How fast is a 850 Turbo?

[csbrianp]

I was concerned about back pressure when I put a magnaflow muffler on my 850 T ( which I'm loving more and more as it breaks in ! ) the car seams to run faster although I haven't time it.

Then I met this Volvo head through the purchase of his 760 wagon that has a 940 transplant motor and 5-speed tranny. It has 3" exhaust and a Dynomax muffler which he claims dynoed @ 215lbs of torque ( 20 lbs over stock ) and an additional 5hp.

What I CAN verify is that the Konis and diesel springs ( cut 1 coil to take down to stock height ) he put on this car allows it to OUTHANDLE my 850 T.

If I had the money, I would put 3" exhaust on the 850. It certainly will help it run cooler if nothing else which is always beneficial w/ a turbocharger.

va007

What you wrote here about the 760 wagon out handling your 850 Turbo, is true. My wife drives an 98 S90. Nice car, and boy does it handle. Big sway bars produce little lean, and even though my 850s are lowered one does not feel the confidence taking a very high speed corner as you do in the 960/S90. Now, if it only had the twin turbo motor out of the S80.

Brian

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[csbrianp]

What is really crazy is my car now gets great gas mileage. Before the tires I averaged 22 mpg around town and 25 on the highway. Now my highway averages 28.5, and around town never below 25. A friend told me my numbers improved because the wheels are turning faster and showing more miles driven. I agree, and that might be worth 1 maybe 1.5, but not 3 mpg more. Right now with 65 miles on this tank I'm averaging 31.8, and of course it's mostly freeway.

Brian

One tire size difference can throw your speedo off 10% which would account for the apparent difference in gas mileage.

I need to edit that last statement which is incorrect. I tire size difference on the first # ( example: 205 )will throw off your speedo about 1.6%. 1 size on the second # will throw it off 3%. Sorry about that...

Here's a site where you just put in the different tire sizes and it shows you the speedo difference. MIJ had found this :

http://www.miata.net/garage/tirecalc.html

In theory a larger tire should give better gas mileage ( fewer engine revs ) but only if the driver compensates for the extra torque required to turn the larger tires by accelerating easier.

I verify my speedo at those radar speed checkers on trailers.

va007

We are not taking one thing into consideration, and that's the amount of torque the engine produces at any given rpm. To better your fuel mileage lower rpms always seemed the way to go if you were driving a car with a lot of torque in the lower rpm range. After installing shorter tires my 850 turbo is turning 3300 rpms @80 mph meaning there is more hp available which uses less gas to because it doesn't have to get to the power band to maintain speed. I drove from Phoenix to Blythe 209 miles and averaged 33 mpg. Of course I was using the cars computer to figure the mileage but that's 7 mpg better than my 850R gets with larger wheels, and 6 mpg better than it got before I changed from the 205/50, to the 205/45 tires. I can see some gains using your above calculations but not this much.

Brian

[raint5]

so everything i have read in this post has been fairly educating, except that everytime i consider a, it seems like everyone on the forum cautions me about bending rods, so im a little sketched out about mbc and 3" exhaust and all that, can someone please tell me how to get hp without detontation?

[polskamafia mjl]

If you have a T5 then you shouldn;t be worried about bending anything...unless you do something ridiculous. The T5's are very robust turbo engines and can handle a lot of power.

[raint5]

so its the glt that tends to bend rods? not the b5234t?

[hausmeister]

Gonna revive this...

So, I already fixed many issues on my T5-R auto wagon, and vom 0-60 (100kmh) it takes 8 seconds. I'm not unhappy, It feels fast (takes about 3sec to 40(60mkh)), but I guess there is still about 1sec lost somewhere.

So, this what I did already and what brought the car vom 12sec to 8:

replaced complete ignition
replaced the obvious vacuum lines to the turbo and everything else that is easily reachable. (so not all of them)
IPD TCV
New fuel filter, fuel pressure regulator, refurbished Injectors.
Fluids replaced (auto flush)
K&N filter
used MAF (cel was on)
Cleaned intake tubing
Put in a boost gauge, turbo pressure seems ok: ~0.7bar, ~0.9bar near redline.(that's like 10 to 13 psi)
(other stuff thats not related to engine)

any idea where I might find that missing second?
Before I think about tuning I want to get it to run right. After that maybe exhaust+new software. It runs much better than when I started, but the idle is still somewhat rough and it takes a couple of turns to start the engine.
I guess it is normal, but I don't get full boost in first gear, ony in 2nd or 3rd and then I am already going faster than 60 mph - so from 0-60 I actually don't get the "R" overboost...

[matthew1]

Before I think about tuning I want to get it to run right. After that maybe exhaust+new software.

You're thinking and doing right.

It runs much better than when I started, but the idle is still somewhat rough and it takes a couple of turns to start the engine.

Codes?

I guess it is normal, but I don't get full boost in first gear, ony in 2nd or 3rd and then I am already going faster than 60 mph - so from 0-60 I actually don't get the "R" overboost...

Yep, normal.

any idea where I might find that missing second?

There are so many variables at play... well you're starting at the right spot: Stage 0. I'm going to guess there's something killing a few hp and it's related to the rough idle.

[hausmeister]

No codes since I fixed the vaccum lines and the MAF

I'm going to guess there's something killing a few hp and it's related to the rough idle.

That is also what I am thinking... What should I be looking for? still a vaccum leak somewhere maybe? Today I bypassed the brake booster line because the end connected to the manifold looked like someone chewed it off... so it's possible I'm still missing something here, this was definitely not airtight.
Boost and vacuum was looking fine so I thought I was golden, but maybe not.

Previous owner said he replaced the pcv - not sure I f he did it right. could there be something messed up?

A tip for peolpe doing a stage 0: The refurbished injectors made a huge difference for me.

[matthew1]

Spark plugs - brand/model? Did you check the gap? Should be .028".

[hausmeister]

Plugs are new Volvo OEM... didn't check the gaps. Like I said, complete ignition is new. There was a wrong coil installed, worn out distributor and the wires were full of oil.

I think it is in the higher rpm range where some power is missing. When the transmission shifts up I get a small 'boost'...