Club G40 Forum
Technical => Turbochargers => Topic started by: gavin.starr on March 29, 2011, 04:16:12 pm
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Just a quick question to see what a good set up would cost to turbo the g40 engine, I looked into doing a single turbo conversion on my supra but when I realised it was going to cost me more than what I paid for the car in parts I thought sod it (£8500).
So for a descent set up what are the costs likely to be on the G. Im just curious as i may go down this route later on through the build in a year or so.
Gav
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if you buy used parts from ebay or private sellers and build by yourself you can get the job done for about 500£.
search for saab turbos on ebay in case that you want a garrett or for vw 20v turbo or 1.8t in case you want to go for kkk03.
you can get a turbo in good shape for about 150£
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Depends on how far you go with it but basic hardware can be bought for the same sort of price you would get for a r1 charger and toothies set if you have a 4 branch aswell to flog your pretty much on track for getting straight swap rough costs
turbo £80
manifold £200
downpipe £150
boost (silicone),pipework £100
intercooler £50
turbo water and oil lines and fittings £100
that's most of what you'd need asa minimum but as I said depends on how far you go, as it can snowball easily, like oh I'll just rebuild this and oh mayaswell do that before you know it the engines out so on and so on. But it can be done pretty cheaply and effectivley on a small budget if your the sort of person that can stick to one !
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I cant do things by halves so it would prob's cost me a small fortune.
I have already set aside a fair wedge for doing my Bready conversion, so to turbo it doesn't sound to bad to me, so I can see me doing it sooner than later. I cant see me keeping my Supra much longer as its doing my tits in. I have just replaced all the rear suspension arms at a cost of £1500, and the bloody thing still doesn't drive the way I want it to.
Thats why I love to polo because things are so cheap for them.
Gav
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parts can be cheap(ish) if you can find them second hand (like i did ;) ) otherwise its on the phone to Rothe in germany to order one of their kits!
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Unexpected things like oil coolers, gauges etc. can bite you in the ass. You'll need a map too @~£80 for an 'off the shelf'.
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or £40 as ive got one for sale ;D
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What are these engine like for reliability once they are turbo'd I presume they don't need to be serviced as often as the charger does.
I would probably start from the ground up and give the engine a load of new parts first before I start putting more power to it.
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The turbo would need servicing once in a while but not as often as a G-lader.
I'm sure Hayesey, Yoof or Robin will appear and let you know about reliability but tuned right, should give you problem free motoring.
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Depends on how far you go with it but basic hardware can be bought for the same sort of price you would get for a r1 charger and toothies set if you have a 4 branch aswell to flog your pretty much on track for getting straight swap rough costs
turbo £80
manifold £200
downpipe £150
boost (silicone),pipework £100
intercooler £50
turbo water and oil lines and fittings £100
that's most of what you'd need asa minimum but as I said depends on how far you go, as it can snowball easily, like oh I'll just rebuild this and oh mayaswell do that before you know it the engines out so on and so on. But it can be done pretty cheaply and effectivley on a small budget if your the sort of person that can stick to one !
I think you forgot cam for turbo - app 120£ ;)
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I wouldn't say a turbo conversion will be more reliable than an original g40 at all really. The reliability will be down to how well the conversion is done, how well it's remapped, how many parts you replace and perhaps most importantly, how much boost you decide to run. You just can't slap a turbo on, set boost to 21psi and expect the car to be as reliable as a standard g40 running about 7 psi.
However, the turbo is more progressive than the supercharger in the way is delivers boost so this is a bit more forgiving than running equivalent power with a supercharger on the drivetrain components.
I would also factor in £500+ for a proper custom remap.
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Best advice I think is as hayesey says, all depends how well the conversion is done, which will of course alter the cost.
Out of curiosity, is anyone running a ~150bhp turbo G40, instead of the full fat ~200bhp ones.
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Not sure, that's half the problem, once you go turbo it's far too easy to turn the boost up! :D
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I might even buy another polo to start getting on with, I love the idea of having a turbo'd one ;D
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A few other 'hidden' costs to consider:
Injectors (250cc or 310cc dependant on power)
Fuel Pumps (replace/ uprate dependant on power)
Rad fan- stock item isn't really up to the job with the extra heat from the turbo into the
cooling circuit.
Forge Actuator (K03)- Adjustable boost levels
Camshaft- Newman/Schrick etc to suit capacity and turbo
Oil drain fittings
Silicone hose (don't underestimate the cost of doing this properly!)
Dump valve
Map to suit (or custom remap)
Clutch
Chassis/brake mods to cope with power!
It all depends how far you want to take things, for a good budget 170bhp that's reliable I'd run the following spec:
250cc injectors, stock map sensor, K03 with either forge actuator and 15psi spring, or stock with bleed valve (not ideal), large front mount intercooler, and a 63mm downpipe to a 2.5" system, rothe cast manifold (flow 220bhp+ and won't crack!) and an organic clutch.
That's a turbo setup, that with an injector/map and boost increase will make 190bhp+
I.e spend money early and make it 170bhp, get used to it, then upgrade for a few hundred to 190bhp+ ;D
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Sorry to meander off topic but is the K03 still best for under 200bhp given that the manifolds and downpipes are relatively easy to get hold of?
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Rad fan- stock item isn't really up to the job with the extra heat from the turbo into the
cooling circuit.
is this the case i thought that the stock fan and cowling was pretty good as the clowing helps guide the air around it i wen out of my way to refit the stock on in a new position when i did mine is a slimline aftermarket one realy much better then ??
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Be interested to know this
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Sorry to meander off topic but is the K03 still best for under 200bhp given that the manifolds and downpipes are relatively easy to get hold of?
pretty much, unless your good at fabricating own a scrap yard or have acess to equipment parts that may make other options cheaper but even still you'd be hard pushed to get a setup as cheap as you can now do k03 for especialy with the large amount of knowledge avalible for this setup now.
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Rad fan- stock item isn't really up to the job with the extra heat from the turbo into the cooling circuit.
is this the case i thought that the stock fan and cowling was pretty good as the clowing helps guide the air around it i wen out of my way to refit the stock on in a new position when i did mine is a slimline aftermarket one realy much better then ??
The plastic cowling in front of the radiator is always beneficial, as it ducts moving air onto the cooling pack when the vehicle's moving - but it's difficult to retain the stock plastic cowling once you've whacked a front-mount on there.
The stock fan and metal rear cowling are effective at keeping the car cool in stationary traffic and that's the point of them.
However, once on the move the effect of the radiator fan is much less significant than the natural ram air effect. It's at this point that the stock fan and metal cowling start hampering cooling. The metal cowling covers a large portion of the radiator, but presents quite a bluff surface to oncoming air which slows the air speed down massively. Remove the fan and the metal cowling, and your cooling at 50mph is significantly improved.
When you're stationary in traffic, your boosted Polo engine is pretty much no different to a 55bhp AAV in terms of heat rejection, and in UK ambient temperatures overheating in traffic is just not an issue. So go for a slimline fan (more effective/efficient than a stock one) to deal with stationary traffic situations, and remove the metal cowling to get optimal cooling on the move (i.e. when you're ragging it and the engine's producing lots of waste heat).
Mine, Robin's, Hayesey's and Yoof's turbo'd G40s are all fine in traffic. But mine gets very hot when ragging - and I'm the only one with a stock fan and metal cowling, the others have slimline fans and no cowling.
An old trick was to cut holes in the metal cowling and rivet flaps of stiff rubber over the holes. That way at stationary/low speeds the flaps are closed and the rad fan can draw air through the cowling effectively cooling the whole radiator, but at higher speeds the flaps are forced open and you benefit from the forced air cooling without the restriction of the fan/cowling.
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Mine still has the standard fan and cowling too andy. But I do want to get rid of it for a slim line one for the reasons you say there. Just gives a bit more under bonnet space too
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Intresting never even thought of the metal cowling hampering flow at higher speeds just always thought about it in traffic realy. Makes good sense though, does your andy and hayesey golet warmer than usual when on the move then ?
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Yeah they do- it's also worth noting that we all run water cooling on the turbos too, certain companies never bothered, which is utterly pikey in my opinion. Hence more demand on the cooling circuit, but less on the oil.
I have an ally rad on mine, which keeps everything super cool, no matter what ambinet :)
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Mine still has the standard fan and cowling too andy. But I do want to get rid of it for a slim line one for the reasons you say there. Just gives a bit more under bonnet space too
I stand corrected! For some reason I thought you had a slimline fan. Even when Yoof's car was on the stock rad with the slimline fan it never got as hot as mine on full ragging.
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I don't really seem to have any issues with temps on mine though, even on track days. Although it will get a bit warm doing 90 for ages on the motorway
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I don't really seem to have any issues with temps on mine though, even on track days. Although it will get a bit warm doing 90 for ages on the motorway
Does your gauge work :P :D
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Yes!
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After reading the experiences above I've given the rad fan & cowling a bit of attention lately, as I've noticed that mine too gets quite warm at motorway speeds on sunny days. I'm running the standard cowling and 2-stage fan and temps could get to 105*C relatively easily doing 70-80mph on the motorway. Are these temperatures similar for you Andy?
To check if the coolant system and rad itself was man enough for the task, I removed the cowling and fan completely and went for a blast on a warm day. I gave it a little stick and sustained 90-95 mph for about 15miles, but couldn't get the temp above about 93-94*C (as indicated on the clocks, not terribly accurate). Further runs at 70 and 80mph were similar, never more than ~97*C. Bizarrely about 75-80mph was hottest, I can only think that the increased airflow at greater speeds more than offsets the increased heat produced by the engine..?
I then torched the original cowling, adding Airflow AperturesTM where possible and refitted.
(http://i734.photobucket.com/albums/ww343/cheys03/Build%20thread/Turbo/7f30a990.jpg)
(http://i734.photobucket.com/albums/ww343/cheys03/Build%20thread/Turbo/64524695.jpg)
(http://i734.photobucket.com/albums/ww343/cheys03/Build%20thread/Turbo/78641ccb.jpg)
The results were quite positive, good enough to still keep the temperature down at idle, and a noticable difference at motorway speeds with a max. of about 100*C under similar testing. However, although a good improvement I don't personally see it as being good enough? and will be looking for a slimline fan in the near future.
Just wanted to share this testing really.
Please, if anyone has any recommended fan models, that would be much appreciated ;)
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Chris, did you get a plasma cutter for Christmas? ;D
Plenty of fans like this:
http://cgi.ebay.co.uk/12-inch-Genuine-SPAL-engine-cooling-fan-not-copy-/280678067654?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4159b76dc6
Available at cheap prices, from memory mine's 9" (my nob's much smaller), that does a fine job (the fan), but I've got an ally rad, so not really fair.
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Also bear in mind you'll have to get to 130'C+ before you start boiling the water ;)
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Ha! I wish! It's one of these (http://www.allplumbingsupplies.co.uk/Rothenberger-Tools-and-Equipment/Soldering-Brazing-Equip/Rothenberger-Portable-Brazing-Welding-Torch-Roxy-Kit-120L/prod_722.html) with the oxy turned up ;D I'm hoping to learn to braze etc.
I may just see how the coolant temperature gets in the hottest days of summer then, if the current temperatures aren't toooooooo much to worry about
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Chris, did you get a plasma cutter for Christmas? ;D
Plenty of fans like this:
http://cgi.ebay.co.uk/12-inch-Genuine-SPAL-engine-cooling-fan-not-copy-/280678067654?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4159b76dc6
Available at cheap prices, from memory mine's 9" (my nob's much smaller), that does a fine job (the fan), but I've got an ally rad, so not really fair.
sorry to jump on this, but is this pretty much a straight swap yoof or do you need some modding??
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Jake you'll need to sort the electrical connection and the fan mounts, other than that it plain sailing :)
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Cheers for the info yoof