Cost of going BT and parts needed?

[ryan_s3]

you can help surge by restricting the spool of the turbo so you give the turbo time to turn the large compressor unfortunately it then becomes laggy and a pig to drive!

 

[caveo]

450 max me thinks , ill aim higher but if iv learnt owt its you dont always hit what you want .

 

[ryan_s3]

caveo,400bhp mega quick spooling is what you want,trust me!Look at the above graph which do you think is quicker on the road?

 

[jamiebennett81]

surge is down to a mismatch of comp to turbine wheels or housing size ,capacity or any resriction

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

 

[ryan_s3]

Have a word with hooch and bill but i'd like the idea of a gt3071 0.63 housing on a 1.8t with decent manifold.Let us know what you go for mate.

 

[jamiebennett81]

you can help surge by restricting the spool of the turbo so you give the turbo time to turn the large compressor unfortunately it then becomes laggy and a pig to drive!

450 max me thinks , ill aim higher but if iv learnt owt its you dont always hit what you want .

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]

caveo,400bhp mega quick spooling is what you want,trust me!Look at the above graph which do you think is quicker on the road?

will look @ that mate after the internal work is done . Im i right going 1.9 or should i stay std bore ?

 

[jamiebennett81]

will look @ that mate after the internal work is done . Im i right going 1.9 or should i stay std bore ?

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]

I'v seen some peeps wanting to reduce bore ....why?

 

[Ianb]

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]

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?

 

[h17och]

you mean alex...

 

[Backdraft]

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]

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.

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

 

[ibizacupra]

what would you recommend Bill, gt28 or gt30 for around the 400bhp mark comfortably?

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)

 

[ibizacupra]

the turbo will want to flow more than the head can maybe?

yep, and surge can then occur.
think flow & boost not just boost

 

[jamiebennett81]

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

 

[pj1985]

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.

 

[INA]

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.

Installed?

 

[ibizacupra]

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.