Mad idea or not ???

[clee]

I'm looking into how I can get more grunt out of the GTA on my very limited budget
I want to keep the PRV ..Peugeot Renault Volvo ....V6 .
I was looking at a A610 3l turbo lump but they are few and far between ,£4k new from Ren and the last one on Ebay went for almost as much
A Safrane or Laguna NA 3l is a possibility but there are a fair few issues in Turbo charging them ,9.1 compression ,inlet manifolds ,valves cams etc .etc ....
Some of the PRV engines are oddfire so they are out of the running .

Now then .....All the PRV cranks are the same main journals .The GTA turbo Z7U has a bore of 91 and a 63 stroke .The Espace/25 2.8 NA even fires are 91 and 73 .
Can I stroke it please 2.8l turbo ???
I have loads of GTA pistons and liners ,2 full sets newly ringed .I can design and get manufactured a few things with my contacts in the toolmaking trade at mates rates or even work it off .
I was thinking about making some custom rods out of Aluminium ...
I can get the high spec Aero stuff ,3D cad it up and get it machined etc but will need a bit of guidance with the main design concept .The block may need some cut-outs to miss the new rods .I'm going to measure and CAD up a local area to model it all up ...
Found these guys on the web ...as usual the Aussies are the ali experts ??
http://motorsport.bdg.com.au/conrod.html

Basic idea sound ? Or the ramblings of 'a little knowledge .................

[Andrew Cooke]

I wouldn't bother with aluminium rods, they end up bulky.

[clee]

Would that overly be an issue ?Are we talking bulky as a weight issue or need bulk for strength and they wont fit ? I could get them done in steel but the machining time trebles .
But the basic idea ? Is it a feasible route to go down ?
http://www.rrconnectingrods.com/aluminumrods.htm

[Scoff]

a guy called colin massarani from round my neck of the woods built a 2.8L (or was it 2.9L ?) V6 turbo for his DIY Turbo 2 replica. He's a member, search for massarani, he doesn't come online too often. He used a crank from 'X' and pistons from 'Y'.... I don't remember the details. He'd tell you what you need to know

[raj]

a guy called colin massarani from round my neck of the woods built a 2.8L (or was it 2.9L ?) V6 turbo for his DIY Turbo 2 replica. He's a member, search for massarani, he doesn't come online too often. He used a crank from 'X' and pistons from 'Y'.... I don't remember the details. He'd tell you what you need to know

i remember that guy from the old site, he never did post up any "detailed" pictures of his car though

[clee]

He's not in the Ms on here ....

What would be the major fundamental issues in doing something like that though ? Clearance ,balance ,compression ....No replacement for ...............
It would seem on face value a very tempting route given the lack of tuning knowledge and expense involved in the PRV world .Many do spout pearls of wisdom but no one knows anyone that's actually done it .Everything is bespoke in my little world

[Scoff]

he didn't really do much with the website but he knew a thing or 2 about renaults

[Trevhib]

He had a couple of awesome cars. Didn't he also get hold of a Safrane Bi-Turbo? I'm sure he did get round to putting pics on the site (though not of his 5).

[raj]

He had a couple of awesome cars. Didn't he also get hold of a Safrane Bi-Turbo? I'm sure he did get round to putting pics on the site (though not of his 5).

i think i remember this too! if im not mistaken it was a dark grey/tungyish colour and he actually bought the car from france..?

[Trevhib]

Aye.

[Trevhib]

Taken from Wiki: In 1994, Renault launched the high-performance 'Biturbo' version available in RXE and baccara finition. This model featured a twin-turbo, 262 hp (195 kW) evolution of the 3.0-liter V6 of alpine A610, developed with the assistance of German tuning firms Hartge and Irmscher, coupled with all wheel drive. However, it was only available with a manual transmission, as no automatic gearbox existed anywhere in the world for a transversely mounted engine of that horsepower with AWD. Given that automatic transmissions and V8 engines are strongly preferred in the price class where Biturbo competed, it is not surprising that less than 1000 Biturbos were sold.Production ended in September 1996.

Long Cours
In the same year, the French coachbuilder Heuliez presented the Long Cours, which was something like a station wagon version of the Safrane Biturbo in luxury Baccara trim.

Funny, as I was going to say, would it be possible to put an engine from one of these into the back of a GTA!

I'm off to look for pics of the Long Cours

[Trevhib]

Not much of a looker.

[Big Jim]

New poster! (less than 10 posts)

Not a mad idea at all. I am with Mr Cooke though, ally rods aren't really a good idea. The links given both allude to their problems. They have a short fatigue life (fine for a drag motor doing a couple of runs at most between rebuilds), they are terrible for galling on the big-end shuts and they spin bearings.
My experience with these engines goes back to '96 and a twin turbo 3l GTA I helped build (that had Mitsubishi turbos, used a modified Volvo inlet manifold and a pair of enormous charge coolers but I left there before it was finished so never found out how it went) and unfortunately is all a bit hazy, but I'm presuming the difference between the odd and even fire engines is the offset big-end journals? wouldn't it be easier to get an NA 3l lump, rebuild it with machined pistons for lower CR and use a different management system?
Otherwise just get stuck in, if you can get bits like rods made then anything is possible...

[clee]

Safrane Bi-turbos are rarer than a610 and more expensive .I know that the last two crated units went for a lot of dosh .One was complete with turbos,loom ,even gearbox .It's in Ireland being plonked in a GTA .The other short motor is in an underground car park in that there London ...............They were the last two in existence I believe ....


Now twin turbo is another route I'm looking into If you look on the bench you can see the Volvo plenum you mention .This route requires custome xhaust mani ,coolers ,throttle etc X2 of course .But I paid £25 for the Volvo plenum ,it needs injector ports putting in but it's been done before .......All this was pulled off a body kitted GTA just recently ,it never ran ......


If you can rack your brain Jim for any vague memories of what PRV bits you used I'd be very grateful
The 2.8NA oddfire ,yes offset journals .I think my Adaptronic will run the oddfire .That's another option ,with turbo heads 'cause of the sodium cooled valves and a set of custom pistons 9.5:1 on the 2.8 ...8.6:1 on the 2.5 turbo .

[clee]

What compression could I get away with say a bar of boost ?
The turbo is 8.6:1 the 2.8 is 9.5:1 .The turbo piston top finishes flush with the liner top ,but it has a 70mm x 3.8mil high dome that protrudes .Not got a NA piston so I dont know where it stops ,I'll have to get one with a 73 crank ....
If I made the rod 5 mill shorter we'd be in the same stop position but compressing another 65 cc So how much shorter do I need to go ?
Std 7ZU ..Big end to little crs is 146 ,small end to piston top is 43 ,crank is 63 throw so cr to deck is 220.5 .
What I'm looking to do is put in a crank that is 73 .
So it's either custom rods or pistons ????

[Trevhib]

Safrane Bi-turbos are rarer than a610 and more expensive .I know that the last two crated units went for a lot of dosh .One was complete with turbos,loom ,even gearbox .It's in Ireland being plonked in a GTA.

I bet they are rare! Mad that it's going in a GTA.

[Maka]

Not much of a looker.

i produced something very similar to that after a night of vindaloo abuse.

[markey b]

what was the renault 25 v6 turbo? think JP has one in his barn!

[clee]

Exactly the same as the GTA .Z7U only in those two cars .
Some of the 25's had lower comp ratio of 8:1 due to a 2mm lower crown height but feck knows where they are .I was going to look at machining some of the std crown off .I think that'll be all they did as I can't see them making a thicker section for just a few motors ????
I've sliced a piston to see and it shouldn't cause much of an issue if you see where the thin area is ...This will give me about 46cc more as well

[markey b]

has anyone got a pic of half a 5 piston... mine are pretty dished and that pic scared me!!!

[Markey Mark (BD)]

has anyone got a pic of half a 5 piston... mine are pretty dished and that pic scared me!!!

I got a knackered 5 one which i might cut in half just to see how much meat is left on there once there falt topped or dished

[markey b]

i've got a spare piston, but nothing to cut it with, unless a junior hacksaw is up to the job lol

[clee]

I did it with a normal hacksaw so a junior one should be fine on a iddy-biddy 5 piston
91 diameter ...about 7.5 mm thick at the radius to angle bit .....What's a 5s bore ??

[Scoff]

just to go back to the objective.... what is it ? if your after making more power then you aught to be looking at the cylinder head and not CC's. You can only make as much power as the cylinder head will support, which I dare say is achievable within sensible rpm's at the current capacity. The cylinder heads are not that wonderfull

If you're after making some better midrange then that's different

[clee]

I'm after more power .I don't want to lose too much low end torque .I have no beans to spend .
Given the RR result ,the next stage is the 60trim turbo ,330cc injectors and 250 is possible on those rollers ???
It's very difficult to get any info on the Europa Cup GTA ...they're supposed to be 300 with not much different to a std Z7U lump ....but .......
Head work is wot per pot ?

[Big Jim]

New poster! (less than 10 posts)

just to go back to the objective.... what is it ? if your after making more power then you aught to be looking at the cylinder head and not CC's. You can only make as much power as the cylinder head will support, which I dare say is achievable within sensible rpm's at the current capacity. The cylinder heads are not that wonderfull

If you're after making some better midrange then that's different

True for NA motors, much less so for supercharged ones. Why do you think they supercharged the Mini Cooper S? The base chrysler engine was so rubbish the only way to get the performance they wanted was to blow it!!!

Back to your earlier question clee, 9:1 should be fine on a bar of boost. I'm sure the easiest way would be to use all the NA bits and machine about 1mm off the crown. Know its boring but you probably don't need any custom bits for this level of tune.

[Big Jim]

New poster! (less than 10 posts)

And as an aside, please promise me you're not going to use that exhaust manifold.....

[Scoff]

New poster! (less than 10 posts)



True for NA motors, much less so for supercharged ones. Why do you think they supercharged the Mini Cooper S? The base chrysler engine was so rubbish the only way to get the performance they wanted was to blow it!!!

yeah, but that isn't really what I ment jim.

his power potential is the same regardless of cc's. If the cylinder head and camshafts havn't changed then it's potential to breath hasn't increased any. this is true of an FI engine too. it's ability to breath will ofcourse increase but only if he hasn't reached the limit of the cylinder head.

In the case of the GTA it's widely accepted that the cylinder heads are pretty crap. there is more potential in lee's engine which he can extract without extra cc's. I know his car, I mapped it, I know that when he fits his larger injectors and we run more boost that he'll make "some" more power but it will rapidly get to a point where more boost doesn't yeild extra power - that'll be the cylinder head and camshafts becoming the bottle neck. At this point more CC's won't help, and that was my point really.

[clee]

The manifolds are the biggest restriction .Heads are ****e .
I'm up for any suggestions ,advice
I think we'll run out of grunt at the next level as Scoff says .But surely a 2.5l v6 should be capable of more .
I want to get more power but spend my money in the right place first time
I think I've got a 3l crank sourced ,one of the less vocal Alpine guys has done some research ,mocked up a bottom end etc .He has some bits and pieces ,ideas .
3l heads might be OK ..My sort of price as well .....barter the parts bin

[Ian S]

The 46cc is of course only the chamber increase or total volume increase. The swept area remains the same. So it stays as a 2.5 litre.

The 5GTT piston crown apparently is 13mm thick so there's plenty of metal left after taking off a couple of mm.

The 5GTT is 76mm bore IIRC which I may not.

[Trevhib]

.But surely a 2.5l v6 should be capable of more .

Don't forget the 2.8 inj engine in the Capri back in the day (1988), made a whopping 150bhp. Less than my old 1.6 CRX Vtec produced in 1991. Lol.

[Ian S]

Surely quite a bit more torque though and where it's wanted.

Power is just torque x revs.

So if it won't rev it won't make so much power. But might still pull like a train at UK legal speeds.

[clee]

Don't forget the 2.8 inj engine in the Capri back in the day (1988), made a whopping 150bhp. Less than my old 1.6 CRX Vtec produced in 1991. Lol.

I had one back in the day Then I had a TVR wedge with the same lump ...I know which one went better

[Trevhib]

So if it won't rev it won't make so much power. But might still pull like a train at UK legal speeds.

What, all the way to 30

Sorry Ian, I'm just being facetious. What you assert about torque is spot on.

[markey b]

dunno if anyone wants to move this post... but i got a c1j piston cut down today

[Scoff]

lee, it might be interesting if you could collect the data of your own cam's plus any of the NA cam's you can find, it might be that some of the NA cam's are be better suited once you get the big turbo back on.

[clee]

That's the problem .....finding the data . I sold a set of cams that were supposedly better for my needs ages ago before I knew owt ...2.8l espace or 25
I can't remember but I did measure them at the time very roughly .David G had them off me and sold them on .I'll do some digging .

[Scoff]

some of the time the printed data needs to be taken with a pinch of salt anyway since they probably won't tell you how they've measured it!

how about gather up some camshafts from likely donor engines as and when you come across them cheaply then meaure them in a spare block like andy did with the GTT camshafts.

[clee]

I did write it down somewhere ....Argggh I hate it when that happens
They had far more lift I think .

[Scoff]

I did write it down somewhere ....Argggh I hate it when that happens
They had far more lift I think .

the standard factory cams will be pretty mild things, they're designed to work with a poky little turbo. some NA cams might be a cheap winner.

[Big Jim]

Hey, I think scoff and I agree on something. Seriously though take a look at the 3l cams, they've probably got the most aggressive profile (being from the largest engine and it needing to breathe through crap heads...). Unless, of course, there was a particularly sporty version.

I'm not doing a sales job here but getting your heads cleaned up and cams reprofiled is not going to break the bank, if they really are that much of a bottleneck it would make a big difference.

I think I should clear up that when I talk about power I generally mean an engines performance within its useable envelope. The peak number is nice to have and gives you a high top speed potential, but not much else. Know I'm not being completely semantically correct on this one, but there really is no substitute for cubes.

[Scoff]

3l cams could be the winner then

[clee]

I've got two sets of skimmed heads with cams and another complete Z7U .So plenty there to experiment with .I've got a N/A 3l block and crank coming in the post did a swap from the parts bin
Volvo B280E ...highest lift and longest duration std cam .I want more power but for track use ,not strip .
How much is not much Jim ? PM me a rough idea .

The Venturi 260 is supposedly a 2.8l 7ZU with a 73 crank and custom pistons ....300ftlbs and 260 bhp @ a bar . I need to get this confirmed .

[clee]

Found some data on the B28 Volvo cams I need to measure the std GTA lift but the timing is thus on the Z7U cam .
Inlet open 8 btdc
Inlet closes 40 abdc
Ex Open 40 bbdc
Ex closes 8 atdc

Volvo Cam ( it's odd fire but I think the lift will be similar to the B280E which is even )_ I think

cam data B28 STD.doc

[Andrew Cooke]

Found some data on the B28 Volvo cams I need to measure the std GTA lift but the timing is thus on the Z7U cam .
Inlet open 8 btdc
Inlet closes 40 abdc
Ex Open 40 bbdc
Ex closes 8 atdc

Volvo Cam ( it's odd fire but I think the lift will be similar to the B280E which is even )_ I think

cam data B28 STD.doc

take that data and throw it in the bin, it's meaningless. Measure everything, trust noone, they're all liars

[clee]

Yes,so I've been told
If I measure the lift on my std cams can I trust myself
I have been known to feck things up now and then

[Andrew Cooke]

Yes,so I've been told
If I measure the lift on my std cams can I trust myself
I have been known to feck things up now and then

actually, what you can see from the Volvo data is that the LSA is 106deg (I hope, I'm rushing here...), and it's timed straight up.

If you can't trust yourself put all your toys in a big box and stick them on Ebay

[clee]

I did work out out what LSA meant before I googled it

How you deduce the angle from the figures though escapes me
Must get boring measuring all those C1J cams Andy ? How about measuring some nice big v6 units to break the monotony

http://www.popularhotrodding.com/eng...ion_angle.html

[Andrew Cooke]

I did work out out what LSA meant before I googled it

How you deduce the angle from the figures though escapes me
Must get boring measuring all those C1J cams Andy ? How about measuring some nice big v6 units to break the monotony

http://www.popularhotrodding.com/eng...ion_angle.html

it gets a bit tedious, I've done an awful lot of them now
The main thing is to be consistent in your method, I think yours is OHC, I've done some EVO cams, and they were an arse as I had to modify it to solid tappet and shim the tappets. If you have adjustable tappets you just need to fit an inlet and exhaust valve with soft springs then plot the valve movement.

[clee]

I just need to get a cam angle dial knocked up .I was going to put a clock on the valve top and watch when it moves But I hadn't thought to put a softer spring in
Would this be accurate enough ?
I have already jigged a head up after my valve clash issue ........