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Discussion Starter · #1 ·

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sigh i wish i had 550 dollars lying around :cry:
 

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Looks nice but the extra volume and surface area mean heat energy is lost and thus there is less power to drive the turbo. Probably worth it if you are trying to squeeze some more high rpm power out of a non stock big turbo but for stock setups I'm not sure it's worth it.
 

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Discussion Starter · #4 ·
Shirozina said:
Looks nice but the extra volume and surface area mean heat energy is lost and thus there is less power to drive the turbo. Probably worth it if you are trying to squeeze some more high rpm power out of a non stock big turbo but for stock setups I'm not sure it's worth it.

Uhh, ok.


Anyway, if these do as much as my set on my C900, it's worth it.

It made the upper RPM's come alive.

The turbo supply on the stock header is laughable, if you have ever seen one off the car.

The ports are about as big as quarters.


Plus, if you look at the stock one, it's 2 "T's" where all the gasses and pulses bang off eachother.

*cue vigge to say that the stock one is good for up to 400 hp*

:)
 

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Yes, there is more surface area to let off heat... wich is why you wrap it in thermo-techs copper infused heat wrap.

God I wish I had 550 laying around.

One question though, I only have a stock tdo4, will I still benefit from the better flow (I know I will but I guess what Im asking is whether or not it will be significant).
 

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Discussion Starter · #7 ·
I would like to point out that when you wrap 95% of the aftermarket headers on the market today, you void the warranty.


These will be no different.


Also, as far as the heat loss, I would not worry about it. I really don't think it will be an issue.


As for needing it with the stock turbo...


I put one on my C900 with a stock turbo and it made a great difference above 3800 rpms. You cannot compare the two really, but that's my experince.
 

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Heat loss is a massive issue - it's heat that drives the turbo and the surface area of these headers is way bigger than stock and unlike the c900 it's directly in the airstream from the front of the car and will be cooled very effectivley - these things will be a huge heat exchanger which is absolutley not what you want on a turbo car in this vital area. Even if you wrap it and solve this issue (and get round the heat damage on these thin walled pipes) the internal diameter is bigger and that means slower gas velocity - the stock header diameter is not sized small for an arbitary reason. Increased volume means slower spoolup and on at least 2 of the header lengths the path is more indirect and 'twisty' than stock. The c900 has an inefficient header I'll agree because of the off center turbo mount but the central position of the NG900/9-3 is much more efficient with much smaller overal header length differences. Timed or tuned exhuast pulses are used to squeeze the last drop of high RPM power out of big turbo's or to up the power at a specific rpm band but for a stock application they will loose you power and drivability in other areas additionaly it's not just the equal length - the actual length and diameter have to be precisley calculated in order to maximise the 'tune' and I would have thought this also has to be done in conjunction with a specific turbo.
 

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I would put it this way, do not look into the engine as part by part manner and make calls what is usefull and not. Insteand look at the engine as a whole from filter to tailpipe, make plans on what is wanted and then work to achieve your goal. By this I mean that far too often the dicussion is taken to single parts and gains obtained with them in a completely different set-ups are laid out as "proof" that the same gain is open for grabs being the HW of the car what so ever.

But lets take an exemple GT3071 and HW around it. My route was tube header from the beginning to avoid the mounting problems which one will face with the orig manifold and also to get rid of cobra, or something that resembles it. Rest of the engine was left untouched thus T5 cams. This got me into the bhp class of 400+ (412 dynoed), but then came the dead end futher bhp could not be really released with further mapping. Tried different timing maps, boost, afr but nothing so leave the dyno and think of some furhter mods. Then came cams and ported head and bhp jumped up by almost 100bhp (507bhp/445whp). Besides my car there are quit many others which are in the category of 400-430 with orig head/cams and 450-510bhp with upgraded cams/head, so one could state that with that turbo thats where you will most likely land, assuming of course that HW has no issues and mapping is in order. Both std and tube manifolds are utilized and at lest in the lower category it does not seem to make much difference which one you run.

Here is an exmaple though with doing it the other way around as what I did, ie. 9000 stage 6 with orig manifold and a DP from rear Made the usual 400+, thus cams upgraded. However in this installation they had utilized the normal after market 9000 dp, ie the one which has the first 180deg bend from 2.5" piping + and elbow to connect it to the turbine. Both of the parts (DP bend and elbow) are know to become bottleks sooner or later.
Then came the tube header + a new DP and before and after did look like this


So the new equal lenght pulsating header did not improve/lower the spool, as what the usual expectation says, endeed a loss of 70Nm was noted at 3500rpms. According to the texts in the orignal topic where these plots where posted it was stated that for the tube run the boost was higher 4000-5000rpm. So lets put that aside and we can note that after both are spooled there isnt much change until rpms >5000. In this are we see alot of gain, but as stated earlier how much comes from the tube and how much from DP/elbow upgrade.

So summarize it, see out that all that you're not running with any known bottle necs which will limit power and buy/purchase parts to fit to your own bhp/registry goal and not somebody elses.
 

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A loss in TQ, and gain in HP means you have freed up a high RPM bottle-neck.
I'm willing to be EGT decreased, and Airflow increased in higher RPM


..just a guess.?


although, you changed a handful of parts at once, so it would be VERY tough to single one improvement over another.
 

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Is the stock exhaust header a bottleneck/restriction though - is so yes replace but if it aint broke why fix it?
 

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I'm guessing you've never seen one off the car.
it's about the crappiest design I've ever seen.
Well... it's GREAT for saab's intended purpose; low RPM grunt to feel like a v6.
It's not ideal for ANY type of high RPM anything. This is why "you guys" are stuck complaining and worrying about high EGT's in modified cars.
 

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I've see plenty of Saab headers off the car and high RPM power would be a great thing if Saab engines were high reving in the first place. I'm not saying these things are no good - but they should be sold with the proviso that you are going to use them with an upgraded turbo - don't expect to stick on on your T25 and suddenly see large power gains.
 

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Shirozina said:
I've see plenty of Saab headers off the car and high RPM power would be a great thing if Saab engines were high reving in the first place. I'm not saying these things are no good - but they should be sold with the proviso that you are going to use them with an upgraded turbo - don't expect to stick on on your T25 and suddenly see large power gains.
And what would you say about sticking one on a tdo4?
 

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I've no doubt that you will see some gains at the top of the rev range but will probably loose low down power and have more lag - if you have the choice I would put the money on an ECU upgrade - way more bang for your money. Again I'm not saying these things won't do anything but on a stock setup or even with a few stages of tune there are likely more ways of getting more power for this level of spend.
 

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G96nt said:
I'm guessing you've never seen one off the car.
it's about the crappiest design I've ever seen.
Well... it's GREAT for saab's intended purpose; low RPM grunt to feel like a v6.
It's not ideal for ANY type of high RPM anything. This is why "you guys" are stuck complaining and worrying about high EGT's in modified cars.
You call it crap based on looks or you do have something else to support that point of view?

But lets strip down the EGT problem which in many cases has nothing to do with the header.
Firstly the std turbo is desined for low end grunt with operation range of roughly 2000-4500rpm after which you will clog the turbine more or less regarless of the header. Once tuned people try to "wind" figures out of which really arent possible often with the though more boost brings more power, thus the only thing it does it raises the post compressor temp, turbine pressure and EGT.
Combine this with a high compression engine which to begin with runs on very low ignition timing (you lucky in some engine if you even see 10deg in high end). The mapping style "more boost is good" naturally makes it even harder to run decent timing and often on the road you do see that the ECU further pulls back from the already ananomous timing further raising the EGT's

If all this sounds strange, I doubt you to install a tube header to your car and then try to "over map it" with std turbo without high EGT's.

For the record I know plenty of cars with adequate turbo in orig manifold running 400++ without any EGT problems nor overfueling.

IMHO you have two restrictions what you will face at 400++ level, one being the cams and the other being the header and if the turbo is not huge (3071 at highest) the cams will start to limit before the header, but in the end you need to swap them both.
 

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Im saving up for the stg. 4 software so I will absolutley make that my next big mod, but I was just interested in knowing for my future endevors. Thanks though.
 

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Discussion Starter · #20 ·
More pictures of the 9000 one:



 
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