PRV V6 Are the even and oddfire conrods the same?

Aln

Aln

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I am looking into the possibility of putting some Chinese Carillo copy conrods in an evenfire 2975cc engine I will eventually build. Many years ago John Lane in the US put plenty of boost into an evenfire PRV resulting in good power and bent conrods. Detonation perhaps? He said that with aftermarket conrods he had no trouble.

My engine block is from an evenfire Volvo760 2850cc which I will be using Renault Alpine GTA turbo heads and manifolding on, using the Volvo cams and a set of 93mm Alpine A610 pistons with the Volvo crank which has 10mm more stroke than the original GTA Turbo. The way the Chinese ones are advertised it makes out the even and odd fire are the same.

I don't know if these are Chinese, an Australian company, but a whole lot more expensive than the Chinese ones. https://ppmracing.com.au/product/renault-prv-v6-3-0l-h-beam-connecting-rods/

These are Chinese. https://www.alibaba.com/product-det...offerlist.normal_offer.d_title.e3f76837BLMGfw

Different heading. https://www.alibaba.com/product-det...offerlist.normal_offer.d_title.e3f76837BLMGfw

Says min 18 but seems to accept 6 at more cost. $429 USD including freight for 1 set.
 
Can I ask what’s your power level your wanting to achieve ?
Yes the same, not sure about the 2,5s though, I’d suggest changing the pistons, the PRVS suffer ring land issues with boost , you get then made bigger and use a much common later style rings.

My 2975cc Pug 505 V6turbo has 226kw/303hp atw on 12psi, everything is standard and is not at its full potential due to weak gearbox, pistons are the next thing to get for me. with a good programmable ecu and tuner the standard rods will be no problem,

A club member has run 24psi on track with 2975cc alpine turbo pistons and rods and produces 400hp,


Ben

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Aln said:
I am looking into the possibility of putting some Chinese Carillo copy conrods in an evenfire 2975cc engine I will eventually build. Many years ago John Lane in the US put plenty of boost into an evenfire PRV resulting in good power and bent conrods. Detonation perhaps? He said that with aftermarket conrods he had no trouble.

Even fire and odd fire rods are completely different. Both the big end and gudgeon are different sizes. The PPM rods appear to be correct for the even fire.
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PPM are definitely Chinese. If you want Australian made then look up Argo.
 

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Can I ask what’s your power level your wanting to achieve ?
Yes the same, not sure about the 2,5s though, I’d suggest changing the pistons, the PRVS suffer ring land issues with boost , you get then made bigger and use a much common later style rings.

I expect to be looking for 330-350Hp at the flywheel, so basically the same as you have. The new piston and sleeve kit I have is Alpine A610 which are said to have 250hp at the flywheel and the A610 is boosted standard. 8.6 to 1? The conrods between the Alpine 2455 and Volvo 2850 evenfire are the same, don't know about the A610. I will have to compare the pistons to see that the gudgeon pin is 5mm higher in the A610 compared to the 2455, to be able to use the same rods. I can also compare the Volvo 2850 pistons with the A610 which should have the same pin height.

My 2975cc Pug 505 V6turbo has 226kw/303hp atw on 12psi, everything is standard and is not at its full potential due to weak gearbox, pistons are the next thing to get for me. with a good programmable ecu and tuner the standard rods will be no problem,

I am surprised with your output at 12psi, my belief being they seem to be a "lazy" engine although a few seem to have made them go. My original standard Alpine GTA Turbo is 12psi 2455, with tiny cams and turbo and makes 200hp. I was thinking I would need 20psi to reach that 330+ level. I will be using aftermarket ECU, either one of my old M4 Motecs or M48, or probably a newer Motec or Haltech, not that I will need many of the outputs of the newer ECUs.

A club member has run 24psi on track with 2975cc alpine turbo pistons and rods and produces 400hp,

My new turbo is a Garrett GT3071R with a smallish .64 exhaust housing. The original 2455 only has a .38 housing, spools up quickly but starts to reduce boost at 5000rpm, running out of breath. Feels very torquey in normal driving.

UN1 gearbox limit (Alpine and others) is around 350Hp I am told, but can be made better/stronger with serious money. They were often used in GT40 replicas with 5L engines, but can fail in 5th gear at full noise as the gears are of the outrigger type.
 
W
Aln said:
Can I ask what’s your power level your wanting to achieve ?
Yes the same, not sure about the 2,5s though, I’d suggest changing the pistons, the PRVS suffer ring land issues with boost , you get then made bigger and use a much common later style rings.

I expect to be looking for 330-350Hp at the flywheel, so basically the same as you have. The new piston and sleeve kit I have is Alpine A610 which are said to have 250hp at the flywheel and the A610 is boosted standard. 8.6 to 1? The conrods between the Alpine 2455 and Volvo 2850 evenfire are the same, don't know about the A610. I will have to compare the pistons to see that the gudgeon pin is 5mm higher in the A610 compared to the 2455, to be able to use the same rods. I can also compare the Volvo 2850 pistons with the A610 which should have the same pin height.

My 2975cc Pug 505 V6turbo has 226kw/303hp atw on 12psi, everything is standard and is not at its full potential due to weak gearbox, pistons are the next thing to get for me. with a good programmable ecu and tuner the standard rods will be no problem,

I am surprised with your output at 12psi, my belief being they seem to be a "lazy" engine although a few seem to have made them go. My original standard Alpine GTA Turbo is 12psi 2455, with tiny cams and turbo and makes 200hp. I was thinking I would need 20psi to reach that 330+ level. I will be using aftermarket ECU, either one of my old M4 Motecs or M48, or probably a newer Motec or Haltech, not that I will need many of the outputs of the newer ECUs.

A club member has run 24psi on track with 2975cc alpine turbo pistons and rods and produces 400hp,

My new turbo is a Garrett GT3071R with a smallish .64 exhaust housing. The original 2455 only has a .38 housing, spools up quickly but starts to reduce boost at 5000rpm, running out of breath. Feels very torquey in normal driving.

UN1 gearbox limit (Alpine and others) is around 350Hp I am told, but can be made better/stronger with serious money. They were often used in GT40 replicas with 5L engines, but can fail in 5th gear at full noise as the gears are of the outrigger type.
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my turbo is a max speeding rods 30/76 with .64 housing, motec m48 ecu.
Makes power all the way to 7000rpm or more if I let it but it’s all standard and limiter is 5800rpm. Boost starts at 2800rpm.
If I put 15psi into it I’ll see 300rw kw. But it’s only standard. Has 600cc injectors on 98 fuel.
Camshafts and lower compression ratio I’ll see over 300 if I can get a gearbox to handle it.
A good big breathing exhaust is a must, big dump pipe is a secret in the recipe.

You’d be surprised what an efficient turbo does, but I have a water to air intercooler which is small but is very efficient, 400HP rated.

Before I put the big turbo on I had a VL turbo T3. Lost power at 5300rpm. Had 200hp 515nm of torque.

I had a 2.6 lpg turbo intercooled with a VL turbo t3 and it had 210 hp on 15psi not reliable, 180hp reliable.

I’ve lost a lot of torque but the power up high is worth it. I’ve gained 100hp lost 200nm and 3psi and 10degrees less timing.

The 30/76 is too big really if I had a big intercooler it would be laggy., for a 3litre ideally need something slightly smaller. To keep response and torque. torque also bends standard bottom end. But the 30/76 is a 500HP turbo.
 
I started and stopped this engine project about 12 years ago, so all that I am saying now is from memory, with all the parts living at my Mums, and for shame I have not sighted any of the pieces in many years. I will though be retiring in two weeks and although the GTA is not top of my current car/bike work list, the engine should be assembled this year.

The Volvo B280F camshafts are much larger than the original GTA Turbo. From a memory guess 9.2mm to 6.64mm valve lift with longer duration also on the Volvo N/A cams. Also the Volvo valves are larger, with these being fitted to the GTA Turbo heads which have a nicer port shape. Porting was just a cleanup and blending. Interestingly the original Turbo valve seats were at 30 degrees rather than the standard 45.

I have some new larger injectors, don't remember what size, but for a LS powered Holden I think. Might only be 380cc. Sounds small.
I can wind up the fuel pressure a little to gain a bit more capacity, but will see how it goes. The exhaust has already been upgraded to 3" with a separate wastegate outlet that runs into the main pipe downstream, and has a 200 cell metal cat and large oval resonator with a single outlet rather than the original two.

The 3071R ball bearing turbo has been run for a while on the standard car, quite a bit laggier than the original, with boost a bit like yours at 2800rpm, but a flat boost line to the 6100rpm standard cut out compared to the original. Given the capacity will be going from 2455 to 2975 and better breathing I hope the boost starts to come on at maybe 2300, but it will be what it is. I have a tubular water to air intercooler to fit and the standard air to air intercooler will still be in place.
 
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A little shot of wet nitrous will get rid of the lag.😁
I know ZEX used to do kit just for this purpose, adjustable bhp and boost cut. You only need a quick hit in first as the engine stays in boost once you're on the boil.
I know nitrous isn't strictly legal, but with a little imagination it's easy to hide, or so I've heard.😉
 
I know nitrous isn't strictly legal, but with a little imagination it's easy to hide, or so I've heard.

Back when I was a racecar Scrutineer, occasionally we would find nitrous on a vehicle. It was illegal in all classes. Ingenious hiding places and ways of making it operate. Normally in production type same series cars that were only looking for say a 10 or 15 Hp. Run the carb rich and introduce the nitrous via the vacuum system.

One car required the cigarette lighter to be pushed in along with the horn button pressed to power the solenoid. Another had an accident where it hit the guard rail and tore off the LH front guard exposing the bottle.

I don't think whatever lag the GTA will have will be much of a worry. The motors tend to be torquey rather than big power units generally, but they certainly have been raced and made to go well by some.
 
Aln said:
I know nitrous isn't strictly legal, but with a little imagination it's easy to hide, or so I've heard.

Back when I was a racecar Scrutineer, occasionally we would find nitrous on a vehicle. It was illegal in all classes. Ingenious hiding places and ways of making it operate. Normally in production type same series cars that were only looking for say a 10 or 15 Hp. Run the carb rich and introduce the nitrous via the vacuum system.

One car required the cigarette lighter to be pushed in along with the horn button pressed to power the solenoid. Another had an accident where it hit the guard rail and tore off the LH front guard exposing the bottle.

I don't think whatever lag the GTA will have will be much of a worry. The motors tend to be torquey rather than big power units generally, but they certainly have been raced and made to go well by some.
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Ok, let me know how you go, very interested to see how it goes.
 
On a larger "street" car you can gut the heater box and fit a 5lb bottle in there. You tap a couple of 5/8" BSP holes in the V8's valley cover, screw in some 3/4" hose tails and run the fuel line, nitrous line and the solenoid wires down the insides of some 3/4" heater hoses. The solenoids and nozzle are mounted under the valley cover. You run a scuttle mount fuel pressure gauge (supplied by a 1/4" line) inside a neat little aerodynamic cowl, tee off the fuel supply line underneath the cowl, and run a fuel line down through the plenum and into the heater box. You activate the the nitrous with the heater's fan switch.
Quite a number of scrutineers have failed to find such a system, or so I've heard.🤫

I had an American book on nitrous oxide tuning many moons ago, back when Marvin Miller and 10,000 RPM systems were de rigueur.
There was a tale in it of a US stock car racer that always seemed to have an extra burst of speed available on the last corner of the last lap. The vehicle was checked many times and they could never find a N2O bottle. These were the days when they raced in overalls. He eventually got caught when the scrutineers heard a hissing sound coming from the driver. Turned out he carried a 15oz bottle of N20 in his baggy overalls with a quick release fitting on it, but on this day he hadn't quite turned the valve off fully.🤦‍♂️
The book didn't elaborate on the rest of the system, as to how he concealed it, or whether it was wet or dry.

I've only ever run wet systems. I love N2O, there's nothing else like it for adding power.
I didn't try to conceal the system on my V8 Rover, the twin plates and solenoids were about 8 inches above the bonnet and the bottle was bolted to the front passenger floor.🤣
A 100 HP shot into the blower on that vehicle took 8/10ths off the 60 foot time.
Only problem with N2O is the gas is a bit expensive.

20240426_213635.jpg
 
well.... a guy, he figued out a way to liven up the old PRV powered cars :)


What does this appeal to me so much :D
 
An Englishman fitted an LS to GTA some years ago and continues to play with GTAs in various guises.

Ultimately the UN1 gearbox although very strong by Renault standards it is probably limited to handling about 350Hp.

I will be staying PRV even though there are many more modern engines that easily out perform it, with better fuel economy.
 
Aln said:
An Englishman fitted an LS to GTA some years ago and continues to play with GTAs in various guises.

Ultimately the UN1 gearbox although very strong by Renault standards it is probably limited to handling about 350Hp.

I will be staying PRV even though there are many more modern engines that easily out perform it, with better fuel economy.
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I think it states somewhere he's used a porsche 6spd gearbox (which makes sense, the configuration would be right for a Porsche ). Its interesting to see the grabbing at the steering wheel with the gear changes. It must be a huge handful to keep in a straight line ?

I'd probably join motortrend just to watch that show, but its geoblocked to australia, and I can't be bothered with VPNs etc. .... :)
 
Aln said:
An Englishman fitted an LS to GTA some years ago and continues to play with GTAs in various guises.

Ultimately the UN1 gearbox although very strong by Renault standards it is probably limited to handling about 350Hp.

I will be staying PRV even though there are many more modern engines that easily out perform it, with better fuel economy.
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I Agree same here, the fact an engine made in the 70-80s pushing decent power,

I’ve got a plan to repower it eventually but the v6t will go into a road car, Long live the PRV
 
In relation to the original question one obvious difference is that in oddfire motors the gudgeons are pressfit into the little end. In evenfires the little end of the conrod has a bearing in it and so the floating gudgeon is held in by circlips.
 
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