Martin’s PRV bone yard…

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Just some side thoughts...

...was this a 3ltr even fire unit, just looking at the front timing case cover?



what ever happened to this setup, did it ever get to do anything useful, anybody know?



This is interesting, the rad fans up by the bulkhead, I presume pulling air from the high pressure point in front of the windscreen and exit air below the car. Does anybody know why this was done, if it was more technical than just shunt damage?



This little sequence is for Will, I have the modified turbine housing with the waste gate feed that matches your T3 turbine from this car buried some where, I will dig it out, you can see the separate waste gate line under the main exhaust. Pictures from BigM some time back, he had the remains... (not my build, just bought some of the parts, most of it due to condition post fire was scrap though when it came down to it...)

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Just a quick interlude / heads-up... wiring- as said many times it's getting old in these cars, and needs attention. We have seen a few fires of unknown origin, but my betting is on the source of ignition being electrical faults. Many sources, hardened, cracking and degraded insulation in the engine bay (old PVC), contacts and connections through hot spots of poor joints and high resistance through corrosion... these all add up. So as you go into the winter, and start using the heavier current drawing equipment, then please check these things out. The below is a fuse box that has seen better days, the melted fuse base is for the rear heated screen, and there is evidence of corrosion and oxidisation on all the fuses and contacts through damp ingress...

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... back to engines... well, with the P4 at the back end stages, bi-turbo gone, top-end and turbo upgrade package went out last week, JonV's getting ecu mapping post turbo revamp drawing to a close.... it's time for some more fun!

Hence, two new engine packages in development:

1. 3ltr even-fire bottom end, later stronger 24V rod and fastener, 24V n/a piston machined to a flat top, and shorted pin with aluminium spacers giving a much reduced reciprocating mass. So a tweaked OE bottom-end that I have enough spares, so no cry if it breaks. The block is of the oil squirter variety, and this chosen mainly to keep the OE pistons within their thermal limits on long full power runs. Liners and pistons all machined, deck honed, and a piston ring set has been made up to ensure good ring seal with sufficient thermal capacity to be pushed into forced induction duty. This will be topped off with modified 3ltr heads and a roller cam setup. So it should be yum yum... and then possibly bang, but you've got to have an oil pan failure every so often to know you are alive!

2. 2.5ltr approx, forged H-beam rods, forged pistons, cross-bolt block, and lots of goodies. This will be topped off with modified 2.5ltr heads (flow results already published), and again this will be going roller cam set up. This one has a one-off, machined from billet EN8 light flywheel, and a specialist single organic plate Sachs Racing clutch. This should be very grippy yet forgiving enough for occasional road duty. This will make a very rigid and light rotating assembly on the 63mm stroke crank (noting the difference in weight mentioned before), and the very light forged top end should make this unit very interesting for short circuit, rapid transient engine response demand... remember the restriction on the engine is the inlet valve, all else being taken care, then this setup has the same flow capacity for cylinder filing as the above unit, but with smaller lung demand, she won't be the usual asthmatic PRV!

The 3ltr is getting a twin AP Racing clutch basket and a modified OE flywheel, as there is no expectation of road manners...

Cranks off being machined and balanced to their respective assemblies, the rest of the bottom end assemblies have already been completed.

Interesting note, the 2.5ltr even-fire OE crank is Nitride treated from the factory! Hence, it is much more wear resistant than any of the other OE PRV cranks, so be aware the 3ltr even-fire crank is not, and is left in its soft surface finish state… Again proof of the production cost cutting options implemented by the PSA organisation, and the general nature of the intended applications of these engines being driver behind the production process decisions. The same is true of the 24V engines, so I guess this is also true of the bi-turbo and A610 variety i.e they carry a soft surface finish crank! Pity… Anyone able to better comment? However, the interesting point about this is the detail the Renault engineers had put into our 2.5ltr turbo unit, as I have said many times before. The harder you look, the more you have to respect what they achieved given the limitations imposed, and the fact this was a consortium engine with compromise abound. The 2.5ltr crank is a nice piece… 3ltr even-fire full up forced induction &/or sustained high rpm race use you really want to go to steel…

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I guess a question to Simonsays and Clee, given you have probably seen the most units between you, have you had experience of the water feed line from the heads down to the oil cooler going porous? Answers on a post card… I didn't want to touch this in case it was...

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John, are you going to keep the expansion joint where it is on this or remove it? Just a thought..

How’s it going anyway, any news?



Well if it makes you feel any better, I haven’t had time for much lately either, so progress has been very slow, and nudging on nil… hopefully over Christmas shut-down I can get my head down and get some traction on things. I did sort extending the tubes from the previous posts, cut’n’shunt.




Talking of news, how are you getting on Andrea, and Stunned as well with his bi-turbo DMC? Come on churp up... remember Blake 7...

Not many news lately, Martin.
Just worked a bit on the intake / cooler side, for making a better looking engine comparment for a delorean


I'm still having some problem making good maps with the Megasquirt. It runs, I have a wideband connected and the fuel is ok, but the trottle response is not enought good for me, it esitate and sputters in quick throttle changes, and sometimes seems it lost some rpms. I'm considering going back using the Safrane biturbo fenix ecu... i was successfull in making it run, putting the R25 v6t fenix 3b files inside, cause the original ecu for the safrane in locked and does not run without the code

Maybe in this winter days...

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Hi Andrea,

MS - what accel enrichment have you got, do you know what sort of algorithm it is using? Delta change on the throttle pot?

Where are you taking the intake pressure signal for your fuel pressure regulator? What throttle plate arrangement do you have, is it a twin or single?

Regards,
Martin

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Hi Andrea,

MS - what accel enrichment have you got, do you know what sort of algorithm it is using? Delta change on the throttle pot?

Where are you taking the intake pressure signal for your fuel pressure regulator? What throttle plate arrangement do you have, is it a twin or single?

Regards,
Martin

Hello Martin! The accell enrichement on the MS can be both from delta change on throttle pot or delta change on MAP, and can be a % of both.
But i'm quite sure the problem is not there, i tried varius value and the problem remain. Is difficult in particular when using the car slow on the road, on some conditions, in particular when on very light load, the engine sometimes makes "hits". I tried smoothing down the timing numers and curve, and it helped a bit, but still i have to find a final solution.
I have a dual throttle is it a 2 x 45mm. The fuel pressure regulator is the original safrane biturbo ones and is connected to the same place as original, to the middle of the intake.

Hi Andrea,

Reason I asked on the MS, is Eddie mentioned this, quote from his post on page 2 of this thread:

...then I,ll get on with the update & development off my 24vl. as you know from speaking with Chris I have changed from Renix to Megasquirt with wideband & the difference is unbelievable...the engine is so sensitive on the TB,s that it has to run on an O2 sensor...

So likely he had the issues you have been experiencing. I assume its fine when you accelerate very slowly and progressively?

Martin

Hi Andrea,

Reason I asked on the MS, is Eddie mentioned this, quote from his post on page 2 of this thread:

...then I,ll get on with the update & development off my 24vl. as you know from speaking with Chris I have changed from Renix to Megasquirt with wideband & the difference is unbelievable...the engine is so sensitive on the TB,s that it has to run on an O2 sensor...

So likely he had the issues you have been experiencing. I assume its fine when you accelerate very slowly and progressively?

Martin

Yes, slowly it runs nice, and the fuel mixture is always good enought.
Also, maybe this is something that depends most on the change to dual throttle i have now, but maybe i think is also something i can touch up with the timing: when accellerating even slowly, the MAP reading goes very quick to minus 20psi to zero, is quite difficult to modulate in between, and that's where i get the "hits" from the engine. Something like the turbo's are spinning too much, and early...or right, the throttle response is too much Should I try to lower the timing even more ?

The adaptronic's "throttle map prediction" function solved the issue of throttle response with that ECU.

The adaptronic's "throttle map prediction" function solved the issue of throttle response with that ECU.

Martin, can you explain in a bit more detail, this may be useful to Andrea.

Andrea, don't take timing out if you have this set for MBT, you don't want to be giving torque away for no good reason, especially if this is a competitive setup, well unless you want to race me joke drop me an email, it's in all our best interest to see our machines do the best they can...

The adaptronic's "throttle map prediction" function solved the issue of throttle response with that ECU.

http://dmctalk.org/archive/index.php/t-3736.html

I take it you mean the above Martin?

Andrea,
I had to do away with running my engine on MAP. & now run the setup on TPS. & wideband...the reason I found was the MAP could not keep up with the sudden changes in acceleration, in light or full throttle aplications, & hence the hesitations you may be having.
Eddie.