Uprated oil cooler or water rad?

griffindai

Torque Junkie
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Location
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Saab 9-3 v6 Aero
With some knowledgable petrol heads on here...probably the best place to ask ;)

Next year's project is tackle the cooling side on the SAAB as it gets a bit warm in there now on the new tune. I'll be pushing the IC right up front for better airflow as its sandwiched between the rad & AC at the moment so not ideal (might have to fit a thinner but taller/wider IC though so drop down to 50mm instead of this 90mm evo one)

Main reason for the IC swap is to fit a larger water rad but might get away with keeping the 90mm one, Courtney Sport sell a 50mm uprated alloy rad for the Vectra VXR which should drop straight in, meant to really aid with the cooling system as its plumbed in differently and seems a must on the Vec's especially running the bigger 18t turbo.

Also looking at an uprated oil cooler, basically uses a billet adapter plate then you mount the new cooler in front of the IC. I'm off the the states in Feb so could bring this back in the case plus the oil cooler and get the rest of the bits from the UK.

The Courtney water rads around £700 and I'm guessing labour will be around £150ish, a new IC (probably the DO88 drop in kit) is around £350.

The oil cooler upgrade including the adapter plate, 19 row cooler plus hoses/fitting parts will probably come to say £5/600 plus labour and again guessing around £150 to get it all plumbed in.

What would be the most beneficial to upgrade first? Can't afford to do both in one go so there'll be a few months gap between each upgrade.

Also looking at either swapping the 3" DP out for a 5" and have that ceramic coated (heat shield won't be able to be refitted here!) or just have this 3" one sent off to be ceramic coated (not 100% on the 5" DP yet, meant to reduce spool up time by a bit and give more top end) but that's towards the end of next year!

Anyway! What do you recon? Upgrade Water rad or oil cooler?

Thanks Dai
 
When you say gets a bit warm, what do you actually mean by this? Water temp, oil temp or both, up to what temps and under what conditions?

5" downpipe seems very big. Would you increase the rest of the system to match?
 
a repeat of ogs post really
But remeber mods are no use just for the sake of them . Fine if they improve something but if what you upgrade is fine already then there will be little benefit.
As a straight choice if the oil temp is higher than it should be I would do the oil cooler first.
As to the exhaust - changing one part usually doesnt help much , unless it is the weak link - on a turbo engine what you want is to get rid of the gases asap.
Putting a monster downpipe on usually is a wate of time if it is loads bigger than the system
As for improving spool up time easiest that is unlikely to improve for the same reason.
 
When you say gets a bit warm, what do you actually mean by this? Water temp, oil temp or both, up to what temps and under what conditions?

5" downpipe seems very big. Would you increase the rest of the system to match?

Water temp mainly mate, I'll dig out the info later but the new water rad re-routes the pipework and sounds much more efficient. When I'm home next I'll get HP Tuners on there and log the oil & water temps.

The oil cooler sounds a must on bigger turbo'd 2.8 v6t's (gt30/holset etc) and beneficial for those running the 20T. Mines only mildly tuned really (compared to what's in the states & Sweden!!) but figured May aswel upgrade this is the rest is getting done.

5"DP- jury's still out on that tbh, I'll get the info later but it's meant to reduce spool up & improve top end power, that's a maybe for later next year though, main job to sort first is the cooling.
 
a repeat of ogs post really
But remeber mods are no use just for the sake of them . Fine if they improve something but if what you upgrade is fine already then there will be little benefit.
As a straight choice if the oil temp is higher than it should be I would do the oil cooler first.
As to the exhaust - changing one part usually doesnt help much , unless it is the weak link - on a turbo engine what you want is to get rid of the gases asap.
Putting a monster downpipe on usually is a wate of time if it is loads bigger than the system
As for improving spool up time easiest that is unlikely to improve for the same reason.

Thabks mate, I'm on the fence with the 5" DP. Still trying to get better info on that one and if anyone's tested it on the TD04. I think it was tried out with a HX35.

I'll have to log the coolant & oil temps when I'm home to see exactly what happening.

Performance side I'm 99% happy with now, just want to tackle the cooling side :)
 
A 5 inch down pipe seems to be an overkill.
FWIW my 3 inch DP supports app 450 FW HP OR 390 HP at the tyres.
 
Here's the info on the 5" DP:

The second option is our special 5 inch expansion chamber downpipe. This downpipe has a large 5 inch exhaust section behinsd the turbine outlet. Turbine wheel efficency is rated in work extracted from exhaust, and efficecny can be increased by changing the pressure across the wheel. More pressure on the wheel inlet, and less on the wheel outlet increases efficency. The large chamber creates a low pressure zone directly behind the turbine wheel, similar to running no downpipe. The effect is reduced spool time and increases top end efficency. Once the exhaust gas as expanded out in to the chamber and cooled, it is tapered back down in to a 3 inch tube, so that exhaust velocity is retained. The only downsite to this downpipe is that the factory heat shield cannot be retained, as well as a catalytic converter cannot be added to it.

https://sites.google.com/site/cbmotorworks/saab/9-3-ng/saab/2-8t-downpipes
 
My (limited) understanding of gas flow is that increasing the diameter of a pipe reduces gas velocity which increases pressure.
 
Here's a screen shot of the info for the uprated water rad:

08CCD246-BFE3-41E4-B30C-CBF40DCE07DF_zpswqaboyul.png


The guys who sell the 5"DP also sell an uprated rad in the link above for around £450(ish) but then have to factor in shipping costs plus tax and any issues that may arise with fitting or if it gets damaged in transit from the states (always a pain to sort out!!!) Probably beter off just spending the extra and going to Courtney here.
 
My (limited) understanding of gas flow is that increasing the diameter of a pipe reduces gas velocity which increases pressure.

IMO logic tells me that zero back pressure post turbo should not increase pre turbine pressures as they are governed by the manifold design and the turbine AR ratio as well as the RPM's and load on the motor.

The large 5 inch turbo dump pipe will minimize post turbo back pressure.

Am sure that there will be a guru or three that will enlighten us all on the subject
 
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I dont think a short 5 " section is anything like no downpipe. With the latter the gases are in the atmosphere virtually immeadiately so there is no pressure to build up ever as the gases have "gone."

If you have a short 5" section as soon as that area fills with gas it will build up pressure again and any benefit that you might theoretically of had will be gone. The pressure will not be decreased unless the exhaust can flow all the exhaust gases , and if that is happening you dont need the larger area in the first place.
It is the same the other way round a 4 " system isnt much good with a small downpipe and a 2" cat.
 

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