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Good afternoon,

 

I have been looking for a VR6 engine to fit in a kit car that my son and I are building. Right from the start we have been thinking Audi TT 3.2. However, after much reading and also the quiet realisation we probably can't afford the Audi unit....my thoughts are turning towards one of the earlier engines.  There seems to be a lot of affection for them (hence this O C) not to mention tuning advice and aftermarket mods.

 

What I need is a quick crash course in VR6 if anyone has a few minutes.  The draw of the 3.2 is the 250 BHP. How close can the other engines get to that? Not that peak power is everything, I'm really looking for a lively, responsive engine configuration that's fun to drive. I assume tuning is broadly about the usual intake, exhaust, and maybe cams?

 

Any guidance would be appreciated.

 

Thanks.

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  • 9 months later...

Hi Zangie, we are in a similar position to you. We bought a Galaxy (£500) with the 2.8 24v VR6 which we have stripped out to use the parts in a kit car and are now looking at performance mods. Not found anyone else who has made this work. What car are you building and did you go for a VR6 variant in the end? We are building an Aeon GT2. Early days, still on chassis work. Would love to hear your plans.

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Hi both,

A quick crash course:

12v VR6 engines start around 1992 and seen in Golf 2.8l and Corrado 2.9l (and others).

Toward the tail end of the Mk3 Golf (1997 ish) the engine electronics were updated to be OBD2 compliant.

For the Mk4 Golf (1999 ish) the engines were 24v with better electronics and variable length inlet manifolds.

 

See VR6 engine - Wikipedia.

 

For modifications, a lot of people used superchargers and a few use turbos.

 

Hope you both get ideas and let us know what you are doing...

 

Have fun

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12v's are appreciating in value now, thats the problem, seen good uns pretty much same price as R32 mk5's! 

 

Best off using crashed donors for electrical reasons/k line data etc, ESKONF off what you dont need, may get the odd elec fault code which you can sort or generally leave if not affecting anything, same as any conversions really, setting up the inputs & outputs used. 

 

ME7 (24v motors) best for options, earlier AUE type can be a bit tricky to define with maps missing so defs/data thinner on the ground. 3.2 best catered for followed by BDE.

 

Tuning is as said, usual NA breathing mods, don't expect miracles though, FI's the way forward for that.

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Thanks all for replying.  These little snippets of info all help to build a better understanding for me.

 

Doublestout42...An Aeon GT2...?   Well there's a coincidence, as we too are building an Aeon, (also a 2 seater).  I didn't think there were any more out there that weren't already fully built?

We bought ours as a rolling chassis so lots of work already done but heaps more left to do.  When I first posted this the VR6 was top of my preferred engine list but we have been looking at all sorts of options since then.  4 pot turbocharged engines from Audi/VW, Mazda and Saab. Ford and Jaguar V6s for which the car was originally designed around, and most recently after buying one as my daily, a Volvo 2.5 T5.

 

We had pretty much settled on the Volvo engine but whilst I was underneath giving mine an oil change I took some precise measurements and realised it wouldn't fit so we discounted it.  However, I subsequently realised it was the air con pump housing that was fouling so not a problem after all as this will of course be ditched.

 

But back to the VR6 option as this is a VR6 forum..!  Despite what I have just written above, my heart still says that it should be an NA engine. The turbos give big power but I'm willing to sacrifice power for point and squirt style response.  4 pot NA engine don't really deliver the beans  so V6s feel like the way to go.  The beauty of the VR6 is a) it is compact and b) all 6 exhaust ports are on the same side so no threading pipework under the engine.

 

Something you said in your post that has struck a chord is that your engine came from a Galaxy and I'm thinking that this is 2WD ?  My focus has mainly been on the 3.2 which are 4WD and also the majority are DSG with all the problems that that brings with it.

 

Anyway I wish you luck and we should keep in touch re our builds whether I go VR6 or not. I am in Reading, UK.

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@Zangie yes, we went for the Galaxy V6 (which is the 2.8 24v VR6) because it is a lot cheaper option as there is no 'cult' around Galaxies and it is 2wd using the same 02M gearbox as golfs etc. so for the Aeon transverse layout it works nicely. We paid £500 on Facebook marketplace for an MOT failure but still a runner. All the 3.2 options are a lot more and all are 4wd. Do-able but complex. The Sharan & Alhambara are the same underneath as the Galaxy. So far, we have removed the engine and nearly removed the wiring loom. We bought our chassis direct from Aeon as they still make them to order, did you get yours as an incomplete project? Talking to David and Keith at Aeon, straight 5s have been tried before (the Focus RS 2.5) and didn't fit as the bay isn't wide enough, same as a V8. David is building one for himself as a track car at the moment. Some links you might find useful if you don't have them:

 

Tribbecks build log, he used a 1.8 20vT as have many others: http://aeon.tribbeck.com/

Main company site: https://www.aeonsportscars.com/

Owners club: http://www.aeonownersclub.com/welcome.php

 

Like you, we want NA power for smooth delivery (a 200bhp V6 NA Duratec does 0-60 in 4secs in an Aeon). So we are aiming for an NA tune of 250bhp+ which should be plenty. Current thoughts are to do cams, injectors, single mass fly wheel, clutch. Maybe forged parts, throttle body etc. cash depending. And of course a new ECU map.

 

We are in Gloucestershire. Definitely keep in touch, will ping you my email on DM.

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Not enough airflow to justify an enlarged throttle body on an NA build plus it'd make your mapper's job harder thus pointlessly adding £££'s, nor any need for forged parts, FI R32s have done 6-700hp on near enough stock engine

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Thanks RBPE.

 

So where would you spend your money for the best BHP per £ tuning wise.  I can't see how much can be done on the inlet side with the complexities of the variable intake length system or does that get completely binned in favour of an aftermarket system.

 

I have to admit I don't have a full grasp of how that side of things really works. I understand the "roller valve " mechanism which changes the inlet route and size  but I don't follow how all the inlet tracts are of equal length when 3 of the 6 pass through the cylinder head to the other 3 cylinders.  Same with the exhaust although that would be easier to equal things out to tune out the return waves etc.

 

A quick lesson from anyone please?

 

Thanks.

 

  .

 

 

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Thanks for the link, that's a very good document.  I think it may take 2 or 3 reads before it all sinks in but a really good reference point.

 

The one thing It doesn't appear to address is my original point about all six inlet tracts are on the same side of the engine. So as this is a VR6, 3 of the inlet ports are several inches further into the cylinder head so this must affect the flow, the pressure waves and VE relative to the opposite cylinder bank.

 

It doesn't  matter what the variable intake is doing as you can't satisfy both requirements for any one engine speed?

 

What am I missing?

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Variability and the air speeds/reverberations involved in the cycle;

 

https://www.sae.org/publications/technical-papers/content/2016-28-0001/

 

Due to design complexity and manufacturing costs, the top model gets a VRIM in it's development (different design to no.1 as Schrick own the 12V rights), but it's limited to 2 variables and is plastic due to that. These still promote forced/laminar flow at certain points and is better than none but not as good as multiple variable mani due to the afore statement - so simply put - lot's of air bouncing about and is forced as and when due to cost/design prob's and testing in development like above! 

The 12v's work on a smaller/larger orifice speeding up or slowing down a set air mass, whereas the 24v's it's about the reverberating air going back and forth off the mani walls to slave it in.

 

As for mods;

1. I'd always recommend stripping and refreshing the engine before anything else, this can add power on a tired engine and gives you a solid base for longevity. Also, instead of something like cams and a map, you could have an engine builder (or you), do some porting polishing - you should also think about changing the spinny/holdy things on the bottom end (bearings and bolts), as well as squashy/snappy things in the head (like valve springs and stems) that take a battering over the millions of cycles in their life.

2. Usual filter/zorst mods.

3. For a set of upgraded cams you want a remap, add in change over barrel function of the RIM etc - prob 20-25hp with filter/zorst so 225hp or so on 2.8, 275-285hp on 3.2 - like I say though, if stripping an engine, sorting the breathing mods on the head could get the same results but add longevity.

 

That's where I would leave NA, FI isn't that expensive if you know what you are doing, adding forged parts to an NA bottom end plus head work is actually more expensive, however as most don't know how to do it all themselves they tend to look at an FI conversion costing £4k+, but that's not far off the costs of a good, built NA engine for only around 300hp!

Edited by RBPE
Comp wigged out and posted partially by accident
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