306oc - Peugeot 306 Owners Club & Forum

what would top me doing this? only problem i cant overcome in my head is the map sensor..... any suggestions??

I think supercharging and turbocharging would probably top just turbocharging your gti....


Aside from that, a plethora of things would stop you turboing it. depending on what else you've considered in addition to the map sensor.

You'll need bigger injectors, a decomp plate probably, or forged internals, an intercooler, a turbocharger, a modified exhaust manifold, a modified inlet manifold, stand-alone ecu and custom mapping, probably an lsd, a swirl pot, a dumpvalve/recirc valve, misc. boost piping, a cossie 3bar map sensor, some common sense, general knowedge, ability to read compressor charts, plenty of money... the list goes on

So really, in general the biggest thing stopping you turboing your gti is....well..............yourself..............

with regards bigger injectiors a 5th injector is what ive decided on, decomp plate isnt needed as i only want to run 6psi, got a intercooler, t25 turbo, manifold can be knocked up in a jiffy, why modify the inlet???? the current map should be sufficient or i can get it re-mapped to accomidate, got boost pipes... 3 bar map sensor??? will look into that....

Right I see you're going very low boost. I don't know a huge amount about going down the 5th injector route, But iirc you'll want to be very careful about running it lean. You'll defs need to get it mapped, you'll kill it in no time running it Lean as the fuel won't be there up high. Plus you'll need to map the 5th injector in.... I'm not sure wether youll need A stand alone ecu to do this but would imagine you will, I doubt a fifth injector can be mapped into a stock ecu...


a 3bar map sensor is what most people use as it gives the edu a boost reading so it can adjust the map accordingly. Without one your ecu will throw a shit fit and not work. That's the only way a stock ecu can be used with the supercharger conversions done by lynx, they leave the stock map sensor in place on the throttle body pre-charger, so it doesn't see boost and thus still operates!

ok thanks going to have a go next week....

Cue molten exhaust valves and holes in the pistons....

(23-09-2012, 01:02 PM)Ruan Wrote: [ -> ]Cue molten exhaust valves and holes in the pistons....

ye of little faith....

The current ECU map wont cope with boost.
a 5th injector is an incredibly crude way of adding more fuel, a stand alone ECU would be alot better.
a set of injectors off a 200SX or similar might be a cheap upgrade.
I dont think theres space for a turbo down the back of the engine so youll need to gearbox mount it.
Youll need to find a suitable source for a high pressure oil feed.
Youll need a pipe welded to the sump for an oil drain.
You will need a map sensor, at least a 2 bar but you can get a 3 bar for the same price. Remember when talking about map sensors the first bar they measure is atmospheric pressure so a 3 bar sensor only measures 2 bar of boost


The GTi6 runs quite high compression (for a 90s hot hatch) and so it does limit the boost you can safely run.


You do need to consider if its actually worth it if your only going to run 6psi of boost. I know they reckon that if you add 7.35psi (0.5bar) of boost then youll add 50% more power but you need to consider the thermal losses and your power per pound. I reckon 6psi will see 220bhp and for the money of turboing it and setting up the fueling youd be far better offf (for the sake of both reliability and cost) building a cammed 2.1.









What is your experience with turboing cars?
What s your experience on modding a GTi6?

As a general rule, everything Dumdum ever says is to be ignored if you don't want to end up scrapping your car.

However, there are elements of truth in the above post..... I'll leave it to you to discover which elements....

(23-09-2012, 02:38 PM)Ed Doe Wrote: [ -> ]As a general rule, everything Dumdum ever says is to be ignored if you don't want to end up scrapping your car.

Go and troll elsewhere Ed. I was trying to be serious/helpful.
You forget that I have done alot of the mechanical things here that others just talk about and not only that but studied engineering and have worked for Honda and a company building custom trackday/race motorbikes in my time.

Go for it... what's the worst that can happen it'll need about engine or get weighed least your trying what others just sit behind their computer chatting about

(23-09-2012, 03:55 PM)Dum-Dum Wrote: [ -> ]

(23-09-2012, 02:38 PM)Ed Doe Wrote: [ -> ]As a general rule, everything Dumdum ever says is to be ignored if you don't want to end up scrapping your car.

Go and troll elsewhere Ed. I was trying to be serious/helpful.
You forget that I have done alot of the mechanical things here that others just talk about and not only that but studied engineering and have worked for Honda and a company building custom trackday/race motorbikes in my time.

Ok Mr. Honda Engineer.

Lets talk about area under the torque/rpm graph.

Let us for a minute dwell upon the differences between the application of a turbocharger vs n/a tuning.

A low-boost turbocharged '6 with the correct compressor will eat your 2.1 for beakfast. On a race track you will probably find it a little closer, but the reality of driving a highly tuned n/a on the road is that it will be very lumpy and you'll be waiting a long time to get on-cam. By comparison the turbo will up and go. The mid-range punch will far outstrip your car out of lower speed corners, something which will be exacerbated by the 6speed box. Unless you modify the final drive or run a 1.6gti box.

Either way, bang for buck, a turbocharged rs engine will be far more flexible day to day, and far more of a weapon on the roads than a 2.1. Though the 2.1 will sound pornographic in the process of being beaten...

And there is no way a 2.1 will cost you significantly less. and be less temperamental. and probably more fun to drive more of the time.

(23-09-2012, 04:58 PM)Ed Doe Wrote: [ -> ]

(23-09-2012, 03:55 PM)Dum-Dum Wrote: [ -> ]

(23-09-2012, 02:38 PM)Ed Doe Wrote: [ -> ]As a general rule, everything Dumdum ever says is to be ignored if you don't want to end up scrapping your car.

Go and troll elsewhere Ed. I was trying to be serious/helpful.
You forget that I have done alot of the mechanical things here that others just talk about and not only that but studied engineering and have worked for Honda and a company building custom trackday/race motorbikes in my time.

Ok Mr. Honda Engineer.

Lets talk about area under the torque/rpm graph.

Let us for a minute dwell upon the differences between the application of a turbocharger vs n/a tuning.

A low-boost turbocharged '6 with the correct compressor will eat your 2.1 for beakfast. On a race track you will probably find it a little closer, but the reality of driving a highly tuned n/a on the road is that it will be very lumpy and you'll be waiting a long time to get on-cam. By comparison the turbo will up and go. The mid-range punch will far outstrip your car out of lower speed corners, something which will be exacerbated by the 6speed box. Unless you modify the final drive or run a 1.6gti box.

Either way, bang for buck, a turbocharged rs engine will be far more flexible day to day, and far more of a weapon on the roads than a 2.1. Though the 2.1 will sound pornographic in the process of being beaten...

And there is no way a 2.1 will cost you significantly less. and be less temperamental. and probably more fun to drive more of the time.

Ive had a good hunt through google images for a 200sx power graph thats not either completely bog standard or 350bhp+ and seem to fail miserably so cant do a comparison but heres the graph from Matt-Rallye on the GTi6 forum of his cammed 2.1







2.2 isnt expensive, Ive paid sub £30 for my block, and ill have a 2.1Td and S16 rods for less than £60, £400 for some 88mm pistons and thats £500 plus a little bit of machining then for the head Ive seen second hand cams on the GTi6 forum go for about £200 and the whole set up will run on standard management.

so maybe £1000 all in.

I actually really like the idea of that chris and didnt realise it was that cheap to do but the power is so far up the scale. Surely a turbo, although more expensive, will be making power much lower = more fun!

Standard management. Klol



What about balancing everything, the fact that you'll want a custom set of cams for the 2.1, the sundry irked like bearings, the injectors, the mapping etc etc etc.

(23-09-2012, 07:05 PM)Niall Wrote: [ -> ]I actually really like the idea of that chris and didnt realise it was that cheap to do but the power is so far up the scale. Surely a turbo, although more expensive, will be making power much lower = more fun!

No cos the 2.2 gives its extra power right from the off cos every revolution from idle to red line has that 10% more air/fuel mix to set fire to. Thats why some of them (esp on the 92mm crank) make such massive torque low down that kinda helps balance out the losses from the cams.

(23-09-2012, 07:05 PM)Ed Doe Wrote: [ -> ]Standard management. Klol



What about balancing everything, the fact that you'll want a custom set of cams for the 2.1, the sundry irked like bearings, the injectors, the mapping etc etc etc.

Yes Ed, We're all aware that mild (mild enough to run on hydraulic lifters) cams run happily on the standard ECU as there are many people out there running them.

Im not gonna factor in the cost of balancing everything as the turbo engine for comparison wont of been balanced although this is something Im gonna do to mine as it dosent cost a huge amount (compared to some machining)

You dont need custom cams for the 2.1/2.2

I didnt factor in the cost of bearings again cos this is something that the turbo comparison wont have and also some tight f*ckers on here re use bearings.

From what Ive read the standard GTi6 management will cope with a 2.2 conversion as all the data is within sensor ranges and the standard injectors can feed it enough fuel.


At the end of the day give me a few months and Ill hopefully have my 2.2 built up and be able to prove the point.

you sure dum because that graph looks pretty crap for general road driving. Would love to do it but the other problem is its going to feel like a even more lazy engine than the gti engine already does seeing as your increasing the stroke

Yeah I could turbo a 6 for 500 quid if you don't include all the things you need to actually make it work. Obviously I didn't include those cause you'd need the same for a 2.1 build. So the figure of 3k I had being a realistic all in figure isn't going to be competitive against your 'broad figure'. That much is obvious.

And frankly rofl at running a 2.2 on an unmapped stock ecu.

Finally you still haven't got my point about the boosted application vs na. The power is all at the top. With a forced induction engine you'll get high torque throughout a much larger chunk of the rpms, meaning more area under the torque rpms graph, and therefore a faster real world car.

don't misunderstand me here, I'm not saying you shouldn't go for it, in fact I would love you to have a go so I can hear one for real rather than just in my YouTube favourites.... I'm just saying for real world driving, a turbo/supercharger is a better investment for the effect it will have on the engine/power delivery.

It'll run on standard management, but there's no way it'll run without risking serious damage without a remap, especially cams, you're moving where the power is being made massively, the fuel isn't there for the added air going in at lower RPMs...

These engines are NOT AFM based, you can't just wang mods on and expect them to work... They're only MAP based, at WOT they're not reading Lambda values, they're closed loop so just keep running the same values unless they recieve information from the knock sensor that it's detonating, and will pull the timing off...

Also, the increase in Torque isn't from the increase in volume so much, that's down to the increased purchase the piston has on the connecting rod due to the increased crank throw... Why do you think high RPM, high performance engines are based on shorter strokes... Stroking engines IMHO isn't the way to go, you're pushing two characteristics in opposite directions... You're using cams to increase the top end ability of the engine, but then promptly increasing the stroke to make it a torquier engine which won't want to rev...

With a graph like the above, you're only ever pushing towards the redline, with an OE GTi6 gearbox, you've got two options up until 70mph to recieve anything close to full power - on the limiter in 1st at about 40mph, on the limiter in 2nd at 60mph.... And that's it... With a turbocharged engine, you've got so much more area under the graph, you've got the midrange torque, which may not have much horsepower, but you've got decent pull over a much wider area of the graph...



^ That's what Turbocharged engines are all about, the torque is in from 3500 and from 4500 to 5500rpm, you've got 95% of all the power across a 1000rpm band! Going back to the graph that you posted above, you've only ever got the full power sat on the limiter, from 5000 to 6000rpm the power increases 50hp, from 6-7k it increases 20hp... but at 3500rpm you've only got 90hp!

The days of all or nothing Turbochargers are over... Only cheap chinese turbos, T28s and T04Es have that reputation... When you look at stuff like the new BorgWarner EFRs, some of the stuff that Precision Turbos are chucking out - that sorta stuff goes straight out the window....

^what he said. perfectly put imo.

Ruan I appreciate what your saying but the OP is taking about a (Im assuming used) T25 turbo that was designed at some point before I was even born.


I do appreciate what your saying about stroking and cams moving in opposite directions but if youve looked at the milder performance cams for the 6 they dont move the peak power any further up the rev range.


Anyway for comparison

[attachment=2639]



This is based on the data contained in Petes GTi6 standard power graph and the 2 graphs below, the 230bhp is a 2.1 and the 250bhp is a S/C

http://i49.photobucket.com/albums/f257/m...Rgraph.jpg
http://img.photobucket.com/albums/v247/c...asd001.jpg



Ill remind you that the S/C will have a bit more low down and mid range than a turbod car also the S/C is running a little more boost than the OP is talking about so making a little more power. If i could find one to do a 230bhp N/A to 230bhp boosted comparison but i reckon it would be pretty interesting.

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[attachment=2640]
[attachment=2641]

(23-09-2012, 08:41 PM)Dum-Dum Wrote: [ -> ]Ruan I appreciate what your saying but the OP is taking about a (Im assuming used) T25 turbo that was designed at some point before I was even born.


I do appreciate what your saying about stroking and cams moving in opposite directions but if youve looked at the milder performance cams for the 6 they dont move the peak power any further up the rev range.


Anyway for comparison





This is based on the data contained in Petes GTi6 standard power graph and the 2 graphs below, the 230bhp is a 2.1 and the 250bhp is a S/C

http://i49.photobucket.com/albums/f257/m...Rgraph.jpg
http://img.photobucket.com/albums/v247/c...asd001.jpg



Ill remind you that the S/C will have a bit more low down and mid range than a turbod car also the S/C is running a little more boost than the OP is talking about so making a little more power. If i could find one to do a 230bhp N/A to 230bhp boosted comparison but i reckon it would be pretty interesting.

Dum the low boost rotrex charger is shit low down, and as a general rule turbos have much more lower down than a charger, if sized correctly.

The lynx low boost charger isnt a great example of what you can achieve with that application, a bigger charger Like the 38-94 They use with the high high boostengines with a restrictor ring would be better For the significant increase inow down torque it privides.

either way a turbo properly sized is a step up again in torque levels all over the rpms


also didn't Pete's gti6 make 150bhp cause it was a. It of a tapper? Or was it fuelling issues?
either way its hardly the best comparison...

Chris a 2.1 NA would be pretty interesting compared to a low boost turbo but i think for daily fun, a turbo is where its at.
My old saab only revved to 6.5k but came on boost really low down making it very very fun for general road driving and your typical off the lights to 60 race you might have with a chav in a s3.
Granted on a track, a 2.1 would be good but realistically you rarely use all the rev range throughout most gears on the road.

A supercharger (at least, Cetrifugal) will never produce the boost of low end grunt that a well sized, efficient turbocharger will... Roots blowers are better, but are still restricted to the engine speed for its maximum output... This is why people slate the Rotrex setups and one of the main reasons I wouldn't have one... They have all the disadvantages of an NA engine and all the disadvantages of a boosted engine... Unless you get a seriously big charger and allow that midrange torque to come up, it's just like an extended NA engine... Everyone goes on about it being linear, but at the end of the day - you look at what manufacturers are striving towards these days - and that's the graph that I posted above, torque coming in early, then the power going on to the redline... Not the torque rising at the same rate as the power all the way up the RPMs...

Meh, I don't care at all... But at the end of the day, a well set up, efficient turbo setup without someone getting distracted by shiny bits and sticking to the problem in hand and taking the time and effort to choose things properly, not just guestimate - it'll ALWAYS be better than an NA engine - it can't not be, forcing air down the inlet will always be a more efficient way of doing things...

(23-09-2012, 09:22 PM)Ruan Wrote: [ -> ]A supercharger (at least, Cetrifugal) will never produce the boost of low end grunt that a well sized, efficient turbocharger will

Agreed but as i keep pointing out the OP is talking about a T25 which is neither well sized nor efficient.

For the record I was costing a correctly sized turbo and properly done conversion including mapping etc, rather than a t25 knocked up on a homebrew mani... however with a cheap turbo but doing the rest properly you could probs do it for circa £2k

Dumdum, i really envy your way of working with this, and (from what i understand) you're just going on instinct and going ahead, then dealing with the consequences/results after, and so what, if the ECU doesnt cope first time round and something goes wrong, great, you have the FACTS to share next time round, honestly, go for it, do what you want, put aside what SHOULD be followed.

I'm still interested in the OP's question and a resolution.

(24-09-2012, 09:44 AM)ginge191 Wrote: [ -> ]Dumdum, i really envy your way of working with this, and (from what i understand) you're just going on instinct and going ahead, then dealing with the consequences/results after, and so what, if the ECU doesnt cope first time round and something goes wrong, great, you have the FACTS to share next time round, honestly, go for it, do what you want, put aside what SHOULD be followed.

I'm still interested in the OP's question and a resolution.

In all fairness Ginge, people only progress and learn from trying new things and probably breaking stuff. Get on Chris!

Ill put up a thread on my 2.2 lump once ive got a few more bits together, theres some serious technical issues that people overcome by using custom rods or spacers but I have a cunning plan.

Have you seen the 2.3 on the 205gti forum?

(24-09-2012, 10:01 AM)Niall Wrote: [ -> ]

(24-09-2012, 09:44 AM)ginge191 Wrote: [ -> ]Dumdum, i really envy your way of working with this, and (from what i understand) you're just going on instinct and going ahead, then dealing with the consequences/results after, and so what, if the ECU doesnt cope first time round and something goes wrong, great, you have the FACTS to share next time round, honestly, go for it, do what you want, put aside what SHOULD be followed.

I'm still interested in the OP's question and a resolution.

In all fairness Ginge, people only progress and learn from trying new things and probably breaking stuff. Get on Chris!

...is kind of what im saying, great attempt at tripping me up, again.

(24-09-2012, 09:44 AM)ginge191 Wrote: [ -> ]... going ahead, then dealing with the consequences/results after ...

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chris, i look forward to the results