Another turbo thread.

[Soupaman86]

Hi, I'm new here, registered after browsing these forums as a guest for a long time.

I've returned to petrols, now the owner of a MK1 Punto 60 S, having had faster and more refined cars in the past, I know that the Punto will never be a Subaru, but I'd like to add a turbo, and could do with a little input on a few things if that's O.K.

Things I've done so far:

Lowered 40mm all round with a front strut brace.
Changed the rear trailing arms.
Water pump, tensioner, and belts.
Mist jets, and de-wipered rear.
866 cam and the head with bigger valves.

Brakes will be uprated in due coarse.

I've got to changed the flywheel as the ring gear's damaged, (starter too) as well as change the clutch due to oil contamination, and overhaul the gear box as the input shaft bearing is making a noise, but then I plan on going down the turbo route, but I'm a little unsure on the spec I should be aiming for, I'd be happy with something in the region of 90-100 bhp, my plans are:

Standard manifold with a turbo flange welded on, to this I'll bolt a GT 15, taking my oil feed from near the filter, and a return pipe to the sump. I'll have a front mount intercooler, and I'll vent to atmosphere with a B.O.V.

Pistons from a 16v 1.2 Punto instead of decompression plate, perhaps an MLS gasket and a lower rated thermostat.

Fuelling will be MF2 Aquamist as Megasquirt is beyond me and anyone that I currently know.

Would increase fuel pressure if needed.

Custom exhaust down pipe with sport catalyst, with a free flowing Sportex in the end.

Here's where I'm stuck, inlet manifold. Had assumed that I could use the Punto 75 inlet manifold and control the four injectors for boost with the Aquamist, and retain the SPI for off boost, but I believe the 75 inlet won't bolt on, have also read that some state problems can arise as it's a dry manifold.

is there anything off the other similar engines that are MPI that I can use, as I'd rather have four injectors for boost, so that I don't have any issues with a cylinder being lean, as I've read this can happen, or am I being O.T.T?

What sort of boost would I be looking at with my theoretical spec?

One other question, regarding MOT time, if I was to lower boost as well as fuelling, would that have a negative effect on the emissions, or would it be the opposite if I had the fuelling dialled as well as the boost, would emissions be cleaner?

Sorry for the long post,

Regards, Callum

 

[jimbro1000]

If you are sticking with stock engine management you aren't looking at an awful lot of boost, probably a little less than your static compression ratio would otherwise indicate. The GT15 won't provide an awful lot anyway. Finger in the air says probably 7-8psi but without knowing your exact static compression it is near impossible to guess but that is consistent with other engines built with the 16v pistons. The problem is that the stock management doesn't have any detonation detection and this can be an issue above 7-8psi (0.5bar approx).

The reality is that it will all come down to fuelling. The 5th injector is a nice way of handling the situation if you can find a suitable boost sensor and driver to run it. You could possibly get away with a bit more boost this way but again how much is guess work even with all the information you've provided.

Your emissions at idle could be cleaner as you are running much leaner than stock with the lower compression ratio but it is all managed on a closed-loop system which the ECU controls so you'll get what your given and it should be approximately the same as the original engine would provide.

As for no subaru? A friend of mine had a Punto GT that packed about 300bhp from the original engine, the car was stripped out for weight saving and was capable of beating pretty much everything on the drag strip. OK that was a turbo engine to start with but the potential is still there. The early Punto shell is one of the lightest your going to come across but still has reasonable strength. The centos are lighter but nothing like as strong.

If you're willing to forgo some comfort and spend the money on the engine (and suspension) - a 200bhp superfire engine is not unreasonable - then you have a real rocket of a car. I used to race a production spec Punto with just 100bhp that would happily out run production spec Golf GTi's, 209 GTi's, Fiesta ST's, etc all day long (until the tyres wore out or overheated generally)... the cars only real weakness was the front steering geometry which was a little delicate and prone to getting upset if I hit the kerbs too often - that and really working the tyres, the car would only do about 10 minutes on a hot day before a brand new set of rubber was reduced to junk.

 

[fingers99]

With an existing MPI set up, I'd go for bigger injectors and an aftermarket ECU everytime. Either a pre built Megasquirt, Microsquirt, or one of the others. Microsquirt will probably cost about the same as the truly horrible Aquamist MF2 and be easier for your RR to set up properly. Bosch injectors should fit the stock P75 head/intake mani and fuel rail just fine, and with a Punto, you should (check!) have enough room for a 90 degree bend from the turbo. GT17 is an alternative to the GT15 which some Cinq folk have played with.

 

[fingers99]

Alternatively, take a peek at Honeymonster's thread here for a cheap but extremely sophisticated piggy back ECU.

 

[Soupaman86]

Jimbro1000 I think I'm going to go down the route of the piggy back ECU, but I'm going to take on board Fingers advice, and ditch the concept of the Aquamist MF2.

I've not owned a turbo'd petrol before but I think I'd be quite happy at running somewhere around the 7-8 PSI mark, my only turbo experiences and tuning of such remain with the 306 XUD engines, I think I'd be more than happy with the outcome of an estimated 40hp increase, going down this route more so for a project than anything else, but I guess I could fall prone to being overly power greedy at times!

Regarding 5th injector, I'm running SPI at the moment and had looked into getting a P75 engine and using the 4 injectors with a piggy back and retaining the SPI injector for off boost, (possible problems, I know) but this is now out of the question, and from what I understand so is fitting just the P75 head, so I'll plan on running a second injector despite having read that it can cause poor fuel distribution between cylinders, however location of such injector I'm not too sure on until I research a little more.

300 brake would be nice, real nice, I do however fancy keeping the tread on my tyres for a little longer than ten minutes though!

I do like the concept behind trying to take the engine to the limit of its potential, but it'll be my daily driver, or should I say it is rather, so perhaps I'd be best off boosting slightly less than aimed for with more concentration on things like lower rating thermostat, larger radiator, oil cooler and FMIC, hopefully that sounds sensible, or would an oil cooler + turbo feeds but too much demand on the stock oil pump?

 

[Soupaman86]

Hi Fingers thanks for your input, I was going to reply sooner but I was using a phone.

Not going to be able to go down the MPI route now, but upon searching for required info (I do try find the info myself to try prevent agitating you folk) I came across a few of your posts stating that SPI with an additional injector is a bit of a bodge.

Whilst I understand the reasons and possible issues that could arise, would you advise against the second injector for SPI on boost fueling?

Also many thanks on the Honeymonster piggy back, I think when I looked on ebay they were only £139, I'm going to see about collecting the items that I will need, then write down a list of possible piggy back managements, I can then inquire as to whether the company can map the desired management, which will hopefully be the Polish one that you mentioned.

Clearance wise, I assume that I've enough room, but I'll learn from past experience, assuming isn't good enough. The fan's rather close, but this'll not be an issue, if I have to change that out I'll find something lower profile and perhaps twin.

Also, noted that I may / will need a punto GT fuel pump for fuel pressure, and two fuel regulators, one for the standard injector and one for the additional, as I'll be running a higher pressure fuel pump, hence the need for regulators if I'm correct.

I have a steel sump but thinking of getting another steel one second hand so that I can mod that whilst off the car, so I end up with a turbo kit, when I have everything, it can all be bolted on and ready for a tune, with the exception of the pistons and thermostat which I understand will be fine to install beforehand.

If I remove the pistons from a salvage 1.2 16v, would it be better to use my main bearing shells if they're in good order, (have searched for this and some people state that there's no need to change the shells if they look O.K on inspection)

Thanks for your help and input.

 

[fingers99]

I'd always check the shells (plastiguage is cheap enough and easy to use). But no reason why you can't combine a P75 head with a P60 (or P55) bottom end and 16v rods and pistons). I'd suggest a new pump insert (they're only 80 quid or so from the fuel pump folk -- easy enough to fit in and they'll be able to advise on what to use).

The principle advantages to the P75 head are -- you get a slightly better cam with it (although some late P60s have the same 866) and MPI (so, better fuel distribution and no need for a second injector or second fuel pressure regulator). It all works as one, so much easier to set up and troubleshoot.

 

[Soupaman86]

Just Googled plastigauge and that does seem fairly straight forward, thanks for clearing up the P75 head on P60 block, I had searched for that a few times on Google but didn't see much in the way of a mention so had assumed it wasn't possible, and I had guessed about just changing the insert only but again, was unsure, so that's two things you've eased my mind on.

So if I stick with a P75 head, I'll still need a fuel pressure regulator, (but just one) uprated injectors obviously, but now I'm a little confused, i'd be doing away with the SPI injector, would I use the SPI injector wire to power the MPI injectors in any way, or would the piggy back take sole control?

 

[fingers99]

The piggy back takes over, I think, but Honeymonster will be able to confirm (or one of the Polski Cento or Punto folk).

With the SPI ECU, you've got a much more reliable unit than the poor MPI Punto folk, so no real issues with uniting it with an ECU Master, methinks.

 

[Soupaman86]

Thanks for that, I've been having a look at some of Honeymonster's posts on the DET 3, and a few of his diagrams, I'm fairly sure I could wire it in, more research is definitely needed on my behalf especially with the sensors,

Glad to hear that I've at least one thing on my side that's good about the Punto SPI!

Thanks again, you've cleared up a few things for me on here, been a good help.