john banks

A P20 housing can be machined to accept a TD05H turbine wheel and can then be attached to a TD05H core.

The AR should increase from about 0.50 to 0.71. Bear in mind that the TD05 wheel is considerably bigger than the IHI wheels and this could produce a nice bolt on hot side to go with a 20G?

http://www.turbofast.com.au/GTseries.html

From only changing the AR of the turbine cover on the above Garretts it appears that a 10% gain in power is possible at the expense of spool up, although this would suit a larger compressor like the 20G.

Comments?

[Edited by john banks - 17/04/2003 23:04:52]

Pavlo

go on then!

pat

It probably won't solve the compressor surge issues

[Edited because the smilie syntax is different on SN, and the syntax page is totally 404]


[Edited by pat - 4/18/2003 2:22:05 AM]

john banks

Do you think the hot side needs to be even bigger then Pat? I do want some action this side of 4000 RPM if possible Remember I only have issues in the two top gears... 0.21 AR increase could be substantial?

pat

John,

I was alluding to the fact that any change in exhaust A/R ratio would only bring about a minor difference in VE, ie not enough to suddenly make the engine consume enough air to avoid the surge issue. Of course the reduced spool up may mean that it is no longer possible with an EJ20 to produce the boost at lower revs and avoid the problem that way, but the 0.5 A/R housing is good for over 400 BHP anyway, so going to a 0.7 would only make sense to me on a larger displacement engine.

The issue with the 20G is its surge line, and nothing that you can do with the hot side will alter that, it can only help you avoid it, not move it to a more favourable area of the map.

Cheers,

Pat.

john banks

It is obvious that it will not change the surge at say 1.5 bar and 3500 RPM if it still makes that, the intention was for the larger capacity engine to not waste top end EGBP because of a hot side which is small enough to cross the compressor surge line. Since the turbine flow tends to quickly top out once the PR across it gets to a level, then just because the TD05H 7cm2 hot side will do c.430 does not mean it will do 450 BHP easily whereas the 20G wheel should.

Since some/all/most (?) turbos that will flow ballpark 700 CFM don't make full boost until 4500 RPM or so anyway because of the exhaust sizing then why not enlarge the exhaust side a bit? Note that 0.21 on the AR is about double the sole difference between a VF28 and a VF23 (P18 to P20).

The issue to me seems less the 20G wheel which has a compressor flow map as wide as a lot of the Garrett GT wheels (particularly the ones that fit in sane sized housings), but more that the TD05H is able to surge it for 1000 RPM in the top two gears.

I suppose the mythical 18G would be good for lower power applications with the standard TD05 hot side, G implies it does have the two levels of compressor blades, but there is very little info on it, and it would not flow 700 CFM.

With the 20G we have compromised on the exhaust side. Some others are compromising on using compressors in housings for which they don't have flow maps, so it is all a bit of guess work.

Looking at http://www.turbobygarrett.com/turbob...sp/catalog.pdf and the Ray Hall site for differences in flow/power for different compressor or exhaust covers with the same wheels was enlightening to me anyway.

Of course I want my cake whilst eating it

[Edited by john banks - 4/18/2003 10:44:53 AM]

dowser

I think you should try it and publish the results, lol! I'll be starting my ej25 on the stock td05, and then playing with the spare one's compressor only. If a better solution for the exhaust side could be found, it would be nice

Richard

john banks

Thought I'd offer it to the Drivetrain lions to chew on for a while before I spend my cash Some have chewed and tasted, some are still to do so, let's see if they like the flavour first

TD05H 7cm2 AR 0.50
P18 0.63
P20 0.71

So this would be about 2.5 times the difference in AR between the P18 and P20.... how many hundred RPM difference in boost threshold between P18 and P20 have you guys seen? 200RPM? I'm not saying you can just linearise it and extrapolate but it might give us a ballpark?

[Edited by john banks - 4/18/2003 12:38:53 PM]

Mike555

If I have a TD05 and want to put it on my car, but my wishes are as less as laggy possible and 360 bhp is good enough. Which combination is the best???

john banks

The standard TD05 with its original exhaust housing (obviously with the work on the compressor cover to fit your car).

Mike555

John,

Can you tell me the spec of the standard td05, at wich rpm is it on full boost let say 1.4 bar.
And where can I make it front entry and how much.

Thanks a lot

Mike

john banks

Standard TD05 on my car was hitting 1 bar at 2700 RPM in 5th gear or 3000 RPM in 4th gear. If you held it back on the brakes in 3rd gear you could get 1 bar at 2700 RPM.

There are various options to get it converted to front entry which may or may not include rebuild and balancing depending on what you are prepared to shell out.

Suggest you speak to Mark at Lateral Performance.

[Edited by john banks - 4/19/2003 10:56:38 PM]

Mike555

I can get a TD05 for 277 pound, has less then 10000km. Is this worth to buy it??

Regards Mike

john banks

A bit expensive, although it is so low mileage you shouldn't need to overhaul it so maybe it is worth it. You still need the front cover sorted.

Mike555

What size is the stock TD05 at the exhaust side?? 14g, 16g

john banks

7cm2.

MorayMackenzie

John,

"I suppose the mythical 18G would be good for lower power applications with the standard TD05 hot side, G implies it does have the two levels of compressor blades, but there is very little info on it, and it would not flow 700 CFM."

How can the 18G be mythical, implying non existant, and yet you can state categorically that it wont flow 700CFM? On the one had you are saying you don't know anything really about it, on the other you are making a sweeping statement about its capability... I am assuming that, as even the guy who aluded to having seen a compressor map for it didn't respond to my request for any info on the map that there isn't much about it in the public domain.

Moray

Pavlo

Mythical?

I have an 18g compressor map somewhere I am sure, because I remember deciding that the big 16g was possibly better than the 18g based on the compressor maps.

Paul

MorayMackenzie

PS: IIRC, Andy F seemed to imply that the 18G didn't have the two sets of vanes you allude to. Personally, I suspect that it does have the same fin design as the 20G.

MorayMackenzie

Great news re the map Paul, I was of the opinion that it (18G) existed anyways, John seems to have the belief issue.

I was, however, beginning to give up hope of seeing a compressor map for the 18G. I would very much appreciate the chance to have a look at the 18G map please, any chance you could forward me a copy of it, pretty please with the sweetener of your choice on top?

Moray
(fingers crossed)

john banks

belief issues, not saying it didn't exist, Greddy use loads of them, just that none of us have found compressor maps in the public domain, if Paul can oblige I am sure we would both be delighted. Maybe mythical was the wrong word and mysterious would be better. I have seen it quoted as 600 CFM though.. http://www.google.com/search?sourcei...t&q=18g+600cfm

Other info suggests the 600 CFM is at PR 2.0 (compared to 640 on the 20G). The exducer is the same size as the 20G but the inducer is smaller with a trim of 55 (compared to 60). The big questions to me are what is the surge line like and can you get another 40-50 CFM out of it on an EJ20 than its PR 2.0 rating (which will depend on how fat 60% island is above that pressure).

The reason I thought the vanes were on two levels was because of the "G" which is the MHI notation for this sort of wheel. There are also the occasional good few reports with them being used including one or two on NASIOC, but not enough hard data. I think Andy F had seen a picture of what was said to be 18G but it had one level of vanes.

http://www.stealth316.com/2-turboguide.htm :
" "B"-, "C"-, and "T"-style compressor wheels have all blade tips at the same height. "G"-style wheels have blade tips at two heights, alternating high and low. Blades are always evenly spaced, but the number of and pitch of the blades can change between models."

I think it could be great on a 2.0 at sane levels of top end boost.

Think the big 16G could also be good - for higher boost applications it flows more efficiently and to high PR than the small 16G, and as a bonus the surge line is further to the left - I used to get a little flutter out of the 16G if I overdid it before 4000 RPM.

[Edited by john banks - 4/23/2003 11:45:50 AM]

[Edited by john banks - 4/23/2003 11:52:12 AM]

Pavlo

I have no idea where an 18g map is right now, and now am also having belief issues!

will check it out and report any sightings

Paul

carlos_hiraoka

Moray what turbo are u using ?????

john banks

Pat used to have a TD05-18G I wonder if he would comment further on what it did? Do you have this turbo now Moray?

[Edited by john banks - 4/23/2003 5:15:33 PM]

MorayMackenzie

The turbo Pat had on his car was a TD05/06 18G hybrid that was originally supplied to him absolutely ages ago by Mark, in the days before Lateral performance happened. Pat has moved on to a larger and more silly ( ) project, and I am lucky enough to be providing a new home for this cute little biddy turbo.

john banks

So how does it perform? Would love to see some boost curves and power/torque curves. When you say /06 hybrid do you mean that you are using the 20G compressor cover (thought it was too big?) or the 05H cover?

[Edited by john banks - 4/23/2003 6:29:15 PM]

carlos_hiraoka

some nice turbo Moray has been hiding under his hood

john banks

MorayDarkHorseWithANiceTurboMackenzie TellUsHowSheGoes

MorayMackenzie

John, In the nicest possible way , I'm not interested in getting drawn into yet another childish tribe based "my turbo does this and this and this better than yours" type of bunfight, _if_ that's where this is going. Assuming this is not going such a way...

I am still trying to find a compressor map for the 18G wheel so I can get a better idea of what boost targets etc I should be using where. As it is, the pectel map is still a work in progress and I am keeping boost conservative until we iron out the crank/cam sensor interference issue, which is just a case of finding the time to reroute the signal wires, maybe this weekend coming.

Suffice to say, the turbo had Pat and myself in fits of giggles as we mapped it on the motec, and that was with narrow band lambda and motec capabilities, consequently I am expecting many more such giggles shortly.

john banks

Sounds good. I'm not into tribal warfare and share any info I have. I am very interested in where the 18G could be more user friendly than the 20G. It could well be more suited to a 2.0 litre, that is all I'm trying to canvas from you