Salmacis

iTrader: (1)

Thank you for the information, Mark.
It is a TD05H-18G, but I cannot get good power figures, hence I was worried it being an "fake".

ScoobyDoo69

iTrader: (17)

Running 10& Methanol is that not possible?

JamesF

I bought an 18g off Andy and traded in a TD05 I bought off ebay for £150, still saved over £300.

I agree that the 18g is more than you'll ever need for everyday driving. bhp isn't that important really it's torque you need to consider. An 18g will see you up to around 360 ft lbs with around 380bhp which I can assure you is plenty.

Yes, there are still times when I think I wish my car was faster but then I nail a 911 and all is well again.

I'm on a budget too so my flexible friend has taken the hit lately. Remember that it's not just a turbo you'll need, you may need injectors, fuel pump, spark plugs, better intercooler, exhaust system etc etc.

James.

R4LLY

iTrader: (1)

10% Meth does the trick.

Was rolling roaded at 420/380 on a hot day and didn't get close to target boost.

johnfelstead

Another interesting turbo is the Big16G, it produces stunning mid range performance but wont win you any power dyno awards. Mine looks like it's giving 380 Lbft and 360BHP, so if you are after mid range punch out of a corner and not bothered too much about top end, it's an option.

fireblade37

iTrader: (1)

So, if i change the 16g compressor wheel to a 18g its still not a 18g turbo?
Does this mean its not up to the job as say andy f's or zens 18g.
Has anyone else changed there 16g compressor wheel to a 18g with good results. I was thinking of converting my 16g in the not so distant future, not so sure now

JamesF

As far as I was aware AndyF's 18g hybrids ARE 16g's converted to an 18g with bigger wheel and housing. Perhaps I'm wrong but that was my take on it.

It would stand to reason as Andy accepts a 16g in exchange. Why else would he want it if not to convert it to something else ???

James.

johnfelstead

They use the same hotside and bearing core of the turbo, so a 16G will be needed to make an 18G on an exchange basis.

The confusion that can happen is whether an 18G compresor housing or a machined out 16G compresor housing is used, with the machined 16G housing accepting the bigger 18G compresor wheel. The compresor housing is the big alloy outer casting that the inlet pipe goes onto, the compresor wheel is the part that spins inside this housing, you can get 16G and 18G versions of both items.

So you can have a 16G housing/16G compresor wheel, 16G housing/18G compresor or 18G housing/18G compresor; the last two are both setups being called an 18G, which is why you have to be sure of what it is you are buying.

fireblade37

iTrader: (1)

Thanks john, that's helped my confusion.
The BIG 16g, whats involved in converting to one of these?

Anyone

johnfelstead

It's the same process as doing any of the TD05 conversions, this time using a larger compresor wheel than the standard 16G in a 16G housing. It's a half way house between 16G and 18G basically, it can produce a lot more midrange torque than the normal 16G and more torque low down than the 18G, it just wont produce the headline power of the 18G.

Mine looks like it's producing around 380lbft @ 4000rpm on a stock STi5 TMIC, it just wont pull the top end power to the same extent with around 360BHP. Thats with 1.7BAR boost. It makes for a really quick road car where you tend to use the torque a lot more than headline power. It needs something like an STi8 TMIC to be able to really push it harder especially at the top end, the turbo is capable of over 2BAR midrange, it's got quite a punch to it.

This is the Road Dyno plots of this turbo setup on my STi5 RA, with BRD EcuTek remap, still on stock injectors, standard air filter assembly, stock TMIC on a recently rebuilt 2.0 engine using STi9 crank, rods and STi8 forged pistons. Stock STi5 heads and cams etc. (running 8.3:1 compresion). It's just slipping the clutch right now which is why we stoped at 1.7BAR, you can see the slip in the middle of the power curve which is why it dips a little. Figures are at the wheels, not flywheel as seen on a rolling road.




If you want top end power it's not the right turbo for you, the 18G is better. If you want a torque monster for punching out of corners without the need to change much on the STi5 type of stock setup, it's worth considering.

johnfelstead

To give you a comparison, this is the Big16G compared to my previous STi5 RA with a healthy engine running the stock VF28 turbo, same TMIC etc and same mapper. (i wont use my previous setup on this car as the engine was tired, so doesnt give as fair a comparison).

dynamix

iTrader: (3)

Nice work JF

Are the TD range generally better than equiv IHI turbos?

silent running

Lots of good sense on here. John's absolutely correct about the different TD05 variants. To be even more clear, the 16G or 18G designation is always referring to the compressor wheel size (although to add complication the H that is often overlooked on the end of the TD05H model number means it has a doubled pattern of vanes on the compressor rather than 6 single ones radiating out.)

The MHI TD05s are rebuildable, the IHI VFs are not AFAIK. The 'big 16G' is basically a slightly bigger 16G wheel which can again be had in either a machined out 16G compressor housing or a larger 18G. So the lesson is, although the 'G' designation tells you what compressor wheel you have, you need to also look at the compressor housing that it's in. My understanding is that the larger the housing, the cooler the turbo will run at high boost levels, although there may be a trade off in efficiency at lower boost.

The point about firing out of corners using mid-range torque rather than outright top end power is well made. My TD05H-16G is mapped for 1.45 bar, probably making around 320bhp, and I took it to Cadwell Park last week. At first being as it was wet and I didn't want to cane the car too much, I knocked boost down to 1.0 bar to see how it went and tbh I ended up thrashing it very much as I would have done on a high-revving NA 16v motor, most of the time at 6000-7000 revs occasionally bumping into the limiter nastily, rowing through the gears pretty much all the time to keep it pulling well, often getting caught out in the wrong gear at the entrance or exit of a corner. Then after a few laps like this where it felt slow and I was only just keeping pace with Caterhams etc, I gave it the full 1.45 bar and the difference was like night and day - not in outright pace, but in driveability. Now I could leave it in gear through tricky corners and surf along on a wave of midrange torque. I don't think I ever bothered with any more than about 6000 rpm, it was plenty quick enough to outdrag most things on the straights and had the flexibility I needed in the corners to stay away from the gearstick and concentrate on the throttle.

Seems like that's what John got above with his 'big 16g'.

harvey

iTrader: (48)

Just a word of caution. There are plenty TD05-06 20G owners struggling to exceed 380 odd bhp. 18Gs are generally 20bhp behind that and again there are notable exceptions such as Martin Ninnybobs with 400 bhp on occassion but it does depend on fuel used and supporting mods.

Area 52 Autosport

That is actually incorrect. The 'H' has no bearing on the compressor wheel. The compressor wheel style is denoted by either a G, T or C. The 'H' refers to the turbine section only.


MHI turbos make for great hybrids simply due to the number of differing compressor wheels, turbine wheels and housings available. For example, for the 340-440bhp range we here have 5 different G style compressor wheels, 5 turbine wheels, 4 compressor covers and 3 turbine housings. This makes it easier to match the turbo to a particular application, whether it be 2L or 2.5L, low or high boost and anything in-between

Harvey also makes a very good point, just because you fit X turbo does not mean you will make X horsepower.... Not only do you need to view a turbo as a complete unit, but your own modification list can vary greatly as to the power curve you actually end up with.

Henrik

iTrader: (5)

This is true... I'm only on 353bhp with mine, due to e.g. a conservative map (I don't have and don't want any gauges, 2port boost solenoid etc).

Andy.F

Thats correct James. My 18G's have 18G housings, not machined out 16G housings.

Andy

JamesF

Thanks for clearing that up ANdy.

I'll speak to you again soon about getting booked in for another mapping session

James.