Tuning an original 5 cup for racing in Toyo Tires Saloons

New poster! (less than 10 posts)

Hi,

I'd just thought id post on here and try and pick some brains.. also posted on renault5gtturbo forum, guys on there have been pretty helpful :)

I've been rebuilding one of the original cup cars (radbourne 003) for the Toyo Tires saloon car championships next year. Fairly familiar with building race engines (and cars) as have been doing it for a while.

Due to the technical regulations i'm constrained from going down a traditional tuning route with the 5. In short I have to stick with the standard Turbo (T2 with the addition of a 360 thrust bearing - tubby has to be inspected and sealed so no chance at ALL of a sneaky hybrid) and standard management (though the advance trick will be fine, and standard fuel delivery (hence the grp A carb is ok, but I cant go standalone management and injection :rolleyes:

My car runs around the 160bhp mark at the moment, but I want more! http://www.renault5gtturbo.com/forum...on_biggrin.gif

I know that the works Renault 11 rally cars (same engine and turbo) used to run close on 180bhp with a fairly standard engine but grp A cam.

From what I understand this is about the max air/bhp the turbo can flow and headwork and larger inlet valves will make little if not any extra power. Also its looking like a 285 profile cam could really hurt performance running a standard T2 as its moving the power band of the engine up, whereas the T2's powerband is lower down and is running out of 'puff' by 6'000-7'000 rpm if not a bit before.

Have spoken to Cat Cams who pretty much confirmed that, and they are looking into doing me a custom profile to compliment the power curve that the T2 produces.. does this sound about right?

Originally I was considering putting together a completely balanced bottom end, together with hot cam, massively worked head, with work done to the throats, valve guides, enlarged inlets and bigger inlet valves, uprated springs etc, etc.. tubular manifold, tubular turbo back outlet pipe.. In short the type of engine you would build if you were considering putting a hybrid on for serious bhp. From experience I know that putting a really decent, worked head on a car should give around a 20% power gain, but there seems to be an upper power celing with the standard T2 of about 175-180bhp, so this is looking like throwing good money away?

Obviously every extra hp I can get counts, but don't want to spend £800-900 on a head and £££ on other bits and peices if its not going to do get me any further than the 180bhp barrier so its now looking like a Quaife ATB diff is going to be a better investment..

If anyone has any experience or hints on what to look into to squeeze more hp out id really appreciate the help.;)

Also has anyone flow tested the heads that GT Tuning and KTec produce, as they seem to be half the price of the same head that Prima produces (i've seem the flow graphs for the Prima head as well and is a seriously well done head..) but again, am always up for saving £££ if the product is good!

Cheers

Oli

what boost pressure are you going to be running, and are you allowed to use a chargecooler... or is this not suitable due to the length of the races...?

New poster! (less than 10 posts)

It's still set there or thereabouts at what it used to run when it raced, off the top of my head that's 16psi at the carb (though I could be wrong.. as i've not put a accurate gauge on it yet)

Charge coolers are not allowed unless fitted as standard, I can go up in size intercooler wise to the equivalent area of the sierra cossie 2wd standard one, which isn't much different to the standard one.

Water injection is allowed, however, from looking at this year the races range from 20mins to half an hour so the amount of water needed would add quite a bit of weight..

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Originally Posted by olidaviesuk

New poster! (less than 10 posts)

It's still set there or thereabouts at what it used to run when it raced, off the top of my head that's 16psi at the carb (though I could be wrong.. as i've not put a accurate gauge on it yet)

Charge coolers are not allowed unless fitted as standard, I can go up in size intercooler wise to the equivalent area of the sierra cossie 2wd standard one, which isn't much different to the standard one.

Water injection is allowed, however, from looking at this year the races range from 20mins to half an hour so the amount of water needed would add quite a bit of weight..

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ok, so your boost is pretty much running on the limit of the turbo.. i'd have thought the best way of getting £/bhp in your situation is to get an air charge temp gauge in the carb top... fit a big FMIC, and wind the boost up to find the most you can run without the temp's getting too high. could be a bit of trial and error in this, but certainly an area to look at.

New poster! (less than 10 posts)

Thanks for that, :) id looked into keeping the charge as cool as possible (for reliability) by fitting a water spray to the standard intercooler. However, hadn't though of the potential for getting extra horses by going front mount, im assuming essentially what id be doing is running the turbo past the point where the charged air is at a sensible temp and using the FMIC to bring the charge back down to a sensible temperature - then keeping an eye on the charge temp.. If that works i've got a handy mate with electronics who could knock up a temp switch to turn on/off a water spray automatically as soon as the charge reaches a certain temp.. which would reduce the water id have to carry.

Would a tubular manifold and very hiflow elbow (striaght from the turbo back, getting rid of that nasty piece of casting) suitibly wrapped in exhaust wrap help as well, as would get the exhaust gas out and away quicker than the standard stuff and help keep the exhaust temp down (bar the restriction of the turbo of course?) as im assuming that its the restriction of the exhaust turbine (rather than the compressor wheel) thats causing the extra heat to be generated?

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Originally Posted by GordonB

ok, so your boost is pretty much running on the limit of the turbo.. i'd have thought the best way of getting £/bhp in your situation is to get an air charge temp gauge in the carb top... fit a big FMIC, and wind the boost up to find the most you can run without the temp's getting too high. could be a bit of trial and error in this, but certainly an area to look at.

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Don't bother with tubular manifold, proven to give hardly any gain, if any at all. Most if not all of the high powered gtt's use the std cast exhaust manifold. From what i have read i/c water sprays do jack for charge temps on an intercooler that ain't up to the job to start with.

If your stuck with the std t2, might aswell keep the original sized intercooler. Any more than 1 bar boost with a t2 & the compressor will be out of its efficiency zone, blowing out hot air.

Id keep the standard carb, jet it up properly, the 'grp a' tuner carbs are a waste of money. Dial in some ign advance.

For cam I'd use a Piper 270, or standard, nothing else. Look at decent valve springs, with a small turbo you want to make sure the exhaust valves stay closed. I wouldn't bother with water sprays or injection, they seem to be more trouble than they're worth. Make life easy for your turbo, good cold airbox that's seeing pressure not vac, and good flow from the turbo back.

Most head and manifold work for the 5 is shiney shite, chose your porter with care.

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Originally Posted by olidaviesuk

Also has anyone flow tested the heads that GT Tuning and KTec produce, as they seem to be half the price of the same head that Prima produces (i've seem the flow graphs for the Prima head as well and is a seriously well done head..) but again, am always up for saving £££ if the product is good!

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Half the price, but still the same sh1te quality. I doubt you'd gain the power claims you say with decent headwork, as at that level of boost the head/valves/manifold aren't gonna be that much of a restriction. The bottleneck problem lies within the carb (venturi). Never a bad thing to match the manifolds to the head though.

Most, if not all, tuner grp A carbs will probably fuel reasonably ok on full boost, but will over-fuel miserably in all other conditions. Buy yourself a wideband probe & meter, read the carb article, and previous threads on here about carb mod's, and re-jet the carb yourself.

Remove the choke flap for better flow through the carb. Likewise, you can also remove/cut off one of the bars that 'holds' the throttle plate in situ, and use smaller length pan-head (or countersunk) screws.

O.E intercooler is fine at 1bar boost, but you could remove the thermostat gubbins for a smoother air-flow. If possible, fit some ducting/panels that'll divert/force the ambient air through the intercooler core.

A cam may help, but you won't want anything as hot as a 285. The std T2 turbo is gonna be wheezing out of breath around 6k, so no point pushing the power-band upto that rpm region or higher. Something like a 270 is probably gonna be more ideal.

If you're allowed to run higher octane fuel, for sure wind on the ignition advance.

Are you allowed to increase the c/r? If so, and given the low ish boost levels you'd be running, upping the c/r should give you some power gains...if you can avoid running into detonation...which shouldn't be an issue if you are allowed to run higher octane fuel.

Not sure if you mentioned about suspension, but some of the Super Coupe Cup series cars ran Koni shocks. Quite a few of the track lads, myself included, ran/run them these days as well - V good setup for not much outlay, but I'm guessing you'd want stiffer springs as opposed to the soft ish ones that come with the 'road use' kit.

Personnally id stay clear of the prima heads :crap:

the 1 i had was terrible :disagree:

New poster! (less than 10 posts)

The power gains im quoting come from my experience with vauxhall normally aspirated engines, hence, moving into tuning a boosted engine is throwing my knowledge out the window a bit and starting again, however, peeps on here are being really helpful, which is appreciated...

20% can be achievable with the right person doing the porting on a na engine, with proper flow testing on a bench, however, I can't afford a head from the place that did my last race engine as the price was (lets just say not cheap) however, was proven hp, with a dyno before and after by an independent place..

The matching is a good point - the engine that i'm working with is a blueprinted lump by mark fish, and the car is the very late cup spec (and won many of the final races included the 2004 aniversary race. All the cup spec engine/intercooler/carbs mods have already been done (by Mark when it was raced) which is whats proving to be frustrating as the car will be competitive in the state of tune its already in, however, if I can squeeze just that little bit more out of it (and it really is only 15/20 bhp or so) then it stands a good chance of being not only a class winner, but outright race winner.

Raising the compression - like the sound of this, however, am restricted to pump fuel, hence, optimax 99, is this going to be enough to stop det? A 270 cam was exactly what cat have come back with, which is great, nice to have info confirmed by multiple sources! :) would they be a prefered supplier or is someone like piper a better bet? have used cat before and usually spot on with what they say..

Its got the koni's on already, have organised getting them revalved to sort the toyos as opposed to the dunlop slicks, however, the front does need to come down a bit as their is room for improvement on the cup springs, don't suppose you know what spring rate / height they used to run in the super coupe days as I was going to get faulkners to knock me up a set of custom springs.. does 270lb 5" springs sound right?

I'm not knocking the gains possible with working a n.a head/engine, as that's a different kettle of fish. Given the air is 'pushed' into the engine on forced induction motors though, the power gain won't ever be as good.

It's been carried out many a time on c1j heads - The gain simply isn't worth the expense, and even more so at the level of power you'd be running.

Might wanna check the throttle plate - Pretty sure Mark never modified that. Bonus if you're also running the 25.5mm works venturi though, as that's a smoother, longer jobby compared to the o.e Solex venturi.

Might be worth raising the compression a touch. It's 7.9:1 as standard, and a few people have successfully raised the c/r to 8+ without inducing detonation. There's a few ways around det' if you do encounter it though.

The Cup cars were always speedboat-like with their suspension. Seemed to work well enough on track for them back in the day, so maybe try it first before worrying about lowering it/changing the spring rate.

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Originally Posted by olidaviesuk

New poster! (less than 10 posts)
A 270 cam was exactly what cat have come back with, which is great, nice to have info confirmed by multiple sources! :) would they be a prefered supplier or is someone like piper a better bet? have used cat before and usually spot on with what they say..

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a catcam 270 is not the same as a Piper 270 ask them both what the LATDC figure is before you make a decision. What specs did Catcam give you?

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Originally Posted by olidaviesuk

Have spoken to Cat Cams who pretty much confirmed that, and they are looking into doing me a custom profile to compliment the power curve that the T2 produces.. does this sound about right?

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would be interesting to see what they reckon they can do.... but you may be pissing away a load of money on a custom cam. :scared:

Like Mart said, get wideband afr logging going and get the carb setup properly.

Also, are you running the standard devil exhaust on there? Might be a few extra ponies by going up to a 2.5" downpipe and exhaust...

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Originally Posted by olidaviesuk

New poster! (less than 10 posts)

The power gains im quoting come from my experience with vauxhall normally aspirated engines, hence, moving into tuning a boosted engine is throwing my knowledge out the window a bit and starting again, however, peeps on here are being really helpful, which is appreciated...

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If it can been done with a GTT then it probably has been done with a GTT (with the odd Matt C like exception). Most of the people posting on this thread really have seen it all. They know their apples. You'd get a lot less useful information from a tuner for £25. ;)

btw, get some pics up! :D

A friend of mine raced his 5 in that championship a few years back. Like most racing, they all cheat!

If the rules are the same as they were a few years back (guess they are) you can basically do what you want. None of the turbo car's ran standard turbo's and they all ran water injection. I think they said something like you can run the turbo off any other car in the manufacturers range or something?! Can't remember now... I'll go take a look at them at some point! Providing you don't take the piss and no one complains you'll be ok.

You'll need quite a bit of poke to be competative too, at least 200! The 205's that used to head the field were running 230-240bhp and were superbly developed. We're talking £6k+ engines! Towards the end of the season, they'd be smoking, desperate for a rebuild! There used to be a lad in a Mitsubishi Starion turbo - he waxed it up to 30psi boost for qualifying and usually only did one hot lap.

My mates car ran a Piper 292 cam, big T28 turbo at I think 23ish psi, big downpipe/side exit, cossie 4x4 cooler, water injection, headwork etc. Just the usual stuff. Pagid race pads are enough to stop the car ok, standard calipers. That cam probably wasn't the best choice for reliability at that boost level tho... although it was massively fast ;) Probably top 5 pace.

To be perfectly honest, unless you're extreeeeemly good with the spanners and spend quite a bit of time testing and you dont want to run towards the rear of the mid field.... its probably not the best car to run in that championship.

That said, it has been a good year or so since I saw the Toyo's race.

Right, I'm off to the pub to watch us get battered by ze Germans!

New poster! (less than 10 posts)

Still waiting on Cat to get back to me, might just go with the Piper 270 if they take any longer :crap:

Pics to come this weekend, still waiting on the photographer to get back to me with pics of the test day..

Yup is the standard devil side exit, main worry for me is noise testing, as cadwell and castle combe in paticular are really hot on it, and not exactly a lot of room to fit a silencer that'll actually do much with the noise under there, the devil system is borderline at brands and the limit is 105dB there :rolleyes:

Forum is really helpful, def worth the £25, with here and the renaultsport works manual should be sorted :cool:

Dave - fortunatly not the same championship any more :ashamed:, was a split and branch off from that and khumo saloons about two years ago.. the one your mate used to race in is now CSCC which is still toyo saloons as is the one im in (but are now two championships with very different regs :agree:) have seen those 205gti's you're talking about go - silly quick, funnily enough almost bought an ex works rover tomcat to race in that series before I got the 5...

Right off to get the spanners out, and a bit more testing methinks... :)

One last thing - was considering getting the car setup on a rolling road, as there isn't a large stretch of private road near me (other than brands), and haven't got a wideband.. I usually use track n' road in essex (the two Steve's), however, know they won't have the jets for the 5 in stock so was considering taking it up to bb, obviously people have 'differing' views on tuners, but are they competent to correctly set the fueling up etc..

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Originally Posted by olidaviesuk

Yup is the standard devil side exit, main worry for me is noise testing, as cadwell and castle combe in paticular are really hot on it, and not exactly a lot of room to fit a silencer that'll actually do much with the noise under there, the devil system is borderline at brands and the limit is 105dB there :rolleyes:

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I've got the same problem with my one... I've put a 2.5 downpipe on there, and am making up my own 2.5 system to a supertrapp silencer, that way you can adjust the silencing to suit the track your at. I'm even making it easy to change over, to just bin the supertrapp and have a straight pipe if needed.

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Originally Posted by olidaviesuk

One last thing - was considering getting the car setup on a rolling road, as there isn't a large stretch of private road near me (other than brands), and haven't got a wideband.. I usually use track n' road in essex (the two Steve's), however, know they won't have the jets for the 5 in stock so was considering taking it up to bb, obviously people have 'differing' views on tuners, but are they competent to correctly set the fueling up etc..

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you'll have to do more than just change the jets to get the fuelling how you want it.... get your drill bits out for the enrichment circuit etc.
Look at buying one of the innovate motorsport wideband kits, well worth it, and quite cheap...

Steve & Steve @ Track n road :agree:

Just source some jets from Renault or K-tec, southern carbs & have a play yourself on the rollers... If you have a true grp A carb then i'm not sure what you'll gain really though as i've never played with one myself.

Take a soldering iron & micro drill-bits, and solder up the jets/re-drill them yourself accordingly.

Why not get an afr plot before you start worrying about ya carb needing work?

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Originally Posted by olidaviesuk

New poster! (less than 10 posts)

Yup is the standard devil side exit, main worry for me is noise testing, as cadwell and castle combe in paticular are really hot on it, and not exactly a lot of room to fit a silencer that'll actually do much with the noise under there, the devil system is borderline at brands and the limit is 105dB there :rolleyes:

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the K-Tec side exit it a good chunk quieter than your open pipe, with the standard turbo you should be fine on noise. If you need a bigger silencer you'll need to go rear exit.

New poster! (less than 10 posts)

Is more a case of getting DET in 4th on my recent test at brands :( fortunately it only fcuk'd the fire rings on the head gasket, so not the end of the world.. have a spare engine which I have already popped in the car, but not the point, so the plan is rebuild mark fish lump to better spec and run with the spare during testing...:sad2:

Am 99.9999999999999% sure that it's the ignition module not retarding under boost properly, however, not 110% sure its not the fueling without wideband or rolling road. Have another test at brands mid december, and can't stretch to a wideband in the meantime.. Just don't want to run the risk of f'ing another engine - and need to do the test to work out a starting point for tyre pressures and suspension settings for next year..

Bit of a catch 22' pain in the a'hole kind of situation.. as have already replaced the ignition module, and fuel pump with known good parts which leaves the FPR and carb jetting (have already rebuilt the carb) :crap:

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Originally Posted by Mart

Take a soldering iron & micro drill-bits, and solder up the jets/re-drill them yourself accordingly.

Why not get an afr plot before you start worrying about ya carb needing work?

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Originally Posted by olidaviesuk

New poster! (less than 10 posts)

Is more a case of getting DET in 4th on my recent test at brands :(

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that could be a fuel supply problem, and it may well not show up on a rolling road. In fact, if it's only showing in 4th I can guarantee that you won't see it on the rollers doing a normal pull. Hold it at 6K for 10+ seconds on the rollers (or for however long you're a full throttle on your longest straight).

if you suck on the tube going to the aei, does it hold a vacuum?