Club G40 Forum
Technical => Turbochargers => Topic started by: G40 AD on November 10, 2009, 09:04:39 pm
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So want to know what turbos are good for a G40... it seems everyone uses the K03's... did fit one on a friends and just swapped it for a unit off a 200sx a garret jobby and its a hell of a lot faster and still doesnt have any significant lag... but as usual its off the road and i've not had chance to drive it yet... just trying to establish the plan for mine!!!
Also how do people find the comparison in actually driving... only been played with one being ragged hard... but how well do they spool up if you drop down a cog will it be back on boost pretty quick?!?!?
Cheers in advance...
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K03 spools earlier than a T25 as it's a smaller unit. A few of the guys using T25s run either stock cams or GT cams - i.e. big turbo and mild cam. With a K03 you need a lairier cam, otherwise it spools at 1500rpm and chokes up around 4500rpm.
K03 + 'turbo' cam = full boost around 3000rpm or so, peak power around 6000rpm - maybe slightly higher. There is lag compared to the G-lader, but not much - and it's lots lots more tractable so you waste less time/tyre tread wheelspinning.
On a stock bottom end with ported head and different cam I'd say both T25 and K03 will give you around 190bhp if you run enough boost. The T25 will be laggier though. In fairness to the T25, I'm not aware of anyone that's built one and had it properly mapped - so there's probably more in it given that it's a bigger turbo!
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aghh this sounds like some good quality advise, think i'm tempted to go lairy cam and little snail! although i fancy something different to the norm...
no intentions of ever getting rid of this so want to go all out and make it reliable too...
does anyone use the metal thicker head gasket (off g-laderseite) when turbo'ing, figured this would be a good idea to run "reliable" high boost...
do any particular turbo's have any relations with over heating as i've heard that the G's are a bit renowned for overheating once turbo'd... was planning oil cooler, lower temp rad switch, are lower temp thermostats available?
planning a front mount to fill the front bumper recess, slightly concerned that this will take away from the rads efficiency...
lots of Q's in there any answers much appreciated!
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What are K04's like compared with those 2??
cheers
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The metal HG is thinner, not thicker, so it raises the compression ratio slightly. Worthwhile on a stock bottom end. If you want to do something different to the norm, K04, K03 and T25 have all been done! The K03 is popular for a reason, as it makes for a very nice car.
If you hook up a K03's watercooling to the Polo system it can get a bit warm if you're holding it flat out on a dyno (or 'private road') for any significant length of time, but on track it wasn't a problem on Yoof's. We got Robin's up to 110degC on the dyno at one point, but that was repeatedly getting up to and holding ~130mph road speed with a fan only simulating 40mph airflow.
Ideally a bigger radiator is needed. It's not just down to the turbo though, you're now making say 190bhp with a cooling system spec'd to deal with 113bhp - so there's a lot more waste heat to deal with!
With a purely oil cooled (and lubricated) turbo you're dumping the heat into your oil system, so you'd need a massive oil cooler instead.
I've not personally tried a K04, but given their price (for a genuine one, not an eBay Chinese 'K04' K03-copy with stronger actuator spring) a GT25R is an alternative - one that we're going to trial in Yoof's car.
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is a seat terra radiator bigger would this be a good upgrade for the rad?? what else can be done for the overheating problem ??
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there is no overheating "problem", mine currently doesn't even have a g40 spec radiator on it and it manages to keep temps down OK. Diesel mk3 polos had bigger radiators, not sure if the same one was used in a terra van or not.
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hayesey - by mk3 does that mean a mk2f or 6n? if mk2f i've never even seen a diesel!!!
- what bhp/set up & cooling systems are you running?
just a thought... would a standalone system for a water cooled turbo help on the cooling battle?
was thinking i could tuck an oil cooler and a turbo cooler^^^ behind the front grill...
front mount to fill the bottom bumper recess and standard rad in near enough standard spot...
are the rothe manifolds designed offset to oneside for clearance? or possibly to help with alignment for FMIC's?
it seems odd to me otherwise and they look very restrictive (or not smoothly flowing).
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I'm using a k03 and have all the water cooling plumbed in. It made 194bhp at the recent club g40 rr day.
yeah I mean mk2f, diesel ones are only generally found in mainland europe, rads are available though.
I'm using a standard radiator & a small oil cooler.
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have k04's actually been done by anyone on here?
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hayesay is that small oil cooler enough , i currently have a small oil cooler not sure to when i fit the turbo to go to a slightly larger one ?? what kinda oil temps should you be looking at ??
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have k04's actually been done by anyone on here?
Only person i know of thats done it is Jay Mac. He doesnt get on here really but he did it to his mk1 polo. Not sure if he has it anymore though been up for sale quite awhile!
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Don't think it had been mapped properly afterwards though, so not really a fair comparison.
As Robin & Hayesey will testify, there's worlds between a turbo bolted on and a properly mapped one. Infact I'm so surprised by the level of drivability Andy managed to get out of them, I'm considering ditching the 172 and building a 150bhp daily driver G40 Turbo- they're like a GT on steroids ;D
The rothe manifolds flow enough gas for 225bhp- so should be fine for most K03 applications, I really liked my K03 and hope the GT25R will give enough of a power increase, otherwise I'm ditching all the bits and refitting a K03!
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A good compromise betwen a straight T25 and K03 is a Garret turbo off a Saab. I believe it is the GT1752. Same spool as a K03, and capable of slightly more bhp. Can run a "ebay" T25 manifold too
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Someone tryed a K03 with a 3F cam on wich RPM it spools? ???
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A good compromise betwen a straight T25 and K03 is a Garret turbo off a Saab. I believe it is the GT1752. Same spool as a K03, and capable of slightly more bhp. Can run a "ebay" T25 manifold too
The man speaks the truth. Gt17 off a saab 93 non aero.
Ive got a 200SX S13 turbo on mine but with a .49 AR turbine housing instead of the .64 one.
The S14 turbos have a bigger compressor wheel, but its a bit too big really.
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LPT Saab 9-5s use the same turbo too.
Be careful though, the 9-5s have sump sludge issues - which best case starve the turbo of oil and kill that, worst case kill the cylinder head and later the engine if you leave it long enough. So check out whatever you're buying first - even if it's off a low mileage car you know.
Would be interested to see the results of someone trying a GT17. On the 2.3l 16v Saab lumps they max out at 240bhp - compared to 220bhp for the K03-005 on a 1.8l 20v motor. If I get my hands on one cheap enough then we'll try it on Yoof's car for a proper K03/GT2554R/GT1752 comparison.
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Someone tryed a K03 with a 3F cam on wich RPM it spools? ???
It'll spool at about 1800rpm (vs about 1500rpm on a G40 cam) and start to choke up at 5500rpm if not before. Ideally you need a lairier cam than a GT one.
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have k04's actually been done by anyone on here?
Only person i know of thats done it is Jay Mac. He doesnt get on here really but he did it to his mk1 polo. Not sure if he has it anymore though been up for sale quite awhile!
The one on Jay's Mk1 G40 turbo was an eBay special Chinese-copy of a K03-005 with a strong actuator spring. Exactly the same type of turbo that Yoof killed at Oulton Park about a year ago.
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Where would you get a g40 manifold to fit a gt17 and could you use the same cam as the psd ko3 one ?? I looked on eBay for a t25 one and couldn't find any am slightly tempted to try this rather than the ko3 as it may produce slightly lower charge temps, I assume I would need to get A custom downpipe to suit or maybe one from emtec designed for the t25 turbo that they do with there kit hmm would be intresting maybe a little safer aswell especialy for long motorway drives.
What would be the advantages of running the piggyback ecu set up you where talking about andy improoved economy around the 15psi setting I was thinking of and could have a more specific map for the 21-23psi boost ??
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he's not talking about a piggyback ecu, it's an adaptor that allows you to run two maps on one (twice the size) chip and switch between the two. A piggyback ecu is something different.
Where would you get a g40 manifold to fit a gt17
well that's been exactly my point all along! People use k03 because it works, it's proven to make 200bhp reliably and can be done with cheap (ish) off the shelf parts. Plus since so many people have done it there's loads of info. Using other stuff you're going to have to make a lot of custom parts and figure things out for yourself. From what I've seen of yoof's emtech kit it isn't all that great.
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Hayesey is correct- the Emtech kit requires some chopping and moving of oil cooler, and I'm having another downpipe made as the one with it fouls the block.
K03 is a good turbo for the 1341cc- anyone who says it's too small hasn't driven one- or been out in a properly mapped one. A proven 193bhp on a 1341cc stock head, or 1272cc with BV head, or 203bhp with 1341cc and bv head.