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caveo
Guest
jamiebennett81
Guest
yes i.e. too bigger compressor wheel, trying to flow too much for the physical amount of air the housing and turbine can cope with, leading to a bottle neck effect and then gasses building, temps rising and something has to let go
also leading to laggyness, with too bigger compressor wheel, and by the time the engine has enough revs to get it to spool, the turbine cannot cope and flow the air and its running out of puff and also you are prob running out of revs.....is how I remember it being explained to me I think
lag, lag, lag, boost, change, lag , lag.......and so on
jamiebennett81
Guest
Caveo, as I mentioned earlier in regards to lag, I think you need to consider a better suited turbo than that massive garrett one
ryan states about the preventative measures to stop it surging, but that is effectively dropping the boost....and dropping the boost means it will take longer to spin up the compressor, as he has said leading it to drive like a pig and be incredibly laggy
I think 400 on a well suited turbo, to get it to spool as soon as possible is the way forward
figures for pub talk remember. a gt28 or gt30 could be as quick if not quicker on the road than the garrett you are considering due to reaction and spool times
worth a thought perhaps.....
caveo
Guest
will look @ that mate after the internal work is done . Im i right going 1.9 or should i stay std bore ?
jamiebennett81
Guest
would going 1.9 be able to spool the turbo quicker then? due to more CC's allowing for more air to be pushed/flowed I presume?
caveo
Guest
Caveo, as I mentioned earlier in regards to lag, I think you need to consider a better suited turbo than that massive garrett one
ryan states about the preventative measures to stop it surging, but that is effectively dropping the boost....and dropping the boost means it will take longer to spin up the compressor, as he has said leading it to drive like a pig and be incredibly laggy
I think 400 on a well suited turbo, to get it to spool as soon as possible is the way forward
figures for pub talk remember. a gt28 or gt30 could be as quick if not quicker on the road than the garrett you are considering due to reaction and spool times
worth a thought perhaps.....
Absolutely.....the GT28RS on my car spins up very quickly from 2000rpm.....brilliant for the road and still good on track pulling to well over 7000 rpm.
Power is very respectable and want you don't want is big lag.....makes for a slower car all round.....
Another consideration is huge strain on the gearbox especially >400bhp
jamiebennett81
Guest
Absolutely.....the GT28RS on my car spins up very quickly from 2000rpm.....brilliant for the road and still good on track pulling to well over 7000 rpm.
Power is very respectable and want you don't want is big lag.....makes for a slower car all round.....
Another consideration is huge strain on the gearbox especially >400bhp
would you say 400bhp on the standard gear box is at it's limit then, and then strip a gear like hooch?
Backdraft
Guest
6 spd box's are good for whatever you throw at them. 5sps are as you know, crap. Only good for 350 max if you dont abuse them.
jamiebennett81
Guest
thats handy then, as the Leons are fitted with the 6 speed box
why are the 6 speeds good for high level power and the 5 speed bad?
also the TD** turbo's, these originate from early WRX models right?
found this as well, very interesting read on the TD turbos http://www.ztechz.net/id7.html
some very interesting points from the page too (if you can be bothered to read what I have quoted, but it's well worth a read)
Interesting read that if going down a hybrid route on a turbo, fitting a clipped and larger compressor wheel is not always a good idea. Because the compressor wheel is larger, it takes longer to spool, making it more laggy and making the turbo more peaky…
depends what you are after, but it could certianly explain the lazyness of my Hybrid gt2x and its lack of willing to spool as it should do
not sure on the comparison of spool times between a standard and hybrid gt2x though. I know Bill had some spreadsheets of another gt2x which was in standard form. Perhaps Bill could show us
anyway, the TD05 16g, with its quicker spool times looks like a nice option right now for road and light track use. The start of the surging on this graph sits outside the 3k mark, leading to decent spool up for a turbo this size
as where the graph for the gt30, a large proportion of surging sits inside the engine demand area
what I would like to see is a comparison of the gt28 and how the engine demand and surging compare to the TD05 16g, I suspect a very slightly later spool, but holding power harder and further up the range
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on std bore I would be hesitant on a GT30, more so on fwd. larger bore to help initial spool, then yea, probably ok..
too much power can ruin your drive.
gt2871 on octy is plenty capable of high 300's possibly touch the 400number.
with its 4wd it is spinning up in damp in 2nd gear under power. imagine yours under same conditions? - frustrating
a small a/r is key to the choice.
too big and nothing much will happen below 4krpm, and if you want to use the power and available flow you will need to rev it out.. (think valvegear here)
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jamiebennett81
Guest
just looking over costs again of internals (been told it's 2k cost)
can someone give me a break down cost of internals please
I believe it's only rods that are needed for around 380bhp, which is what I am looking to achieve. Rods I am told are around £300, so is it £1700 for fitting then
can someone give me a break down cost of internals please
I believe it's only rods that are needed for around 380bhp, which is what I am looking to achieve. Rods I am told are around £300, so is it £1700 for fitting then
That £2k price probably includes pistons and possibly valves. For 380bhp you would only want rods and possibly valves. I think you could do that for £1500.
and gaskets, head bolts, oil pump if high miler, and cam belt, tensioner and and and.....
On a recent job the parts associated with the head/pistons/valve fitment came to just short of £600, excluding labour. a 10 min job it is not. that excluded the main parts, rods, piston, head bolts etc as these were supplied earlier.
On a recent job the parts associated with the head/pistons/valve fitment came to just short of £600, excluding labour. a 10 min job it is not. that excluded the main parts, rods, piston, head bolts etc as these were supplied earlier.
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