the install etc. I am pretty sure low 400's will be cake but above that it's likely to get fairly warm in that bay and it'll start to struggle with coolant temp control due to the rad area available and likely catalyst temps but we'll see. Basic spec of the motor will be:

- 06A Block bored to 81.5mm to keep as much meat in the block as possible
- AUG "Big Port" Cylinder head
- Wiseco forged pistons with coated skirts, there are arguably more modern piston designs available now but I've used Wiseco pistons many times back in the day and I'm comfortable with the clearances etc. required.
- 8.5:1 compression ratio, so a little down on standard but I suspect I'll need that for big boost on pump fuel.
- BAR-Tek X Beam Steel Connecting Rods
- Supertech inconel exhaust valves
- Supertech valve springs
- Ti valve retainers
- Steel billet crank gear
- BAR-Tec coated lifters
- High capacity 25mm gear oil pump
- ACL Bearings throughout.
- ARP crank bolt, head studs etc. etc.

Which based on previously experience should be good for mid-400s at sensible revs and provide a path to north of 500 with just a cam profile and turbo swap (it might do it on the 2876 as it's got a big T3 exhaust housing on it) with decent reliability.

If I do this then I want it to be as OEM as possible, which means a production car ECU with all the benefits and complexities that brings. Big requirements for me are production car level knock control, catalyst management, wideband lambda and the ability to relatively easily calibrate it. Really this means Bosch ME7.5 from a later Golf Mk4 or similar which is going to be quite an integration effort with the 986 as it's generationally different and I still want the stock OBD2 port to work It also means I'll need to convert the Boxster to DBW pedal, which sounds simple as later ones were DBW anyway but that pedal I don't think will work with the ME7.5....... if it wasn't for wanting knock control and emissions compliance and those two things being a massive undertaking on an aftermarket ECU it would so have a Motec on it

So as it stands I'm building the engine (blocks off to the machine shop tomorrow) but am still considering what car it's actually going to go into..... I'm about 75% certain it's going in the Boxster

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Om said:

“I want it to be as OEM as possible”

I guess the question is ‘which OEM’!

Well VAG covers all bases now with regards the ownership of Porsche and platform/component sharing

A more accurate way to refer to it is OEM functionality (so catalyst light off control, management and temperature optimisation along with a functional OBD2 port etc.) as if I do this then I'm going the whole hog, doing the emissions certification and exempting it from ULEZ as it'll be Euro 4!

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Om said:

Nice. As an aside I understand the 2.5 can be exempted/rated as Euro4 with a certificate of conformity from Porsche. Easier but not as much fun/tinkering.

Good point to raise! The NOX on the 2.5 is below the Euro 4 maximum limit so with a COC from Porsche (e-mail [e-mail] and ask for the form) you can absolutely get it ULEZ exempt, remember to do it for any other ULEZ you want to use the car in too as in a fit of joined up thinking from our illustrious leaders, they all use separate databases

Edited by poppopbangbang on Wednesday 30th August 11:54

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Mikeeb said:

You’ll be able to get the car re-certificated for emissions to show it meet the NOX requirements?

Yes, I'll use MIRAs emissions lab for actual testing as even though on car systems exist now apparently the DVLA determine it needs to be done on a rolling road.

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GhostWKD said:

Was totally on board until I saw the 20vt One of the most soulless engines I've had the misfortune in having in some of my cars. TFSI 2.0 was such a step on, so eager to rev vs the 1.8T which just ran out of puff so early on and didn't reward hanging on for the extra revolutions. Maybe a better turbo would help that but I'm basing it on my experience in my 8L S3 vs my 8P S3.

When you're only really using the block and the head everything's possible. I've a reasonable amount of experience with this engine in a motorsport application where we ran to 8600RPM and made power all the way up with the boost still hanging in at over 2 bar.

Here's a few to listen to that rev to similar with a bit less boost - https://youtu.be/CeXMqxykCGI?si=9RpMIp0qGyvgT1wS

It's a key part of this that it makes the power without making silly torque figures to keep the gearbox and driveshafts reliable so it'll definitely rev!

Edited by poppopbangbang on Wednesday 30th August 16:51

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gofasterrosssco said:

Interesting with the 4-cyl engine. Is the 5-speed 012 gearbox / 'transaxle' up the torque output of your proposed engine set up? Nice project and interesting to see other engine options being considered.

For me the Audi V8 'option' coupled to the original 2.5 ratio gearbox would be more up my street, although that would add a small number of kg's.

Short answer is yes they'll be fine, long answer is going much north of 300 ftlbs will impact reliability significantly so the target torque for this will be in the 300 - 310ftlbs range. That means to make reasonable power it has to rev - the gearbox is able to do circa 8000RPM input shaft speed fairly continuously if the gearbox oil is up to the task and oil temps remain under control.

Rounding up/down a bit 310ftlbs gives us 450bhp @ 7500rpm, 475bhp @ 8000rpm and 500bhp @ 8500rpm so pretty sensible power targets given the rev range we're working in and gearbox strength.

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Mikeeb said:

I guess from your work you have experience of doing this. I can’t imagine the cost won’t be insignificant!

I'm building this in the same double garage that I rebuilt the 996 in, whilst it's a very nice double garage with a good amount of kit nothing I'm doing can't be done by someone else in a similar double garage and these certainly aren't limitless budget builds!

We're not talking a full emissions calibration program here but rather validation that the details on the COC for a 2004 Golf GTI are still valid for that engine in this chassis - that's not "easy" but it's a job where most of the work is on me to get right way before it goes on the emissions dyno - assuming I haven't already cocked it up with the piston choice but time will tell

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sdh2903 said:

Or are you wanting to carry out getting the pukka approval purely as an engineering project?

Mostly this and it's a good excuse to quiz TFL on all the gaps in their documentation!