in 2 minds eaton or r1 jabbasport g ladder

[hayesey]

g60s aren't very strong chargers, they don't like being revved up really quickly and wont be anywhere near as reliable as a turbo.  expect to have to rebuild the charger on a regular basis and to have to replace it sometimes too.  Also the power delivery of the charger means it's highly likely you'll be eating gearboxes.

a 200bhp 1272cc turbo engine will be more reliable than a 200bhp 1272cc engine with a g60 on it.  and charger rebuilds arent cheap.  replacement chargers arent cheap either.

as for which is better, well it's a matter of opinion, you'll have to make your own mind up.

[Ä‘uro]

g60s aren't very strong chargers, they don't like being revved up really quickly and wont be anywhere near as reliable as a turbo.  expect to have to rebuild the charger on a regular basis and to have to replace it sometimes too.  Also the power delivery of the charger means it's highly likely you'll be eating gearboxes.

a 200bhp 1272cc turbo engine will be more reliable than a 200bhp 1272cc engine with a g60 on it.  and charger rebuilds arent cheap.  replacement chargers arent cheap either.

as for which is better, well it's a matter of opinion, you'll have to make your own mind up.

regarding price you are right...chargers are not cheap. but they will make more torque than turbo nd torque is thing what accelerate your car. so it means car with carger will be faster than car with turbo (same horse power)...

and what about K04? is this turbo to big for standard bottom or not ?

[djtez]

Yoof - i had no idea about the 12.5 / 12.7... wat the hell you doing to that polo LOL !
Did you feel that lifting the back end helped alot on the drag ?
I have a PPP subframe im guessing this helps traction and stability too..

I'd like to know more about your polo or this a wee secret project ?

[Yoof]

Terry- no secrets here http://www.polog40.co.uk/forum/index.php/topic,1160.0.html

[hayesey]

if you mean more torque lower down the rev range then all that does is cause more uncontrollable wheelspin, the slightly more progressive power delivery with the turbo makes for very slightly easier launches and corner exiting, not to mention making life a bit easier on the gearbox.  If you mean lower peak torque then i dont agree that you get that with a turbo.  k04 is  ok but turbos are very expensive, might as well use garrett turbos if you are going to that expense.

g60s aren't very strong chargers, they don't like being revved up really quickly and wont be anywhere near as reliable as a turbo.  expect to have to rebuild the charger on a regular basis and to have to replace it sometimes too.  Also the power delivery of the charger means it's highly likely you'll be eating gearboxes.

a 200bhp 1272cc turbo engine will be more reliable than a 200bhp 1272cc engine with a g60 on it.  and charger rebuilds arent cheap.  replacement chargers arent cheap either.

as for which is better, well it's a matter of opinion, you'll have to make your own mind up.

regarding price you are right...chargers are not cheap. but they will make more torque than turbo nd torque is thing what accelerate your car. so it means car with carger will be faster than car with turbo (same horse power)...

and what about K04? is this turbo to big for standard bottom or not ?

[Tommo]

K03 is good for 200bhp+ 

As you have proved, but I still maintain the belief that a K03 is being pushed to (or even beyond) the limit at this and is working at exteremly low efficiency, hence people having to use water injection and massive intercoolers to keep the inlet charge temps down, as well as (im assuming) retarding the ignition excessively.
   Surely anyone seeking 200bhp must use a larger turbo than a K03 in order to avoid spending rakes of money keeping the charge temps down, all for a setup with poor efficiency.

IMHO I dont think that any supercharger can compete with the turbo as far as performance is concerned, a supercharger carrys no real advandages in a front wheel drive car IMHO. The decision lies with personal preferance, some people are particularly fond of the superchargers characteristics, some like originality etc.

[Andy]

When testing running 23psi, scrapyard front mount, but no WI on a K03 and I've never seen above 50degC or so inlet temp - and that was with a 25degC ambient and 9.3:1CR. WI is mainly used either because the CR is too high for lots of boost (thanks to 9:1CR Accralite pistons - though off-boost driving is nice), or because the stock G40 pistons like to melt.

Spool-up on my K03 turbo'd car and Yoof's and Robin's (the only others I've driven) is so much quicker than the T25'd car I've also driven - which makes it much quicker in real terms, even though peak hp isn't that different.

Doing crude Corky Bell maths I figured that much more than 18psi on a K03 would be pushing things a bit far. Using various more in-depth turbo-sizing programmes we've got at work they suggested that 22psi and circa 210bhp might be possible before things got really silly - though my VE figures were probably a bit optimistic, even for a well modded 8v BV head.

The dynos suggest that running 21psi or so definitely gives you gains, though I don't think much beyond that on 1341cc with 9:1CR gets you anywhere. The inlet temps remain in a sensible ballpark, which just leaves the potential overspeeding issue. Given that the 20v boys push the same turbos much harder without issue, and that they're cheap as chips, why worry?

[Tommo]

Hmm, I trust what you say Andy, and it sounds like you have clearly researched the subject of using a K03 much more extensively than I have. I must admit that the foundations of my argument lie purely on looking at a K03 comressor wheel and thinking it looked like it just wouldnt flow enough air.

Assuming what you say is correct, how can it be explained that my car made such good figures on 18psi of boost, with no BV head (just an extra 60cc or so capacity) and through a carb with a 25mm venturi?

I could do with fitting a thermocouple to my inlet really to see what its running, im sure my car gets nowhere near 50 degrees though, after heavy loads I have measured both sides of my IC with an infra red thermometer and its usually around 30 C and 20 C respectively, if its high speeds on the motorway then the pipe to the carb is usually cold to the touch. Although this isnt on a hot summers day as you described.

As for the C.R, I have run my standard Spi engine at 1.2 bar and after around 5k miles of abuse there isnt a single det mark in a piston or the head. Althogh admittedly it runs excessively rich on boost and the timing has always been kept conservative.

How much ignition advance do you typically map into a high powered G40 turbo? I have a suspision that there is a lot of horsepower to be gained by obtaining the right balence of boost and ignition advance, and the more advance I can run, the less likely my exhaust valves are to drop, and the less boost I can run, (for the same power)

[djtez]

Terry- no secrets here http://www.polog40.co.uk/forum/index.php/topic,1160.0.html

that was a good read yoof.. Sorta makes me trust more in wat you say..
Glad us on clubg40 have such a talented person on here.

p.s Looking forward to my new charger

[Yoof]

Hmm, I trust what you say Andy, and it sounds like you have clearly researched the subject of using a K03 much more extensively than I have. I must admit that the foundations of my argument lie purely on looking at a K03 comressor wheel and thinking it looked like it just wouldnt flow enough air.

Assuming what you say is correct, how can it be explained that my car made such good figures on 18psi of boost, with no BV head (just an extra 60cc or so capacity) and through a carb with a 25mm venturi?

I could do with fitting a thermocouple to my inlet really to see what its running, im sure my car gets nowhere near 50 degrees though, after heavy loads I have measured both sides of my IC with an infra red thermometer and its usually around 30 C and 20 C respectively, if its high speeds on the motorway then the pipe to the carb is usually cold to the touch. Although this isnt on a hot summers day as you described.

As for the C.R, I have run my standard Spi engine at 1.2 bar and after around 5k miles of abuse there isnt a single det mark in a piston or the head. Althogh admittedly it runs excessively rich on boost and the timing has always been kept conservative.

How much ignition advance do you typically map into a high powered G40 turbo? I have a suspision that there is a lot of horsepower to be gained by obtaining the right balence of boost and ignition advance, and the more advance I can run, the less likely my exhaust valves are to drop, and the less boost I can run, (for the same power)

Tom- only accurate way is a thermocouple, skin temps of pipes are irrelevant. For example I know the skin temp of our V8 cats is 650'C, the EGT is in closed loop control at this point at 950'C.

I'd have thought, that a properly mapped G40 with 9:1 CR would exceed your 1.4 bhp if fitted with a similar turbo set-up, partly due to the finer control over ignition and fuel, but also the larger TB. The Renault 5 boys make do with tiny carbs and alot of boost though, and that's a proven combination- annoyingly quick too!

Good to see someone innovating rather than imitating for once, a refreshing change- hats off to you.

I'm currently modelling a G40 engine in Wave, once I've finished it if you give me some ABD figures I could make some interesting theoretical comparisons- beats buying 5 camshafts 

[Tommo]

Tom- only accurate way is a thermocouple, skin temps of pipes are irrelevant. For example I know the skin temp of our V8 cats is 650'C, the EGT is in closed loop control at this point at 950'C.

I'd have thought, that a properly mapped G40 with 9:1 CR would exceed your 1.4 bhp if fitted with a similar turbo set-up, partly due to the finer control over ignition and fuel, but also the larger TB. The Renault 5 boys make do with tiny carbs and alot of boost though, and that's a proven combination- annoyingly quick too!

Good to see someone innovating rather than imitating for once, a refreshing change- hats off to you.

I'm currently modelling a G40 engine in Wave, once I've finished it if you give me some ABD figures I could make some interesting theoretical comparisons- beats buying 5 camshafts 

Yeah I know that wall temps are a poor indicator, but with around ambient temps the difference will be relatively low, I will get around to thermocoupling it eventually.

Im absolutely posotive that it would make more power on a car with EFI and the larger TB as you say, the setup I have is about as crude as it gets. Im also confident that with an hours dyno time my car would make a significant amount more, but I just cant be arsed fiddling around with jets to get the carb to fuel correctly, thus is the advantage of mappable EFI.

I have no idea what WAVE is, im guessing its a physics modelling software for engines/pumps? It sounds like a much cheaper way to tune an engine thats for sure! Although as we say at work when somthing fails "well it worked on ProE!"



Your car should be spectacular when you get it going with the new turbo, your compressor wheel is ever so slightly larger than mine, and your turbine wheel is the same. Pretty much the same turbo just with ball bearings. Are you sticking for the .64 turbine housing? If you do I would be interested to see what its like for lag etc, mine has a .49 housing but im not sure if this will begin to choke up at much over 230bhp. Keep an eye out for compressor surge, as im guessing you wont really be on the map till your making around 150bhp +.

[giorgio]

I'm currently modelling a G40 engine in Wave

Have modeled the turbo to go with? I have tried a few times to model a sucky/blowy machine but can never get the model to work. I have copy of an old CBR600 turbo engine from Formula Stupid but I am running 8 and the model is in 7 so they are not compatible.

You a fan of 4Stroke Head? Keep getting told that its better for development than WAVE but I find it impossibly hard to self-teach it.

[Andy]

Tommo - Ricardo WAVE info is here:
http://www.ricardo.com/en-gb/Software/Products/WAVE/

WAVE RT is supposed to be the tits for development given its real-time calc capability - certainly looked pretty good when they were writing it, but never played with it directly myself.

Your car clearly made good power thanks to the better flowing turbo - at around 200bhp on a 1.3 8v Polo engine the K03 seems to be at its limit. We tried Robin's at 23psi, but after taking out enough timing to stop it detting it felt slower than on 21psi - and it definitely seemed to be a decent sweet spot on the dyno.

Still need to take a timing light to a Digifant car to work out the conversion factor between the hex in the map and actual degrees of advance. My own car's not on Digifant, so can't check on that - though at 6k on full-boost my Emerald reckons on giving me 12deg of advance. Base timing is set at 66deg BTDC.

[hayesey]

ooh there's a linux version, would I be right in guessing that it's mind-numbingly expensive?

[giorgio]

if your referring to me/4 stroke head then I know a man who knows a dog about a copy etc