2.8T any hard evidence that a DP increases performance? [Archive] - SaabCentral Forums

: 2.8T any hard evidence that a DP increases performance?


Wagon
6th September 2011, 10:07 PM
Any before and after dynos of a DP install everything else being equal?

mike saunders
6th September 2011, 10:17 PM
I;d be curious to see this too. You likely wouldn't see hard number increases, but an actual dyno graph would show the benefit.

All a DP does is decrease the level of backpressure that hinders the turbo's spooling ability. It likely wouldn't produce higher numbers by itself, but you should be able to see the turbo reach its programmed boost output at a slightly lower RPM than stock.

That said...

The 2.8T turbo is pretty small, so the spool benefit from a DP might be negligible.

Wagon
6th September 2011, 10:26 PM
Ya your right. Before and after dynos are a must. I think if I go with a 19T this DP would be benefical. Haven't decided what to do yet.

hrc630
6th September 2011, 10:28 PM
On my Toyota Supra, i have gain 23 whp just with a downpipe.
Also, the downpipe help A LOT in decreasing the temperature under the hood. Before the downpipe, my turbo was glow red, after nothing.
I have had over 20 turbo car and a free downpipe have always give me good result. In the next week, i will make 1 for my Aero.

Wagon
6th September 2011, 10:30 PM
On my Toyota Supra, i have gain 23 whp just with a downpipe.
Also, the downpipe help A LOT in decreasing the temperature under the hood. Before the downpipe, my turbo was glow red, after nothing.
I have had over 20 turbo car and a free downpipe have always give me good result. In the next week, i will make 1 for my Aero.

Are you going to do a before and after dyno?
You know a shop in Quebec that can make this DP? You know of any good exhaust shops near MTL?

hrc630
6th September 2011, 10:38 PM
Are you going to do a before and after dyno?
You know a shop in Quebec that can make this DP? You know of any good exhaust shops near MTL?

I dont know for the dyno. If i have time yes.

For the downpipe, as soon as i have time, i will make it by myself.
I have some 3" stainless piping in the garage and my freinds can make me the flange.

Also, if i dont have time, i have a friends that work in a performance garage an he can make me a full exhaust for under $1000. In the past he have made some crazy exhaust project for me.

Wagon
6th September 2011, 10:59 PM
I dont know for the dyno. If i have time yes.

For the downpipe, as soon as i have time, i will make it by myself.
I have some 3" stainless piping in the garage and my freinds can make me the flange.

Also, if i dont have time, i have a friends that work in a performance garage an he can make me a full exhaust for under $1000. In the past he have made some crazy exhaust project for me.

Do you know any good exhaust shops in or near MTL?

Titansaab27
7th September 2011, 12:58 AM
Do you know any good exhaust shops in or near MTL?

One member on here gained 11hp and like 4 tq all on the top end on his turbo x. Look up "turbo x downpipe thread" the sheets and video should be there

Wagon
7th September 2011, 02:01 AM
One member on here gained 11hp and like 4 tq all on the top end on his turbo x. Look up "turbo x downpipe thread" the sheets and video should be there


If you find the thread please post it up. I will see if I can find it. Did he have a tune or any other mods? Did he lose low or mid?

kanundrum
7th September 2011, 10:33 AM
It was me, will post up info stand by

kanundrum
7th September 2011, 10:36 AM
Stock 2.8l V6 Turbo with K&N Filter


Dynos:


Before

http://i53.tinypic.com/2llenbb.jpg



After

http://i55.tinypic.com/1190xtv.jpg

mike saunders
7th September 2011, 12:32 PM
Those are really solid numbers, especially from a Dyno Dynamics test.

Were both SAE corrected, or uncorrected?

(Trying to see whether a ~5 percent gain was affected by ambient temps....)

kanundrum
7th September 2011, 12:53 PM
yes they were!

Wagon
7th September 2011, 01:50 PM
Did you lose low end tq?

kanundrum
7th September 2011, 02:01 PM
Did you lose low end tq?

Dyno Pics above

Wagon
7th September 2011, 02:20 PM
Dyno Pics above

Yes I see them. It looks like you are losing low end tq (the line is blurry). Is this the case and how much is the loss?

kanundrum
7th September 2011, 02:23 PM
Yes I see them. It looks like you are losing low end tq (the line is blurry). Is this the case and how much is the loss?

There is no loss ?

Look at the lines Red Line is the New Line

Green Line is the old one, compare the figures at 2450 and 2900rpm's

pugsaabaero
7th September 2011, 02:31 PM
there is a gain all across the board which equals fantastic!

Wagon
7th September 2011, 02:32 PM
There is no loss ?

Look at the lines Red Line is the New Line

Green Line is the old one, compare the figures at 2450 and 2900rpm's

Very hard to see on my small screen laptop. So the answer is no there is no lose in low end tq?

kanundrum
7th September 2011, 02:33 PM
Will dyno with Vtune in a few weeks (with all brand new coils and sparks) and Correct no loss

Wagon
7th September 2011, 02:40 PM
Will dyno with Vtune in a few weeks (with all brand new coils and sparks) and Correct no loss

Sweet!!! Thanks for your effort!

BadBrains
7th September 2011, 06:43 PM
Do you know any good exhaust shops in or near MTL?

http://rawtekinc.com/

mike saunders
7th September 2011, 07:00 PM
Very hard to see on my small screen laptop. So the answer is no there is no lose in low end tq?

No loss, but no huge gain either.

Torque delivery with DP looks to be about 100-150 rpm ahead of stock, which makes sense. The raw numbers are essentially the same, which also makes sense.

The DP seems like it improved high-end breathing, and yielded about 5 percent gain, nearly all of it above 4,700 RPM. That's not a huge numeric gain, but drivability is probably improved by the low-end torque improvement. The car probably feels "peppier" at sub-highway speeds.

The biggest benefit of the DP is probably going to be seen with programming....

9-3gotboostAERO
7th September 2011, 07:53 PM
Underhood temps will severely drop and this downpipe will see huge gains after a compressor swap and tune

kanundrum
7th September 2011, 09:03 PM
With it Vtuned it really is amazing if I wasn't having so many coil issues I'd get the dyno sooner. But this weekend I will be swapping everything out and getting a dyno in up coming weeks.

Wagon
8th September 2011, 12:06 AM
With it Vtuned it really is amazing if I wasn't having so many coil issues I'd get the dyno sooner. But this weekend I will be swapping everything out and getting a dyno in up coming weeks.

What diameter is the dp? Is the rest of the exhaust stock?

kanundrum
8th September 2011, 07:03 AM
All is 3" until the stock mufflers.

Muffler area is still normal stock size (Kept that way for TurboX Sound)

I Have 1 Race cat (vibrant)

mike saunders
8th September 2011, 08:54 AM
Underhood temps will severely drop and this downpipe will see huge gains after a compressor swap and tune

If underhood temps are dropping as much as folks claim, then that's a likely sign that the stock setup (turbine wheel, exhaust housing, DP) is severely undersized.

para pat
9th September 2011, 02:03 AM
That would be due to the elimination of the underhood cat.

jim808
9th September 2011, 04:47 PM
Anybody see any gains from just from just cutting out the second cat and using a straight pipe? Maptun likes to promote their downpipe (midpipe) as greatly reducing back pressure. Any truth to this? Its a pretty easy mod especially if it yeilds some addtional HP.

pugsaabaero
9th September 2011, 05:32 PM
getting my mid pipe chopped next weekend and on the dyno end of this month i can have raw numbers then. I found someone localy for my downpipe but i have a question people are spacing out the o2 sensor on the cat on the DP so it's only catching a sniff and not causing a CEL. Anyone have info on that spacing or photo? Trying to bring specs to this guy because he is a hobbyist and is down for working on it just never fabbed one on the lp9.

2.8t
9th September 2011, 10:12 PM
I've got 3" turbo back exhaust and I can definitely tell the car gained a few ponies. And especially when heat wrapped it did decrease temps in the engine bay.. but if you're looking to decrease engine bay temps you could always ceramic coat the intake mani, heat wrap the downpipe if you have an after market one, and remove the plumbing from the front end and get rid of all of those engine covers. I did all that with mine and a fmic, aside from the ceramic coating and my radiator support which used to be extremely hot after running the engine hard is ice cold now pretty surprising but with increased ventilation it really helps.

kanundrum
13th September 2011, 09:35 AM
Looks like you XWD folks have a DP

at least the 2nd part.


http://www.genuinesaab.com/catalog/product_info.php?products_id=843