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PostPosted: Sun Apr 20, 2014 5:23 pm 
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Mike, for knock control why not look into using the SAAB APC system:
http://web.inter.nl.net/users/turbo-team-europe/apc.htm
It can be used as a stand alone electronic boost controller with knock feedback - could maybe work with your setup.

In your picture of the rear diff, is that black thing the UK market diff air scoop?

Car looks great :D


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PostPosted: Mon Apr 21, 2014 12:58 am 
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Thanks - I'll have a look through the link.

Yes the plastic bit is the air scoop. I think these are fitted to all non-JDM cars.

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PostPosted: Mon Apr 21, 2014 3:13 pm 
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It was interesting chatting to Wayne day before yesterday about mapping. He's not a great fan of putting in a lot of 'safety margin. As he said, over-rich mixtures and overly retarded ignition leads to the mixture still burning as the exhaust valve opens leading to overheating of manifold and turbo.
He was telling us about one of the manufacturers (can't remember which one, may be seat) producing an ECU setup that measures EGT and only adds extra fuel when required to keep temperatures down. Apparently some tuners have started using this ECU as a standalone in other cars.

My own thoughts are that it would be far better to have a good knock detection system and control strategy to keep ignition close to the edge without over-stepping the mark. The link G4 knock system would not be suitable for this in it's current level of development.

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PostPosted: Mon Apr 21, 2014 10:24 pm 
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At the risk of triggering an apoplectic fit from JP, water/methanol injection would be another option to reduce the risk of detonation.

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PostPosted: Tue Apr 22, 2014 11:01 am 
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On Cue....

I quite like the EGT / fuelling link by the ECU CDB mentions. I also like the Saab APC system. Both are really designed to counteract the effects of a dodgy batch of fuel IMHo and are not ideal for aftermarket tuners trying to push the engines above the safe boost limits - into "knock limited" territory - as a normal operating window.

Running the engine not overly rich or with retarded ign timing I also like (providing suitable safeguards are in place), I wonder if Seat or whoever it is has had to do it to safeguard a VNT turbo which are very prone to failure through high EGT?

Don...
If the WI system was fast enough to react to det and trigger the WI then it would be a sensible plan (presuming you have a decent knock detection strategy - here's the problem!) this along with an automatic reduction in boost. I fear that most WI systems are unlikely to be quick enough to react to save an engine. Running it full time slows the flame front speed similar to adding extra fuel all the time so I see little benefit.

Water & Methanol makes more sense than just water. It has its place at least, just not in my car!

In my head it makes more sense to not try and push through the pain barrier to a boost point above where the engine is happy operating, less exhaust back pressure (including turbo) higher flowing cams, more efficient intercooling, more efficient turbo setups will all help to increase the level of boost the engine can happily cope with as well as provide higher BHP in themselves. A better route to just turning up the boost :-)

Oh did anyone mention CR? Has anyone actually built a low CR 3s-gte? Did the loss of Squish effect turbulence remove the benefit of the lower CR WRT to where the engien becomes knock limited?

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PostPosted: Tue Apr 22, 2014 6:10 pm 
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I'm also a believer in gaining power by 'conventional tuning' rather than just turning the boost up, for two main reasons. The extra boost pressure requires more power to achieve which can only come from strangling the exhaust even further - leaving more hot, burnt mixture in the chamber reducing efficiency. Secondly, any ponies that come from boost aren't there when the driver first plants his foot to say he wants power. You need to wait for them to be born and then grow.

I was under the impression that the engine in completely standard form is 'knock limited' - i.e. it needs to run rich and a little retarded on boost. If the CR were dropped to a level where this were not needed then the bottom end response would be reduced - hence a compromise.

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PostPosted: Tue Apr 22, 2014 10:57 pm 
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Interesting discussion so here are my thoughts...

In my view EGT sensors are too slow acting to drive any kind of anti-knock measures like retarding timing or adding fuel or water injection

I don't see anything particularly wrong with running rich apart from the damage it does to your wallet. The 1980's F1 turbo engines employed this strategy during high boost qualy runs and you can see Rod Millens Toyota 503E race engine in his Pikes Peak Celica and Tacoma run rich. It's messy but it works! The only downside is the risk of bore wash. I understand the previous owner of my JDM ST205 lost an engine this way.

The normal 'kit' water injection strategy is pre-emptive triggering using boost pressure so its quite effective at combating the sudden rise in charge temperatures which are a consequence of higher compressor speeds. In practice this translates to the WI only activating during transient phases as you spool up the turbine during accelleration. Whether you'd describe this as 'full time' I'm not sure? Just to be clear I'm not planning on using WI as part of my standard strategy with my Track Toy unless I've grossly overestimated my intercooler capability :-) It should be more than capable of handling the ACT transients.

Don't Porsche use VNT turbo's? If the VNT units are prone to failure through hight EGT's I'd have thought the forums would be full of horror stories from the porker owners.

I'm not in favour of running road car engines close to det. The marginal increase in power may be worth it in a race car but pretty pointless in a road car where reliability is more important.

The current crop of turbo 1.6 litre World Touring Cars breathe through a 42mm intake restrictor and run 2.5bar absolute (1.5bar above ambient) at a 12.5:1 CR for 306bhp and 247lb-ft. This CR is not untypical of modern turbo engines and is a marked change from 1980's technology where CR's of around 7:1 were quite common in competition engines. This is probably due more to advances in materials science, cooling technology and most of all electronic control systems. Interestingly the Chevrolet Cruze TC1 touring car built by the highly successful RML team employs a Life ECU which is probably one of the most advanced ECU's available today having been developed originally by AER for their Le Mans 24 Hour LMP2 winning 2litre turbo engines.

As this is Mike's project thread I'd better just say that I agree with his approach of over-speccing his build and running the engine significantly below the power it would be ultimately capable of delivering :mrgreen:

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
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PostPosted: Wed Apr 23, 2014 11:37 am 
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Hi,

note, water injection is not able to effect the egt in a significant amount, the water is vaporized after the comprassion and not realy able to take more energy out of the burining chamber

but calculations with the right amount of water shows a effect like +10octan when running wi (pessimistic appraised)

greetz

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PostPosted: Wed Apr 23, 2014 10:45 pm 
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TrackToyFour wrote:
Interesting discussion so here are my thoughts...

In my view EGT sensors are too slow acting to drive any kind of anti-knock measures like retarding timing or adding fuel or water injection

I don't see anything particularly wrong with running rich apart from the damage it does to your wallet. The 1980's F1 turbo engines employed this strategy during high boost qualy runs and you can see Rod Millens Toyota 503E race engine in his Pikes Peak Celica and Tacoma run rich. It's messy but it works! The only downside is the risk of bore wash. I understand the previous owner of my JDM ST205 lost an engine this way.

The normal 'kit' water injection strategy is pre-emptive triggering using boost pressure so its quite effective at combating the sudden rise in charge temperatures which are a consequence of higher compressor speeds. In practice this translates to the WI only activating during transient phases as you spool up the turbine during accelleration. Whether you'd describe this as 'full time' I'm not sure? Just to be clear I'm not planning on using WI as part of my standard strategy with my Track Toy unless I've grossly overestimated my intercooler capability :-) It should be more than capable of handling the ACT transients.

Don't Porsche use VNT turbo's? If the VNT units are prone to failure through hight EGT's I'd have thought the forums would be full of horror stories from the porker owners.

I'm not in favour of running road car engines close to det. The marginal increase in power may be worth it in a race car but pretty pointless in a road car where reliability is more important.

The current crop of turbo 1.6 litre World Touring Cars breathe through a 42mm intake restrictor and run 2.5bar absolute (1.5bar above ambient) at a 12.5:1 CR for 306bhp and 247lb-ft. This CR is not untypical of modern turbo engines and is a marked change from 1980's technology where CR's of around 7:1 were quite common in competition engines. This is probably due more to advances in materials science, cooling technology and most of all electronic control systems. Interestingly the Chevrolet Cruze TC1 touring car built by the highly successful RML team employs a Life ECU which is probably one of the most advanced ECU's available today having been developed originally by AER for their Le Mans 24 Hour LMP2 winning 2litre turbo engines.

As this is Mike's project thread I'd better just say that I agree with his approach of over-speccing his build and running the engine significantly below the power it would be ultimately capable of delivering :mrgreen:


Wayne was talking in terms of using EGT to control enrichment - i.e. cooling.

I think the first line of defence against det. is to pull timing as that is pretty instant, however doing so will lead to higher EGT so it's maybe then worth triggering WI as a second line of defence and then putting the timing back once it's had time to reach the cylinders.

I would disagree with you about not being desirable to run a road car close to the edge. Any power gained from advancing the timing is an improvement if MPG as you're extracting more power from the same cylinderful of mixture. Extra power from running less fuel is a double bonus. This is one of the prime reasons modern cars get better MPG without sacrificing performance. In order to achieve this, however, it is vital that the monitoring and control systems are in place to ensure that it doesn't overstep the mark. IMO these aren't available with the G3 as it stands, in which case I would agree that a good safety margin should be left.

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PostPosted: Thu Apr 24, 2014 12:16 pm 
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Mindful of this is mikes project thread and as this seems to be a good technical discussion may I suggest we split the thread mods?

I don't know the right answer....
My concern is that flame front speed is highest (faster burn) at the peak power AFR ratio (circa 12.6:1), leaner or richer mixtures burn slower and hence adding more fuel and retarding the timing is likely to result in a higher probability of combustion in the turbo/exhaust. If you set the timing based on a 12.6:1 AFR then a *bleep* up in fuelling either way will add more safety against Det. The downside is that the leaner mix of 12.6:1 will burn hotter and therefore is more likely to det to start with and may require retarded timing to limit peak cylinder pressure and reduce the chance of det.

It seems WTCC use 102 RON fuel - a bit of a benefit but not as much as I expected for 12.5:1 CR and 1.5 bar of boost..... must mean the engine was designed for it in the first place and bore/stroke/rod ratio/exhaust back pressure/intercooling and cam overlap all optimised.

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PostPosted: Thu Apr 24, 2014 1:21 pm 
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Diceman wrote:
Mindful of this is mikes project thread and as this seems to be a good technical discussion may I suggest we split the thread mods?


Damn right! Gerroffff my land!

:D :D :lol:

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PostPosted: Tue Mar 24, 2015 8:21 pm 
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3 questions, which If I don't ask on here I will simply forget to ask you later
1) With the Dinitrol how many cans did the car require and is it available in black?
2) How has the under seal held up?
3) As regards the subframe bushes are they from gt4 racing EU?

Cheers

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PostPosted: Tue Mar 24, 2015 11:48 pm 
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Hi Peter,

I used 3 cans of the waxy hard drying dinitrol stuff and 2 cans of the stickier cavity protection. At last inspection it had held up very well.

Yes the subframe bushes are from gt4 racing - I highly recommend them. Happy to take you out in the car at some point when you are next available.

Cheers :)

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PostPosted: Wed Mar 25, 2015 11:51 am 
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Sounds good, wouldn't mind seeing what this fully forged malarkey is about, although I am yet to really test the potential of the standard output. As regards the Dinitrol, was it the memorably named 4941 500ml cans of the main waxy stuff. Found 3xcan pack on the 'Bay' for the £30, which is pretty reasonable.

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PostPosted: Wed Mar 25, 2015 1:22 pm 
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Hi Peter,

I can't remember the part numbers - here is a picture of what I used - the ML is the cavity wax and the Metallic the main stuff.

Image

A forged engine is a nice thing, but it isn't the easiest or cheapest thing to do properly. There are very few people out there who know how to do it right on the 3S-GTE so it can be a real challenge.

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