PRV engine

Sat Dec 8 14:41:04 GMT 2001

Hello Huw,

this is the later 4V engine. It has Cosworth Pistons and seems to have
very strong (and heavy, 833g) rods of unknown manufacturer.
Do you want to share some details of the engine of your friend ?

Bernd

-----Ursprüngliche Nachricht-----
Von: Huw Scourfield [mailto:huw.scourfield at lineone.net]
Gesendet: Freitag, 7. Dezember 2001 18:49
An: diy_efi at diy-efi.org
Betreff: Re: Intake manifold construction, intercoolers

Is this the 2V per cylinder PRV or the later 4V one, I have a Volvo
version
under the bench in my workshop, know someone who runs one at 30 psi
boost,
pretty impressive!
    Huw
----- Original Message -----
From: Rausch, Bernd <br at rnt.de>
To: <diy_efi at diy-efi.org>
Sent: 05 December 2001 14:00
Subject: Intake manifold construction, intercoolers

>
> Vibration is a point I did not think about before.
> Does anyone on the list run an air/liquid intercooler and can confirm
> the sizing information from Spearco ? I thought that an a/l coolder is
> more effective and smaller in size than an air/air cooler.
>
> The engine is a Renault/Peugeot V6 3L 24V, with Garrett GT twin
> ballbearing turbos (GT25 Turbine, T3-60 compressor). max RPM is 7200,
> boost will be about 1.2-1.5bar. The ECU is a Pectel T6M.
>
> Bernd
>
> -----Ursprüngliche Nachricht-----
> Von: Kevin _ [mailto:kiggly at hotmail.com]
> Gesendet: Mittwoch, 5. Dezember 2001 05:52
> An: diy_efi at diy-efi.org
> Betreff: Re: AW: Intake manifold construction, intercoolers
>
>
>
> > > Heck, then make it a 7 butterfly system.  Or even 8.
> >
> >To what end? Idle control? Throttle re-opening response by closing
> >off the plenum as well as the runners?
>
> KART cars last year (and probably this year too) used an extra
throttle
> that's on the plenum and electronically controlled to limit boost.  I
> guess
> they found they could react faster there to limit a spike event than
> they
> could with controlling the wastegate.  I'm guessing they also have a
> good
> spike wanting to naturally happen after <100ms shift (I don't know for
> sure
> what their shift times are).
>
> >Opening the throttle to a large plenum will require the turbo to
> >fill that volume as well as that of the runners.
>
> If you do a throttle before all that volume like you were saying, its
> really
> going to have terrible throttle response.
>
> >OTOH, if you instead throttle the runners, the 'plenum' is already
> >filled with high-pressure charge and starts to fill the runners
> >sooner from the reservoir in the 'plenum'. As the throttles close,
> >the reservoir accumulates some pressure and a subsequent re-opening
> >of the throttles can benefit from the store if the over-pressure
> >hasn't bled out through the turbo.
> >
> >Which system will have less lag?
>
> The system with 6 throttle plates will have less lag.  It should also
> have
> much, much better throttle response.  You will have to make a plenum
of
> air
> pressure from all 6 runners past the throttles though to get a MAP
> pressure.
>   This can just be 6 lines tee'd together, just keep the lines as
short
> as
> possible and use, probably, 1/8" or 3/16" diameter hoses.
>
> >A great number of successful competition vehicles do use separate
> >throttles; typically slide-throttles because they can afford them.
> >In terms of flow at part-throttle, the slide-throttle offers little
> >advantage at much greater risk of sticking (or leaking in typical
> >setups).
>
> You can't use a slide throttle on a street car though.  There is
> terribly
> inconsistent flow through them at part throttle.  I liked the stratus
> touring car that had barrel throttles though, those were cool as hell!
> They
> split at the middle and rolled away (like double-doors opening) to
make
> a
> completely smooth runner at WOT.  Slide throttles are your best bet by
> far.
>
> >The shafts will have to be thin to minimise obstruction at WOT.
> >The shaft has to be 'machined' to attach the butterflies.
> >Given the flow rate and engine capacity, each runner would be
> >around 70 mm diameter with a similar size of throttle plate.
>
> 70mm???  For what, if you're going to have 100%VE at 12000 rpm?  What
> rpm
> will the motor go to?  I'm guessing you'd need somewhere in the low
50mm
>
> range.  Smaller is better as long as its not a restriction because if
> you go
> too big the throttles just end up becoming an on/off switch.  For a 2L
> NA
> engine going to 8500 rpm and making ~300hp, we found that 52mm was the
> smallest that we didn't lose any hp.  Anything bigger than that didn't
> gain
> any hp at all and just made the engine more difficult to drive.
>
> >One could run the shafts on bare aluminium, but that's not very
> >durable. If the runners are close together, 4 bushes is sufficient.
> >You'd gain nothing (except profit) by using ball bearings or by
> >chroming the shaft. More bearings than necessary increases not just
> >the expense of the bearings, but also aggravates alignment.
> >
> >No seals are required on the shafts as the shafts are inside the air
> >distribution box. The only part of the throttle actuation that
> >requires a seal is the Bowden cable entry.
>
> You'll have to be VERY careful about thermal expansion of the engine.
> This
> is without a doubt the most difficult part of this entire system.  You
> need
> to make a setup that holds the butterflies aligned within the trumpets
> or
> else they will bind up.  This seems trivial, but it really requires
some
>
> attention.  I would put a pair of ball bearings on each butterfly and
> join
> the butterflies from cylinder-to-cylinder with fittings that allow
some
> axial growth.  http://www.zeromax.com has some neat couplings that can
> get
> this job done well.  I haven't used them, but they really look like
the
> perfect part for this application.
>
> Just wondering though, but why don't you just make a normal-ish intake
> manifold and mount the intercooler away from the engine?  This is
> normally
> much easier to do and you don't have to worry so much about heat soak
> from
> the engine getting the IC hot.  You're also talking about mounting
> something
> big, heavy, and with very little thermal expansion (as long as you
keep
> the
> water cool that is) on top of a somewhat high vibration environment
that
>
> goes through wild temperature swings, expansions, and deflections.
Its
> just
> a recipe for a part thats going to be difficult to make last very
long.
>
> If you go through and make it, I'd love to see some pictures!  Just
> curious
> also though, what rpm range, boost range, and displacement are you
> planning
> for this V6?  I believe you mentioned a 650hp goal...
>
> Kevin
>
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