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Discussion Starter #1
Mark E had posted this info in a previous posting
quote:
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I’ve had two hybrids on my 2.3fpt. The first was based on a GT30 and definitely gave better response than the standard unit. However even with a 360 degree bearing the seals gave up after a couple of years of hard driving and at that point I moved to a T3/T28 hybrid with roller bearings, comfortably rated for 350hp.
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I'm in the process of trying to get a ball bearing hybrid for my 2.3 Carlsson. One specialist says I need a GT 28 Series good for 320-360hp another says I need a T25-T28 with a .64 exh housing and a .42 or .6 or go to a 0.8 T250 compressor housing, another says I need a T28 with a .64 housing as fitted to 4x4 Cosworths.

To say I'm confused is an understatement. I want a ball bearing turbo which is a straight swap if possible which spools up fast and can give me 2 bar without running out of steam. I'm running 1.6 at the moment but life expectancy of the standard unit is low....probably measured in minutes!

Anyone offer any advise on what turbo I need to fit and who can supply it. As I've been quoted between £795 to £980 +vat I want to make sure I am buying the right turbo for the job.
 

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Mark,

Myself and paulmanchester have been asking a similar question here

We didn't have much joy, personally I'm going for a used TD04-15T. My ultimate target being 300bhp and as little lag as possible. Is your car holding 1.6BAR? I guess you must be c320bhp at present, but on the original T25?
What's the spec of your car, IIRC you have fast cams and a balanced crank? If you've got a custom APC I'd be interested to know where you got it from.
 

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2.0 bar (!!!) on a 2.3 engine definitely sounds in GT30BB (as supplied by Map Tun with Stage 6 ) territory. Personally, I'd consider easing off a bit on the turbo boost front and go for a GT25BB which should be available for both T25 (yours) and T3 bolt patterns for driveability. The GT25BB is good for up to 350 hp as per Garrett, the GT30BB will send you into the 400s with the proper hard/software...
 

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Discussion Starter #4
I'm running a standard internal engine at the moment, my fully tuned engine is under the blue cover at the front of my scrap car on a pallet!
I have a gas flowed head, 3" JT exhaust, no cat, Aquamist running 50% methanol, modded airbox with JT filter, mbc plus minor other mods on this engine. No custom apc, not for the want of trying though, I've emailed all over the place.
Although this engine isn't built for the hp I am after I have the above engine that I might stick it on in the future so thats why I'm aiming for the higher boost rating.
With super unleaded it holds 1.6 bar but I do go easy as I need to get the fuelling checked on a dyno...
I'm just confused as why when I asked 4 different turbo suppliers I got 4 different answers.
Giles of Turbotechnics is back this week, I might be looking at answer no 5!
Keep the info coming.....I'll have to bite the bullet soon
 

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All I can say is that the Garret gtbb30 has a lot of er ..lag but it also has a lot of puff
When I was sold the stage 6 and I enquired at Garrett they convinced me that lag would be less for a bb turbo
All things being equal yes but its got a fecking huuge compressor on it !!
so it does take a little time to get going !
(even with a lightened flywheel !!)
however it is good for 550 hp

I will be asking maptun to modify my map to give me a little more "tractability " at low rpm's
 

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No custom apc, not for the want of trying though, I've emailed all over the place.  [/b]
I've just started, but that doesn't sound promising. I've e-mailed SQR and Swedish Dynamics with no response as yet. It seems nobody wants to touch the Jetronic/DI/APC cars as it's easier (i.e. more profitable) to do the "one box" upgrades on the Trionic cars.

Back on topic ... is there a roller bearing version of the TD04?
 

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Originally posted by ylee coyote:
[qb]All  I can say is that the Garret gtbb30 has a lot of er ..lag but it also has a lot of puff
When I was sold the stage 6 and I enquired at Garrett they convinced me that lag would be less for a bb turbo
All things being equal yes but its got a fecking huuge compressor on it !!
so it does take a little time to get going !
(even with a lightened flywheel !!)
however it is good for 550 hp
   :eek:      :eek:      :eek:      :eek:      :eek:  
I will be asking maptun to modify my map to give me a little more "tractability " at low rpm's [/qb][/b]
IIRC the MapTun stage 6 is 440hp. A nicely setup GT32BB (71mm compressor instead of 76.2mm) should flow right up to 440 hp, and should have considerably less lag.

However should you want 550 hp ceramic coated pistons, exhaust valves, exhaust ports, and headers will all significantly improve spool up. They should also make all of the previously mentioned parts last longer under high boost as well. But at the expense of your wallet.

Dubbya~
 

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Having had the "BB" experience, I'd advise caution. My understanding of the reason for using BB turbos is that they allow bigger compressors to be used without incurring major lag penalties in the midrange, thus allowing higher flow rates. However, they will still be more sluggish lower down that a smaller turbo.

My turbo specialist, Turbo Developments ( 0208 560 3927), agrees that the lack of lag in midrange cause problems for many software mappings that can't "keep up" with the rate of boost rise. Other customers have had similar problems with Cossies etc.

I still haven't been able to solve my problem of overboost, even with Maptun custom stage 5 software. Part of the problem is certainly down to the fact that my MAP sensor (MY93 Trionic) is only good to 1.65 bar (at this point the pressure signal in Trionic is 255 out of a possible 255). The software runs a peak boost of circa 1.6 bar, so it's right on the limit. The practical effects of this are that it can swing up to 2 bar boost.

The problem with this is that you're then entering into an unmapped area for Trionic, and it's probably still fuelling for the max 1.65bar. Not good.

I would love to try it with a 3 bar MAP sensor, but there doesn't seem any way to do so. I've tried a couple of times to make a phsyical boost presure limit but haven't yet succeeded. I think I might need to use poneumatic control valves and the like.

Later models of Trionic (MY94 onwards) can have a 3 bar MAP sensor fitted, and I would guess they will cope.

However, I get the impression that the software needs to be slugged to avoid overboost, which probably results in more lag lower down.

Given the power of Trionic, with hindsight I wish I had talked to the tuners (Maptun) about my choice of turbo beforehand- but the two events were some 6 months or more apart. I think that would be my recommendation to anyone else considering the upgrade path.

Maptun suggest a TD04-18T for their Stage 5; I would suggest you could do a lot worse that use that.

[edit] Doh! I forgot yours is a Carlsson and therefore DI/APC. However I think the relevant comments still stand-
a) You need to be careul of the lack of lag with a BB turbo and match software to it.
B) You need to have a system that can cope with the fuelling requirements. I dunno at what point the AMM runs out of flow range?
 

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Originally posted by Mark E:
[qb] I dunno at what point the AMM runs out of flow range? [/qb][/b]
Shouldn't matter too much with LH, as AMM input is disregarded when on WOT - at least from a certain RPM onwards - anyways. As soon as the trottle position switch (2.2)/sensor (2.4 upwards) detects a WOT, fueling is completely reliant on the embedded fuel map and fuel pressure.

The AMM in Bosch LH-controlled c900's and the equivalent 9000 models reaches its maximum 5V output at an airflow rate equivalent to about 230 hp, which I think should suffice for all non-WOT situations. I don't know about the AMM used in 2.3 litre 9000 models. For all intents and purposes, it could even be the same.
 

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LOL That intercooler flows 900+ CFM @ a 1 psi pressure drop. Even the BIGGEST turbocharger would never require that amount of flow. Remember every time you double the pressure, you cut the flow in half. Here's a little help on intercooler sizing before you go and destroy your wallet!

To convert flow rates of turbo maps from Garrett into CFM multiply the lb/min by 14.47.

Let's use ylee's huge GT30R as an example. It flows as much as 50 lbs/min. If he runs 1.6 bar ...

50 lb/min x 14.47 = 723.5 CFM @ ambient pressure ...

However now this air is compressed to 1.6 bar above ambient. This gives a pressure ratio of 2.6:1 ...

723.5 / 2.6 = 278 CFM

You can't go wrong with more flow, OR more surface area. A bigger intercooler will cool a little better. But one as huge as Mark in Ireland linked that Mr Yankton used is WAY bigger than you could ever need. I believe it's along the same lines size wise as Per Eklunds hillclimb car!!


For some smaller, and more economical choices try Bell intercoolers:

http://www.bellintercoolers.com/

Here's a nice one:

3.50 inches thick, 9.40 inches tall, and 18.00 inches wide, flowing 290 CFM (which would give you less than 1 psi of pressure drop @ 550 horsepower!) and weighing only 11.60 lbs. Cost: $333.00 + $100 or so to have someone TIG weld or Braze some end tanks for it! I'd say that's a pretty good deal!

Dubbya~
 

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Discussion Starter #15
Turbotechnics don't do BB turbos! Reckon the reliability hasn't been proven yet. Awaiting more info on a normal bearing turbo from them.
 

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Mark,

At the risk of stating the obvious, I presume you are specifying a 360 degree thrust bearing for a non BB unit- this is necessary for longevity at higher boost pressures.

Seriously, I'd give Turbo Developments a call- the guy there really knows his stuff and has supplied others apart from me. You will also talk directly to the horses mouth, rather than a sales guy.
 

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Discussion Starter #17
I've spoke to the girl there but she asked me to send an email with what I want and they'll get back to me. She said initially a T28 and it'll cost £1100 +vat
...when I asked for a breakdown on sizes etc she asked for the email.
I'm awaiting a response.
At the risk of stating the obvious, I presume you are specifying a 360 degree thrust bearing for a non BB unit- this is necessary for longevity at higher boost pressures.

 [/b]
Yes, but they said there are 360 deg bearings and 360 deg bearings!! Some are better than others. I thought the ceramic bearing would be the best but I'll find out soon no doubt.
 

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Discussion Starter #20
How does this sound...
1. 48 trim, 93865S specification TO4E 76mm high flow compressor wheel with 53mm inducer diameter.

2. 0.70 A/R compressor housing with 3 or 4-inch diameter inlet & 2.5 inch compressor discharge for maximum air flow capability.

3. Left hand threat shaft with GT28 series 76 trim ‘low inertia’ Inconel turbine wheel, fitted with a racing ‘Staggered Gap’ total seal ring to stop oil seepage caused by large bore or low backpressure exhaust systems.

4. Modified bearing housing fitted with angular contact twin roller bearing cartridge for maximum thrust load capability and fastest ‘spool time’.

5. Specially modified turbine housing, 0.61 A/R with ported & polished inlet throat.

6. Optional uprated actuators (any pressure) fitted to strengthened welded on aluminium actuator bracket.

7. Compact GT28 bearing housing assembly for optimum water and oil cooling efficiency.

Note. Requires modified oil feed pipe and oil drainpipe. Oil feed adaptor fitting and oil return flange supplied with turbo.

What you can expect for your money

1. Boost pressure starts @ 1,800 - 2,000 R.P.M.

2. Full boost (limited) 2.1 BAR @ 2,800 R.P.M.

3. No drop in power @ 6,700 R.P.M.

4. Increase in torque and horsepower over the TB34 unit through the entire rev range.

5. A conservative 450 BHP potential.

Re-mapping is a must with this unit, as the standard ignition map will not keep up with the fast spool up time of this
unit. Performance will vary depending on engine specification such as camshafts etc.
 
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