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Turbo Setup

815 Views 12 Replies 6 Participants Last post by  Melmoth
I've asked this before but I can't quiet work out what sort of turbo I want to run.. For one I don't want to be spending an arm and a leg, the engine it's self has forged rods and standard Pistons. I'm not looking to aim any higher then 400bhp been looking at the td04 and td03 but unsure yet

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No one has any ideas then?

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I'd say a garret GT30 based turbo would be a good bet for 400 bhp
I was going to suggest one of those, but aren't they only good for about 350-360bhp (only, lol) but the op wanted around 400?

They are v cheap for what you can get out of them though :)
I highly rate my gt30, it just doesn't run out of puff like a small frame turbo does and you got room to grow. Plus Egt are much better
Thing is with big turbo, you get big lag. so if your 2wd...forget it. Your never going to get full potential of the turbo.

064 is around 360bhp/370lbft and get that from near enough the word go. Can get it to work well with 2wd aswell, but id recommend a diff.

Dont chase high numbers, Look at how the power is delivered and area of a power curve
Turbo lag isn't an issue unless you change gears at 4000rpm...

It concerns me the number of times I hear people complain about turbo lag and then talk of a better power delivery. If low end power band is what people are after, go diesel.

Otherwise consider this: when driving hard and shifting late, say 7500rpm, you will not drop below 4000rpm shifting up a gear, this is within the 'big turbo's' power band. So there is no turbo lag. By comparison on a small turbo you would be coming to the end of it's peak power band every time you shift towards the end of the rev range.

You are right about fwd being difficult to put power down though, which is why it makes sense to go big turbo as the power is up top as opposed to diesel like power delivery. So you will actually have better hope of putting the power down with a big turbo than a spikey small turbo that dies at the top end when the car stands a chance of putting the power down. I always found it fraustrating in my old hybrid turbo setup that the torque would plummet well before the rev cut and despite the smooth mapping I found traction to be a constant issue with the hybrid setup.
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I see where your coming from. But you have a big turbo that spools at ~5000rpm, who is going to cruise around country roads sat at 5000rpm, or go around a roundabout and boot it from 5000rpm? Yes lag will only be there for first time you stick your foot down, but I would rather drive a car with a nice spooling turbo with epic midrange, such as a k04-064 (you cant call this small spikey!) and have the best of both worlds. Full boost by 3000rpm and holding very very good numbers to roughly the last 1000rpm of your rev range.
I know I'm stating the obvious but you do not see top fuel dragsters ditching their 90mm turbos and clamming for small turbos. Same goes for track go-ers and drifters, although the reason is different for the latter, it is better to go big than small.

From what you're saying it sounds like a small turbo is ideal for convenience only, there's more to it than that, it is cheaper too so it appeals to a larger audience.

I don't think a gt30 is a big turbo, but mine on it's smooth slow spool map makes full boost by ~3800rpm, it can spool a lot earlier (going back for remapping soon) my peak torque and bhp is at 7450rpm
I don't think small turbos are for convenience it's more to do the fact that most people don't spend most of there time over 4k, big turbos make the car slow low down.
You can argue all day long which is better but it's what suits the driver, each to there own and all that, buy a huge dinner plate turbo get 6000bhp and be happy if that's what you like.
I personally hate the turbo lag on my k03s so god knows what a 'big' turbo would be like.
My old fiesta rst t2 turbo cut in at 1800rpm and had 190bhp it was wicked imo and also was way quicker than my golf up to 70mph
massive turbo and a 50 shot of NOS to spool the bugger. Everyone's a winner.
It really depends how big we're talking but having run hybrids and gt30 I've compared both print out at Bill's on the screen and there is nothing in it between my 500bhp gt30 on a slow smooth spool map compared with my hybrid setup. In terms of response it's 150rpm slower on the gt30, in my opinion worth the extra 200bhp.

And the really interesting thing is; even comparing the power on both graphs at 3000rpm I make more on the bigger gt30 than I did on the hybrid and that's before it really spools. The only time I found my gt30 made less power was around 2000rpm, for me it seems a worth while compromise to lose 30 odd bhp under 2000rpm to gain in the remaining 5500rpm because it may be lagging but it makes more power even while lagging.
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