Knackered old Porsche with loads of natural light - Boxster!
Discussion
poppopbangbang said:
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 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.
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!
poppopbangbang said:
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!
Aren't 2001ish onwards Passats and A4s also 06A/B architecture? Could be the best starting point?
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. poppopbangbang said:
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.
Makes sense!So how long before the PPBB 1.8t conversion kits are available?
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
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 I guess the question is ‘which OEM’!
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!
poppopbangbang said:
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!
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.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!
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 contact@porsche.co.uk 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
poppopbangbang said:
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!
You’ll be able to get the car re-certificated for emissions to show it meet the NOX requirements?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!
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.
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.
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.
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.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. 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.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
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. 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.
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.
poppopbangbang said:
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.
I guess from your work you have experience of doing this. I can’t imagine the cost won’t be insignificant!Gassing Station | Readers' Cars | Top of Page | What's New | My Stuff