New Member

[Flarty]

Tidied up the wires above the turbo this afternoon and ordered some new boost hoses, I also found the swirl pot with pipe work still attached in a box of spares that came with the car so not sure why this has been removed. Will try and get my head around the diagram tomorrow and see what's what.

Based on the previous comments i think a T2/T25 hybrid is the way to go for now, if at some point in the future want more then we can look at other options but i assume a T2/T25 hybrid running 18-20psi should be a nice increase in power from the stock T2 at 14psi?

What type of car's will a GT Turbo running above be able to see off?

I have spare carb sitting here that i got to re-jet for a bigger turbo but i'm in two minds weather or not to buy service kit and service my current known working carb or use the spare? what do you think?

[phase i 16 v turbo]

Hello and welcome, nice to see another black one

[Ian S]

If you haven't seen this, there might be some useful information in there; note the tuning guide at the bottom of the page

https://www.rtoc.org/boards/showthread.php?t=22002

To get torque and power, you need to get the engine to 'breath', ie, flow gas. You can pump as hard as you can with the compressor, but it'll do you less and less good if the gas isn't flowing, including out of the exhaust. As the back pressure rises from the exhaust, and from the small turbine, the engine becomes less and less efficient, and even with high boost, the power isn't commensurate compared to a well flowing configuration.

[Flarty]

What size is the stock exhaust system? I'm not sure what exhaust is currently on the car, the down pipe is clearly standard and the back box is clearly aftermarket but i am not sure on the rest of the system.

here's a picture does this look stock? Ill measure the bore size when i get a chance.

[Trevhib]

You could take up the offer being made at the end of this thread and have something awesome from front to back for £200:

https://www.rtoc.org/boards/showthread.php?t=39679

[Flarty]

You could take up the offer being made at the end of this thread and have something awesome from front to back for £200:

https://www.rtoc.org/boards/showthread.php?t=39679

That looks like a great offer but If i change the exhaust it will be going to a garage who have a ramp, Id rather not risk trial fitting something that potentially might not fit especially when I'm paying somebody else to do it but thanks for the heads up.

I'd like to find out if my current exhaust is actually stock or not first if anybody can tell from the picture or can tell me the standard exhausts bore size? Just how restrictive is the stock exhaust? I might just go ahead and see how she goes on the T2/T25 first, i think it might be enough for me and i can look at changing the exhaust at a later date, seems a bit of a shame to change it if its not necessary as the current one doesn't look like its been on the car very long at all.

[francob80]

Hard to tell from that picture, the back box doesn't look standard. I think standard bore is 2".

[Flarty]

Ill see if i can measure the current one, There's a 2.5" one local to me on ebay too ill keep an eye on.

On another note I've just been told i will need det can's running anything over 16psi, Ive no experience with det can's, so would appreciate any advice on here, i assume i need some that extend into the cabin to listen while on boost, what type of det can's do i need and how do i know what to listen for?

EDIT, found some examples of what to listen for on youtube, Any recommendations for easy to set up and route into the car det can's?

[francob80]

Not sure about det cans at 16psi but if you are that way inclined you can buy a mechanical steth with some 6mm nylon tubing and attach to head. Then run through to the cabin.

[Flarty]

Not sure about det cans at 16psi but if you are that way inclined you can buy a mechanical steth with some 6mm nylon tubing and attach to head. Then run through to the cabin.

This is what I've been told is the safe limit before they are needed, by a member of another GT Turbo forum.

The plan is a T2/T25 hybrid set-up to 18-20psi.

[francob80]

This is what I've been told is the safe limit before they are needed, by a member of another GT Turbo forum.

The plan is a T2/T25 hybrid set-up to 18-20psi.

That's cool, to err on the side of auction it might be sensible however I bet a large percentage of people tuning 5's don't bother but you can have good AFR's and still get detonation.

A mechanical steth will do the trick.

[Flarty]

Have you come across many people experiencing det at 18-20 psi? Is this something that can be checked on a rolling road rather than buying det can's? I am a little concerned now having been told this.

[francob80]

Have you come across many people experiencing det at 18-20 psi? Is this something that can be checked on a rolling road rather than buying det can's? I am a little concerned now having been told this.

I'm sure there have been numerous people who have had their 5's detonating like mad at that sort of boost but mainly due to piss poor fuelling and very high charge temps.

Remember the standard intercooler is ****, even an alloy one in the same place as standard is in a poor position. Ideally you want to look at fitting a front mount cooler. There are other options like charge cooler or even water injection.

[R5MJH]

you dont need det cans for upto 20psi above maybe, loads run 20psi no probs as long as afrs are correct of course

[francob80]

By the way, you and I are chatting on two separate forums. haha !

[Flarty]

you dont need det cans for upto 20psi above maybe, loads run 20psi no probs as long as afrs are correct of course

Thanks i appreciate the response, I have been reading countless old threads on these forums and other forums for information on what spec's people have run etc and this is the first time i heard about det can's for anything over 16psi, I don't think i came across a single thread where they were even suggested on anything below 20psi That said i don't want to just ignorantly dismiss somebody else's opinion especially when they imply i might grenade my engine and have more experience than my self with these car's that would be very silly.

I am fully aware that increasing the boost on any engine in any car over standard comes with potential risks but from what i have gathered from numerous threads on this forum a T2/T25 with a correctly set up carb good afr's and uprated intercooler if the engine and all its ancillaries are already in good overall health then this was considered a relatively safe and reliable spec to run on an otherwise standard engine, to then hear i need det can's just as i was looking for the best place to order the turbo obviously set alarm bells ringing and made me re consider if i really want to pour money into modifications that are going to push then engine well beyond its ability's to remain reliable.

By the way, you and I are chatting on two separate forums. haha !

i've just realized who you are

[Ian S]

It's not that simple.

Ideally you need mappable ignition timing. And better control over the fuel would be good.

What we do / did with the standard 5GTT is a bit of a fudge.

If you're exhaust is quiet, you tappets are quiet, you are sufficiently perceptive, you can hear / sense / feel detonation. It doesn't even need to make the 'crack'ing sound, the knock is easily sensed by me anyway.

I designed and made my own electronic det detector / headphones. But I could sense it just the same without them. But not everyone could / can.

In my cars last configuration, I needed to not plant the loud pedal until the 'charge' air temperature was below about 40°C, or it would start det'ing before the overtake was done.

I also made and sold suitable high speed charge temp gauges.

The air temp exiting the turbo can be around 250°C. The OE intercooler drops that to about 89°C. The Pace charge cooler drops it to about 94°C. It was found the Forge universal front mount dropped it to about 40°C if lapping a track, but obviously as slower speed there is less cooling.

You are balancing off a few thing against each other; boost, air temp, ignition timing, fuelling. Also head temperature might factor in. And combustion chamber shape, I had mine altered a bit, and the liners bored a bit. Possibly more gas flow though the engine might cool it and allow more boost / cylinder pressure before det'ing, so a lower back pressure from a larger turbine (and better manifold) and free'er exhaust might make more power from the same boost.

To reduce the det and maybe run a few PSI more boost, you can back off the timing by about 4° by moving the TDC sensor one of the two direction. The other increases it about 4°.

My engine dett'ed quite a bit over the years but sustained no damage. When I took it apart after years of that, it was fine. The people who blast holes in their pistons, heads and gaskets must be very badly lacking perception and a feel for what they're doing and det'ing it very badly either for far to long, or under way extreme overboost / underfuel.

You'll have to estimate which type of driver you are. If you can't easily sense the changes, then your best not taking any risks.

My two engines failed due to valves dropping into the chamber, either collets coming off at over 7000rpm or valve top shearing off, or something. Not due to high boost. After that I didn't again want to spend money on that type of engine with push rods and rockers and felt a direct cam on valve design would be better. And a bigger chamber size and less boost.

[francob80]

Like ^^

[francob80]

I also made and sold suitable high speed charge temp gauges.

Any chance of making some more of these gauges ?

[Flarty]

Great post Ian, very informative.

I believe i am somebody who is very perceptive, i would go as far to say that is actually my strongest attribute, I have the ability to sense the smallest of changes in all things and ironically without getting into specifics this is how i make my living .

My only experience with knocking was some years ago with a mk1 fiesta which sounded like 20 miniature skeletons having a fight in a metal dust bin with tiny hammers, Similar to the crackling sound some car's make when you turn them off as they cool down. I also noticed the reduction in power, it felt like you were constantly driving up a hill like the engine was fighting its self.

I am not just thinking i'm going to whack on a big ass turbo and wind the boost controller all the way out to its last thread like its 1995 and some geezer in a rs turbos just pulled up next to me at the lights wanting it and then go rag the car all over the place. I am just trying to establish some sort of level of tune that is agreed upon from other peoples years of experience as being a relatively reliable safe state of tune. or do i really need, mapable ignition, control over fueling, charge temp monitoring, det cans and retarded ignition on a T2/T25 Upgrade? If that is the case then like your self i'm not sure im willing to pour money into a car that needs to be monitored likes its on a life support machine , I want a car that i can use and be driven properly without constantly worrying about it going boom, Id rather start with something either quicker or can handle more power without problems.

I love this little car, its great fun and has lots of character, its just not quick enough for me. as a youngster the 5 GTT was a car i looked at in awe, I remember some older guy's i knew talking about this turbo car that pinned you back in the seat and made pshhh sounds i was maybe 9 or 10, id never seen one or had any clue what they were taking about but they made it sound like stuff of legend. To bring the car up to the level of expectations i had imagine as a youngster it certainly needs more power.

I'm not sure what to do at the moment, This GTT was an itch i needed to scratch and i've enjoyed my short time with it, its a cracking car and i imagine back in its day it would have been awesome to own one but as i say its just not quick enough for me. Don't get me wrong at 14 psi its certainly not slow and still quick by many peoples standards but its not the big grin on your face mental i had conjured in my imagination as a youngster.

She is a beauty though.

[JRP]

I sense your all jedi's

[Flarty]

I sense your all jedi's

I sense you're in the know, based on your ability to sense this truth.

[JRP]

I sense you're in the know, based on your ability to sense this truth.

[Trevhib]

The standard exhaust is 2" and has a middle silencer (which yours doesn't). Your exhaust looks like a 2" after-market stainless item and wont be a great deal better than OE.

Also, it will be very cost inefficient getting a 2.5" exhaust system if the turbo elbow and crossover pipe remain standard. If you do the former, do it with the intention of upgrading the latter. It will make a big difference. Hence taking a punt on Matty's new system, even if it doesn't fit quite straight the first time.

I don't believe you need det cans below 20psi either. I'd say you need someone experienced to set the boost level and fuelling up for you according to the existing turbo and intercooler's capabilities.

[Flarty]

The prototype exhaust offered on here needs somebody to be able to test in within the next 2 week's which i am not able to do otherwise i would be very interesteed as it looks very well made indeed. What off the shelf exhaust systems are available that are not too loud? The current exhaust is not overly loud and doesn't drone on the motorway etc.

As for setting up carb fueling from what i understand this is just a case of playing with the jet's, Starting with enlarging the 2nd stage checking AFR's then if needed reducing the air corrector as the initial first two stages many people have reported running 20psi without needing to change any other jet's i would be looking to run 18psi and see how i found the performance. My current AFR's are high 11's at WOT which i'm told is fine?

[Ian S]

Any chance of making some more of these gauges ?

I'd like to but I'm not sure I can do it;
some of the parts I used have gone out of production,
last time I made 15 at once to make it economically viable for both myself and customers,
doing one or two would take maybe 10 to 15 man hours each where I got it down to 7 or so,
I was buying parts from about seven suppliers, meeting their minimum order quantities and price breaks.

I guess parts would come to £100 or so each and I wouldn't want to buy a reel of PTFE tube just for few centimeters, etc.

SPA were making a thermocouple based gauge but their price was high.

[Ian S]

14 psi

Is that at the manifold or before the throttle?

Power

What are you comparing it with? Power to weight was it's advantage. And too much of through the front wheel drive made it a bit barking mad! But the novelty did wear off of doing an overtake at 30mph with the wheels spinning from start to finish and turned to one or other side about 1/4 turn.

But one does feel connected to the driving experience, which a lot of cars (intentionally?) don't give.

I think how ever much power and overtaking performance one has, it soon seems not enough. I fancied Ken Blocks 700BHP fiesta (from his gymkhana video) to drive on the lanes over to my relatives. No traffic in the way then! But his tyres only last 5 minutes! How fast can one afford to go?

[Flarty]

Is that at the manifold or before the throttle?

What are you comparing it with? Power to weight was it's advantage. And too much of through the front wheel drive made it a bit barking mad! But the novelty did wear off of doing an overtake at 30mph with the wheels spinning from start to finish and turned to one or other side about 1/4 turn.

But one does feel connected to the driving experience, which a lot of cars (intentionally?) don't give.

I think how ever much power and overtaking performance one has, it soon seems not enough. I fancied Ken Blocks 700BHP fiesta (from his gymkhana video) to drive on the lanes over to my relatives. No traffic in the way then! But his tyres only last 5 minutes! How fast can one afford to go?

My boost gauge is tapped into the vacuum line running to the AEI unit.

The car is technically already quick enough i'm not after more speed, its the novelty of being pinned back into your seat 2nd and 3rd gear for example, I had a saab 9-5 aero early 230bhp model which felt around as quick as the GTT currently feels, already quite quick but i wasn't satisfied . I tuned that in various stages and was finally very happy when abbot racing tuned it to a claimed approximate 300hp, I kept it for around 15 months and did 25k miles and the novelty of 2nd and 3rd gear pulls never wore off.

[francob80]

I love this little car, its great fun and has lots of character, its just not quick enough for me. as a youngster the 5 GTT was a car i looked at in awe, I remember some older guy's i knew talking about this turbo car that pinned you back in the seat and made pshhh sounds i was maybe 9 or 10, id never seen one or had any clue what they were taking about but they made it sound like stuff of legend. To bring the car up to the level of expectations i had imagine as a youngster it certainly needs more power.

I'm not sure what to do at the moment, This GTT was an itch i needed to scratch and i've enjoyed my short time with it, its a cracking car and i imagine back in its day it would have been awesome to own one but as i say its just not quick enough for me. Don't get me wrong at 14 psi its certainly not slow and still quick by many peoples standards but its not the big grin on your face mental i had conjured in my imagination as a youngster.

If you want mental and big grin you are going to have to put much more power into it than just a turbo and a bit more boost.

Mine weighs around 800kg with approximately 220/230hp and that more than does the job. Pointless in the wet but in the dry with R888s it grips well with next to zero wheel spin. The problem is if you aren't willing to put some money into it you won't get to this stage, it has cost be a fair amount to get there.

[francob80]

I'd like to but I'm not sure I can do it;
some of the parts I used have gone out of production,
last time I made 15 at once to make it economically viable for both myself and customers,
doing one or two would take maybe 10 to 15 man hours each where I got it down to 7 or so,
I was buying parts from about seven suppliers, meeting their minimum order quantities and price breaks.

I guess parts would come to £100 or so each and I wouldn't want to buy a reel of PTFE tube just for few centimeters, etc.

SPA were making a thermocouple based gauge but their price was high.

What about if we could get 10 people interested and willing to put down a deposit to help get you started ? Would that help ?

[Ian S]

If you want mental and big grin you are going to have to put much more power into it than just a turbo and a bit more boost.

Mine weighs around 800kg with approximately 220/230hp and that more than does the job. Pointless in the wet but in the dry with R888s it grips well with next to zero wheel spin. The problem is if you aren't willing to put some money into it you won't get to this stage, it has cost be a fair amount to get there.

Me too.

Once I had the T28 fitted it was laggy but there was no going back from that, it's open road performance was

Around town though, and back doubles, rather hard work and a bit annoying. Hence I wanted to next fit a lower boost 2 litre. A pals one on 6psi was making 250bph and 230ft lbs. He said most of the time he barely needed the boost. I was planning to use a Megane engine based on the 1.7, apparently the same size block as the 5, rather than the larger quite a bit heavier Clio 172, etc. Ran out of spare money.

Whether a boosted 1.4 5GTT would match the fun of a 300bhp Saab, hard to tell, but my 5 out dragged pretty much everything. I didn't have R888 but did briefly run some Yoko A032 which also cured the wheel spin. I fitted 15's so sold them.

[Flarty]

If you want mental and big grin you are going to have to put much more power into it than just a turbo and a bit more boost.

Mine weighs around 800kg with approximately 220/230hp and that more than does the job. Pointless in the wet but in the dry with R888s it grips well with next to zero wheel spin. The problem is if you aren't willing to put some money into it you won't get to this stage, it has cost be a fair amount to get there.

Right F it if im going to do it lets get this done done properly

Out of interest what is your full spec mate most of it is in your profile anything missing from that exhaust? interested to see what front mount inter cooler you are running.

Is there any front mounts that don't require hacking the front bumper?

[francob80]

Spec is C1J engine with piper 285 cam, vernier pulley, piper springs, completely standard bottom end. Helix paddle clutch and TTV flywheel about to be fitted. (Current clutch just slips on boost)

Rejetted carb
Malpassi adjustable fuel pressure reg
2.5 side exit
2.5 custom down pipe
GT2560r turbo
forge actuator with 20 psi Spring
Tubular manifold (wouldn't bother with this, plan is to put the standard cast one back on)
Large front mount cooler. (In my case I removed front cross member to fit)
Cossie style K&N air filter
Stripped out - 6 point safety devices cage
Corbeau buckets

I think that's pretty much it, the final piece for me is a decent set of coil overs.

Also yea there are coolers that you don't need to hack bumper etc. I think there's a thread on here somewhere, perhaps in the tuning article section.

[francob80]

Right F it if im going to do it lets get this done done properly

Out of interest what is your full spec mate most of it is in your profile anything missing from that exhaust? interested to see what front mount inter cooler you are running.

Is there any front mounts that don't require hacking the front bumper?

Here's the intercooler.

[IMG][/IMG]

[Flarty]

That inter cooler looks huge lol What's my best option without having to chop away at anything? I wasn't to keep the body as original as possible. Ive seen a couple of people with a rad/inter cooler in one unit. but can't find any like this for sale.

[francob80]

That inter cooler looks huge lol What's my best option without having to chop away at anything? I wasn't to keep the body as original as possible. Ive seen a couple of people with a rad/inter cooler in one unit. but can't find any like this for sale.

This thread tells you about coolers - https://www.rtoc.org/boards/showthread.php?t=4755

[francob80]

That inter cooler looks huge lol What's my best option without having to chop away at anything? I wasn't to keep the body as original as possible. Ive seen a couple of people with a rad/inter cooler in one unit. but can't find any like this for sale.

With bumper fitted - Ignore the big hole, its a work in progress and will probably be swapped with new/different bumper. But you can see cooler is nice and hidden.

[IMG][/IMG]

[Flarty]

That looks good actually, i thought the front of the bumper was cut, Does cutting the cross member not effect the structural integrity tho?

[francob80]

That looks good actually, i thought the front of the bumper was cut, Does cutting the cross member not effect the structural integrity tho?

Hmm well quite possibly, I guess you could argue removing the cross member loses some structural integrity but by adding the cage and strut brace I guess I'm putting some of that back into the car. Many people have removed the cross member to add similar size cooler before so I decided to bite the bullet myself. 5's aren't exactly at the top of the tree when it comes to strength lol, as you know they are made out of tin foil.

The down sides with this particular cooler is you do have to chop a bit of the bumper mainly around the fog light section which means you can't really refit the fogs (maybe be able to find a fix for this, just haven't tried yet) as the inlet/outlet hoses get in the way, as it's mainly going to be a track/weekend toy this didn't bother me. Your's however looks much cleaner than mine so you may want to keep all of that intact. Maybe a smaller cooler will work allowing you to keep cross member and fogs.

[Flarty]

Found a few old threads on here from people running universal front mount's without cutting anything, Will pop the bumper off and have a good measure up and see what will fit.

BTW What are your AFR's like at 20psi?,

[francob80]

Found a few old threads on here from people running universal front mount's without cutting anything, Will pop the bumper off and have a good measure up and see what will fit.

BTW What are your AFR's like at 20psi?,

mid 11s currently at 7k in 4th, still more power past 7k on mine but I need to increase rev limiter slightly. Also until new clutch is fitted it just slips so can't properly set it up.

[turbo ted]

That looks good actually, i thought the front of the bumper was cut, Does cutting the cross member not effect the structural integrity tho?

Cutting cross member does not effect the structer as all stress goes through the subframe my cross member gone along time now and I'm putting 611hp through it

[francob80]

Haha there you got Flarty, if it's good for 600hp it's good enough for our measley attempts.

[Flarty]

Cutting cross member does not effect the structer as all stress goes through the subframe my cross member gone along time now and I'm putting 611hp through it

Well i guess that clears that up lol.

[Flarty]

And so it begins.......no going back now, i guess you only live once

[James5]

And so it begins.......no going back now, i guess you only live once

T25 what size is the rear housing?

[Flarty]

.49,i think .47 is preferd on the t25 so may be a bit more laggy than id like but was a very good price and is coming from a reputable person who runs a renault 5 race car.

[James5]

.49,i think .47 is preferd on the t25 so may be a bit more laggy than id like but was a very good price and is coming from a reputable person who runs a renault 5 race car.

.49 will be fine full boost around 3300-3500rpm's, I ran a T28 with .49 rear I actually liked the way it drove I even managed a good 1/4 time on it @18psi when you look at others around my time on the leaderboard and the spec of my setup was much lower than other's

[Flarty]

.49 will be fine full boost around 3300-3500rpm's, I ran a T28 with .49 rear I actually liked the way it drove I even managed a good 1/4 time on it @18psi when you look at others around my time on the leaderboard and the spec of my setup was much lower than other's

That's good to hear a little lag might be beneficial in some scenarios as i find the little t2 wants to boost all the time when just pottering around, and on the motorway you can't really cruise at 70 in 5th without it wanting to boost either. I am not sure why anybody complained about turbo lag on these cars back in the day.

[Ian S]

Without that small augmenting boost, all you have is a low compression 1.4 litre. It's surprising slow.