Tuning the V6

deian · Post by **deian** » 17 Jul 2007, 20:27

Hi,

Firstly I won't, cos 1, i'm skint, and 2, i can't be arsd.

But the ES94J engine featured in the Xantia V6, as most of you know, it's a 24valve 3.0 engine with 194bhp.

I'm wondering if any of you have or ever will or considered tuning this engine. In this I mean a free flowing exhaust, air muffler (can we get this) aftermarker ecu, turbo etc.

How much BHP could be pushed out of this engine it it had some work done to it?

Your thoughts would be interesting.

MikeT · Post by **MikeT** » 17 Jul 2007, 20:34

Nitrous it

Post by **CitroJim** » 17 Jul 2007, 20:51

MikeT wrote:Nitrous it

I like

And have a V6 grenade!!!

194BHP from a 3.0L engine is a bit on the low side and if it is typical of a PSA engine, the bottom end will happily take double that. Legend has it that the XU10 is good for 300BHP.

The simplest way to BIG power is to (twin) turbo it and run bespoke management. I guess the basic gas-flowing in the head is pretty near optimum and there would not be a lot to be gained from after-market induction kits etc. Trying to get too much out of it as a normally aspirated engine can give it an unpleasant character for normal use in that bottom end power may suffer and make it all peaky at the top end. The great thing about turboing it is the standard mild cams are just the job for it and no change will be needed. the Compression Ratio might be a bit high for serious boost though.

The other approach is to look at what Renault have done with the Clio V6 which I believe uses the same basic engine. Was it not a joint PSA/Renault design or am I thinking of the old Douvrin V6 here?

How about supercharging it? All the benefits of a turbo except you only need one and there is no lag to contend with. I note in this months PPC (Practical Performance Car) there is a company making superchargers that are small and look like the turbine side of a turbo has been chopped off and replaced by a pulley. The compressor looks like a conventional turbo. I guess even a modest boost of say 5psi would make quite a difference. In fact, if the standard V6 management is MAP-based it might just accept a modest boost without complaint. You might not even need an intercooler.

MikeT · Post by **MikeT** » 17 Jul 2007, 21:16

I agree with Jim, forced induction ............. and then nitrous

Stempy · Post by **Stempy** » 17 Jul 2007, 21:17

I have often thought of a nitrous kit but I don't know if the autobox would handle it.

I read somewhere that these engines have been take up to 800bhp but I doubt that was with many of the original parts

deian · Post by **deian** » 17 Jul 2007, 21:35

citrojim wrote: The other approach is to look at what Renault have done with the Clio V6 which I believe uses the same basic engine. Was it not a joint PSA/Renault design or am I thinking of the old Douvrin V6 here?

I think it was modified after getting the VANOS, to go into the clio v6, wikipedia also mentions this too.

I remember seeing a fire damager clio v6 in the local scrap yard a few year ago, maybe the engine would drop right into a xantia.

jeremy · Post by **jeremy** » 17 Jul 2007, 22:08

I think there are 2 series of V6 engines here. The first was th PRV (Peugeot Renault Volvo) V6 venture of the ealry 70's - which was an entirely new engine built in a new factory (Douvrin I think) and fatally flawed in that it had a 90 degree V angle - which is appropriate for a V8 but not a V6 (as Ford also found out - Essex - British was a 90, German ones were 60's)

As such generally the only thing the PRV engine was good at was consuming fuel which it did better than proper engines like Jaguars of a litre or so bigger. Volvo even had different timing on each bank at one time to disguise its roughness problems.

Renault eventually solved some of them properly - by making the crank with off set big ends - so that each journal in its original configuration was now split into 2 offset by (15??) degrees which made the horrible thing think it was a 60 degree engine and work like one.

It may be Citroens desire for mechanical excellence that prevented this thing ever getting into the CX but it did appear in the XM series 1. It may well have had the Renault modified crank.

I think XM series 2 and Xantia have a different and properly designed engine with a 60 degree angle between the cylinders. This doesn't stop it being rather poor in its output - which is surprising for a company like Peugeot which has always suffered from the lack of a decent engine for its large cars - something which would make them comparable to BMW and Mercedes.

Had the Xantia engine had the efficiency of the BX 16 valve engine it would be producing about 250 BHP - so its reasonable to say that in NA form its 55 BHP or roughly 25% deficient. Ok its grown a catalyst - but some tuners recon that 200 BHP is obtainable from the BX engine by simply enlarging the valves and gas flowing the head.

Note we're not even talking variable valve timing or turbocharging here.

I've never really understood why manufacturers produce low powered engines - after all a decently designed engine will have the same number of bits as a badly designed one - and all will use the same basic fuel injection system - so that's only software - so the cost difference is only the development - not the individual manufacture.

MikeT · Post by **MikeT** » 17 Jul 2007, 23:04

Stempy wrote:I have often thought of a nitrous kit but I don't know if the autobox would handle it.

I read somewhere that these engines have been take up to 800bhp but I doubt that was with many of the original parts

As it happens, an autobox is better able to withstand the extra forces than a manual,

Mandrake · Post by **Mandrake** » 17 Jul 2007, 23:32

MikeT wrote:
Stempy wrote:I have often thought of a nitrous kit but I don't know if the autobox would handle it.

I read somewhere that these engines have been take up to 800bhp but I doubt that was with many of the original parts
As it happens, an autobox is better able to withstand the extra forces than a manual,

How so ?

Autoboxes are tuned specifically to match the output and torque curve of the engine it is mated to - things like the kickdown and changeup speeds would be inappropriate if the engine suddenly had a lot more power, not to mention that the clutch packs could be overstressed.

At least 1st and 2nd gear on an auto is also transmitting power through the torque convertor.

A 25% increase in power it could probably withstand (with reduced life of the clutch packs) but not drastic increases...

Regards,
Simon

MikeT · Post by **MikeT** » 18 Jul 2007, 09:59

Hi Simon,

I have no real idea how, I should have qualified my statement with..... "I was informed by a retired drag-racer, builder of dynanometers, N2O systems and robotic electronics"...

Mandrake · Post by **Mandrake** » 18 Jul 2007, 11:46

Hi Mike,

I think the disconnect here is that I was talking about an unmodified autobox dealing with lots more power than it was designed for. Not whether automatic's in general could handle that power... For very high powered cars they often do use auto's simply because the time it takes to change gears looses you too much acceleration...

Regards,
Simon

Village · Post by **Village** » 18 Jul 2007, 14:06

glad to see I'm not the only PPC reader in here. It's a great mag, I'd highly recommend it!

Kowalski · Post by **Kowalski** » 18 Jul 2007, 14:36

Gearboxes are spec'd for the amount of torque they can handle not power, as long as your mods don't increase the amount of torque an engine produces the gearbox will be fine (assuming it's a manual). Turbocharging and supercharging increase torque which is bad for gearboxes and clutches.

Autoboxes additionally have a torque converter and the more power you feed through it the hotter it'll get so the torque converter limits the power an autobox will happily handle, so if you want to put more power through an autobox without killing it you have to uprate its cooling accordingly (oil coolers / heat exchangers etc)

Your standard gearbox will have some headroom for more power / torque / hotter climates etc so you won't break it with small mods, but really big mods will kill something.

MikeT · Post by **MikeT** » 18 Jul 2007, 17:26

Mandrake wrote:Hi Mike,

I think the disconnect here is that I was talking about an unmodified autobox dealing with lots more power than it was designed for. Not whether automatic's in general could handle that power... For very high powered cars they often do use auto's simply because the time it takes to change gears looses you too much acceleration...

Regards,
Simon

Hi Simon,

I was going on the assumption this thread was relative to power increases that didn't require engine (or transmission) strengthening. The engineer was talking about unmodified cars in that auto boxes are stronger and more able to accept the power increase better than a manual may. I may be mistaken in what he implied but that was the impression I came away with.

Obviously you and others know far more than I about current boxes so I'll shut up now

rossnunn · Post by **rossnunn** » 20 Jul 2007, 19:39

I'd have said, out of turbo charing or supercharging, the latter would suit the V6.
The V6 being mostly about smooth power delivery with plenty of torque.
A Turbo could be too 'top end' for it, where as a supercharger will give a similar smooth(er) power delivery.
I've always said the Auto is the best box for a v6 but thats just my opinion. But don't forget the Auto will be ECU controlled too so - in theroy - one could have it re-tuned to match the new power/torque curve, adding blips to the downchange, faster, harsher changes etc - in theroy.
Of course this wouldn't solve the need to upgrade the internals to cope.
I've been told there isn't that much to be gained by running a new ECU map (superchips etc), but more power can be eaked out from the modification of the intake & exhuast manifolds.

Here's a Turbo kit for the V6:

http://www.dp-engineering.nl/EN/project ... _turbo.php

& a Supercharged V6:

http://www.pug-performance.com/gallery32.htm