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Discussion Starter #1
I have heard of people doing this and gaining huge in the mid range, with a corresponding slight loss in the high end. Anybody tryed it. What particular RPM's is it the most benificial? When does the power fall off compared to the shorter turbo manifold? This seems like a cheap and significant gain, so it made me very curious. Thanks guys.
 

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I have tried this on one of my 2.0 cars. It works very well. The big problem is that it will change the VE enough to make a big mess of the tuning. I was able to retune it quickly on the dyno in steady state to re optimize the timing and fuel. So basically it works great but would take a custom tune.

Blue is with the 2.0 Intake Red same hardware except with 2.3 intake manifold.


Boost pressure is the same here. Fuel pressure is a problem but dealt with elsewhere.


Some comparison images. Intake Gallery
Rough hardware list:
GT3071 .64, T5 T exh cam, 2.3I inlet cam, green injectors, pistons, Log exh manifold with top mount turbo, big intercooler.
 

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Discussion Starter #4
So it would not be suggested on a car without a tune at all I would assume. My mods thus far are Nick's version two downpipe, Spatl's MBC+a, local exhaust shops 2.5 catback with a cherrybomb(it is way too loud and I want a bigger muffler) CAI, exhaust rap on the header and downpipe, and a Viggen intercooler. Would I be changing too many things for the stock ECU to cope with when adding the different intake? I think I probally already have since my plugs foul so quickly, I think the car runs rich. The plugs get all sooty.
 

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wait...
how is that bad?

It looks like the a/f overlap entirely, but the power-curve if just pushed further out.
 

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Discussion Starter #7
??????????????that's what I want to know?????????????????????
 

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G96nt said:
wait...
how is that bad?

It looks like the a/f overlap entirely, but the power-curve if just pushed further out.
isnt it just the other way around, the 2.3 intake moves the power band lower in the rpm range?

Nick what did the MAT read during these runs?

personally I fawor it the other way around, i.e avoid bhp drop in higher rpm's, it suit my goals better, i.e GO in strait line up the gears.
 

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Vigge said:
isnt it just the other way around, the 2.3 intake moves the power band lower in the rpm range?

Nick what did the MAT read during these runs?

personally I fawor it the other way around, i.e avoid bhp drop in higher rpm's, it suit my goals better, i.e GO in strait line up the gears.
sorry; comes on sooner, but falls off faster.

What was being over-run? to have the power drop off so steeply after 6k.. eep.
 

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Air temps were similar on the two runs, within 10f of ambient. I was logging those in Nira.

The displayed data is after optimizing the tuning for the hardware. The first driving after changing was not safe for a full throttle run.

If anything is killing high rpm power it is the stock cylinder head / springs with 120K on them and or the camshaft combination / timing. Not to mention the tiny .64 exh housing. Or the log manifold. I will hopefully test back to back with different manifold soon. I will get the new fuel pump, larger 1000cc injectors and valve springs. E85 too.

My plan is to make enough high rpm torque to do decent Hp but be nice to the gearbox while having a decent midrange power so the daily driving is nice. I don't want to have to use 3rd gear on the highway hills.
 

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NickTaliaferro said:
Air temps were similar on the two runs, within 10f of ambient. I was logging those in Nira.

The displayed data is after optimizing the tuning for the hardware. The first driving after changing was not safe for a full throttle run.

If anything is killing high rpm power it is the stock cylinder head / springs with 120K on them and or the camshaft combination / timing. Not to mention the tiny .64 exh housing. Or the log manifold. I will hopefully test back to back with different manifold soon. I will get the new fuel pump, larger 1000cc injectors and valve springs. E85 too.

My plan is to make enough high rpm torque to do decent Hp but be nice to the gearbox while having a decent midrange power so the daily driving is nice. I don't want to have to use 3rd gear on the highway hills.
Nick, how long time wise is the sweep in usually run in the dyno? The reason for asking is that if I look at the boost build up curve in the above runs are much worse than what I have seen in two of my friends B204's with GT3071 ar. 0.86 housing. They look like this on the road with 3rd gear (4.05 final drive box)
www.stcf.net/viggen/B204.pdf

Yes I know boost is not the primary target to monitor, but the full acceleration correletes directly with boost in the example case, i.e max torque is reached at those rpms also. Cams T5 in and out.
 

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We try to keep the run time comparable to real world so on this is was 10-12s for the runs. It is pretty easy to adjust the eddy current to get enough load. It looks similar except in your example it is starting from 3000rpm. We start from 0 load, 2K so getting a "run at it" might make a bit of a difference. This is comparing apples to oranges anyway.. I was comparing lemons to lemons.. I think some of the boost response is in the control mode. It could also be from the less than ideal exh manifold. I would have to go look at the later dyno runs from that car to be sure.
 

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NickTaliaferro said:
We try to keep the run time comparable to real world so on this is was 10-12s for the runs. It is pretty easy to adjust the eddy current to get enough load. It looks similar except in your example it is starting from 3000rpm. We start from 0 load, 2K so getting a "run at it" might make a bit of a difference. This is comparing apples to oranges anyway.. I was comparing lemons to lemons.. I think some of the boost response is in the control mode. It could also be from the less than ideal exh manifold. I would have to go look at the later dyno runs from that car to be sure.
What exhaust manifold is being run on this setup? Standard unit or a custom tube manifold?
 

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NickTaliaferro said:
We try to keep the run time comparable to real world so on this is was 10-12s for the runs. .
I personally prefer a dyno run which resembles 3rd gear on the road, because that is the gear I do/start most of my WOT runs, so roughly the same as to what you have used in those runs.
 

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When testing we do many different loadings and varying the fans to get the charge temp up to simulate traffic etc. For testing we make sure everything including coolant, oil temp acceleration rate is the same, to eliminate as many variables as possible.


The manifold is a Log for now on the 2.0 nira car. I plan to swap this with a individual runner style to see how it differs.

I am now running a tubular near equal length on my viggen. This but all finished:
 

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I would have to go measure one for sure but almost certain the throttle would run into the brake master. But on your "backwards" cars it just might work. :) The upper corners might run into the strut brace.
 

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NickTaliaferro said:
I would have to go measure one for sure but almost certain the throttle would run into the brake master. But on your "backwards" cars it just might work. :) The upper corners might run into the strut brace.
Agreed! It might produce some intresting results. I am surprised there isn't an aftermarket intake manifold... ;)
 

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Discussion Starter #20
Ok guys this is all very interesting, and I understand that it would not be ideal without a custom tune, but can I run it with my current mods or am I going to make things worse off? Like I said befor this seems like a cheap power mod and is very exciting for me. Would I see a real benifit from it?
 
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