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Discussion Starter · #1 ·
Further to my blown turbo problem (9000 thread), does anyone know if the specification of the TD04 fitted to manual 9000 Aeros was ever changed?

ie. would a unit from any year fit my '97, or do I need to watch out for differences?

Carl
 

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There are 4 basic TD04HL-15x 6cm2 turbo's, 2 with equal height impeller blades and 2 with unequal height (alternating)

The 9000 Aero's used both of 1 type, possibly 1993 for one and 1994-1998 for the other.

I'm not too sure of the differences though, but the models used were TD04HL-15G 6cm2 and TD04HL-15T
6cm2

The 9-3 Viggen used a 5cm2 for faster sppol up, but it impacts top end power (due to the 5cm2 restricted exhaust opening.

From a helpful web site
All MHI wheels I have seen have 12 blades. Blades are always evenly spaced, but the pitch and height of the blades can change between models. "B"- and "C"-style compressor wheels have all blade tips at the same height. "G"-, "Gk"-, and "T"-style wheels have blade tips at two heights, alternating high and low.[/b]
Andrew
 

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Discussion Starter · #3 ·
Well I'm learning more than I thought I wanted to about TD04s...

So Aeros always had the same performance figures quoted, but in fact had detail differences over the years, including different turbo vane designs?

On the basis that the exhaust downpipe fitment and manifold designs never varied, I take it that I could happilly fit any of those TD04HLs, be it a G or a T spec?

Does this also fit with people's reports of earlier cars being more brutal than later ones? ie. does a G spec TD04 have a more agressive spool, perhaps?

Carl
 

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watch it there are other factors in the "brutal" argument
earlier cars had a different head as well as a few other things
I know the earlier carlsson's have a brutal power delivery and that is with the smaller turbo.. this is probably down to the ecu
so the detail has changed over the years
which is better ?
you would have to have access to SAAB's dev results to know ..
My guess there will be a little difference spool up,sustained pressure ability ...but in the greater scheme of things other factors will make more of a difference
If you can get a cheap one ....slap it on !!
 

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Originally posted by ylee coyote:
[qb]watch it there are other factors in the "brutal" argument[/qb][/b]
It could also be down to the lower compression ratio on earlier engines, which could mean slightly poorer off-boost performance with consequently greater lag and more sudden onset of boost when it does happen.
 

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Discussion Starter · #8 ·
Hehe.

Thanks everyone - the worry about compatibility is over, as I took delivery today of a TD04HL-15G.

Yes it was cheap.

Yes I've (mostly - it started to rain) slapped it on!

Brand new Saab part (ie NOT recon) for £300, and no need to return my old one to them (so I might have it rebuilt as a spare yet) - feels like a bargain so far, but I'll let you know tomorrow (if the rain stops).

I've taken some photos for camparrison of the T-spec I took off to the G-spec I put on - and yes, the vanes are visibly different.

Carl
 

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Discussion Starter · #10 ·
So the new turbo's on - though it took longer than it might have when the centre exhaust box / resonator fell apart with all the jiggling as I waggled the downpipe back into place...and I had to cut the pipe between the resonator and the joint with the back box because the bolts had seized (which then also had to be cut off) before I could fit the new one (courtesy of my donor-car) - so there went another day!

But the car's now back on the road and tight as a drum - I just need to wind a couple of turns off the base boost to set it up properly, and I can wait for the next project.

But for now, here's some pictures:

Firstly, the old and the new:



You can see that the new has an extra mounting point cast into it, and a different position for the boost pressure take-off.

Then, a closer (sorry about the quality) view of the G vanes:



Where you can see that there are two sizes of vane, each following the same curve outwards.

But looking at the T vanes:



The vanes are again in two sizes (despite what I read in several places online before seeing it for myself), but this time the bigger ones are straight edged, and the smaller set curve in towards their partners, with each pair forming a sort of flattened half-elipse.

Something else to note is that I took a chance on the turbo in order to get the cheap one (figured I could always ebay it), as it was not specified as a 6cm2 as it should have been (TD04HL-15T-6 or TD04HL-15G-6), but instead carried no designation (TD04HL-15G). I bought it assuming it would be a 5cm2 (Viggen and 9-5 Aero spec), and that that would be fine too, as it gives lower-boost urge at the expense of top end power, and that's sort-of how I drive. In the event, it's clearly marked (cast into the metal) as a 6, the same as the one that came off.

When I've got the boost set correctly, I'll let you know if there's any difference in the driving.

Carl
 

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Carl, if you don't mind, is it possible that you could measure the inducer and exducer diameters (if you have calipers) of both compressors? I'm not sure about the 15T & 15G, but it seems that the difference between all other T & G's is that the inducer and exducer diamteters (and perhaps the diameter of the compressor turbine?) is slightly larger on the T's.....or, if anyone knows the answer to this, thanks in advance!
 

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Discussion Starter · #13 ·
I wouldn't mind taking the measurements at all, except I don't have calipers - sorry.

As far as differences go (and I know it's hardly scientific), I spent some time comparing the two in good light and with a metal mm rule to convince myself the new one was going to fit; and the photos are as they are because they show the only appreciable differences - if any changes were significant enough for me to notice, I would have photographed them too.

As to the driving; now that I have the base-boost set, the car is flying again. It's difficult to be precise about what is only a seat-of-the-pants rating, but I'd say the G spools earlier and the boost doesn't so much tail-off at high revs as reach a level at about 5000rpm, where it used to keep climbing (or be it at a reduced rate).

For the meat of the power delivery between 3000 and 4500rpm, it feels just as before (rather good), and seems to be giving the traction control less to do, too - again, difficult to be sure, as the roads are more dry and warm than when I last drove 'properly' before the breakage(s).

I have also changed the DI pack, which has removed the lumpy boost (confirmed by running new turbo with old DI pack to check) and replaced the exhaust centre section - you have to think those two items must have been influencing performance even before they became noticable.

An added bonus (for me, anyway) to the exhaust change (which involved replacing a resonator with a cheapy conventional silencer) has been the addition of a lovely C900 T16S burble from the rear, which has had me driving with the window down.

Induction noise + waste gate whoosh + burble from the rear = happy me

Carl
 

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looks as if you got a real bargain there

you can get your old one remade into a 18t or even a 19t now....


I do not know if it is just the angle but it looks as if the exit pipe is longer on the new one
interestingly they have moved the pressure take off..you can see there are a few places where it can be sited

all in all
 
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