Loss of Power over 4500 rpm

[Grafyte]

Hi everyone. I'm looking for thoughts and opinions.

I have a 2000 Volvo V70 that I purchased 2 years ago. It is the 168hp non turbo version. As stated in the subject line, I'm experiencing what I believe is a loss of power above 4500 rpm.

Let me start with some facts about the vehicle. It's non turbo. It's automatic. It has no check engine lights and no codes. It runs smoothly. It gets excellent fuel economy (32mpg highway in summer). It's up to date on all maintenance. It doesn't really have any tangible or visible issues. However, I bought this vehicle as a replacement for a 2020 Toyota Tacoma that had a 159hp 2.7L engine. My V70, which on paper weighs 700 lbs less, has less drag area, and makes 10 more horsepower, is slower than that Tacoma, under as near identical conditions as I can get.
( is a video demonstration on the exact same road)

I made another video recording my rpm, engine load, manifold pressure, and fuel flow, and what I discovered is that around 4700 rpm or so, despite the fact that the manifold pressure remains fairly constant, my engine load goes down and my fuel flow basically plateau even as the rpm climbs. I'm not trying to promote my videos at all, and I don't care if you watch, them, but I provide links so that my words can be more trustworthy. In this video, I start at around 7200 ft elevation, full throttle (with kickdown switch depressed) into 3rd gear, and climb a hill which at the crest is 7350 ft elevation, and I lift at the crest. At 7200-7350 ft elevation, I'm expecting around 11.3 psi of ambient air pressure and that's what my tool measured in the manifold, at least to start. Here is that video:



Now I want you all to have some more info. Here are 2 videos of similar cars (especially from the B pillar forward), one being my V70, and the other being an S70, which I sold in 2019. They are both full throttle pulls taken on the exact same road at 323 feet elevation. Despite living in Colorado, I road trip this car fairly often, because it's just so good at absorbing miles. Needless to say I'm keenly aware how abnormal this car's performance seems.

S70 acceleration:
V70 acceleration:

I notice how the V70 tends to "hang up" at the higher rpm, then it lurches when it shifts because the rpm drops and the power comes back. The S70 is smooth all the way through. For these 2 videos, the S70 was running 89 octane fuel, and the V70 was running 87 octane. Not sure how much difference that makes. When I measure my ignition timing on my V70, I notice no change under 40% engine load between 87 and 91 octane, and about 4-6 degrees lower on 87 octane above 60% load. From the driver seat I notice no changes in performance on 91 octane vs 87.

I have taken the car to 3 (three) different facilities and they have all told me the car is healthy as far as they can tell and that there is no exhaust restriction, which was my initial suspicion, but with 3 professional opinions disproving that hypothesis, I can no longer hang on to that idea. For another reference, There exists a car, the Honda Civic CX, which in 1993 made 70hp. My car breaks even on that car provided the civic is shifted slowly and unskillfully. More video evidence: .
So that is the kind of performance I put up with in my V70. 16-17 seconds 0-60, 13 seconds down steep hills, and up hill is ... this: .
I know these wagons are slow, especially the non turbos, but I'm working with advanced slowness.

So what are your thoughts?

[yanga001]

Check tranny fluid and see if it’s low, or burned. My 98 had periodic acceleration issues which turned out to be low fluid. I also had odd ball bad motor mounts which caused the transmission to pop into neutral due to flexing. Was resolved with proper tranny fluid changes and new mounts.

In your case I’d check the tranny fluid. To see if there is indeed a problem. A fluid refresh may just be helpful if it wasn’t done.

These cars are pretty slow to start, they were fast by 90’s standards but extremely slow by today’s standard. A big standard 2009 Hyundai with the 4 cylinder engine is stated to be faster than our na wagons.

[matthew1]

Welcome to MVS, Grafyte. I have some thoughts. Sample differences do occur within models, straight from the factory. We've all read about someone's stock [whatever] being noticeably fast for what it is, even measured against his friend's [same car]. Same variance probably exists in the edge cases of slow cars.

NA engines suffer even at Denver altitude, which is a couple thousand feet below where you were. I've been a member of a couple FB Colorado car groups for years, and newcomers complain their NA cars have no power here. EVs had a huge advantage at Bandimere (drag strip) even against modified turbo cars.

Other thoughts are compare what you've done to it vs. the Stage 0 list https://www.matthewsvolvosite.com/stage-0/, and good fuel economy is a positive sign regarding the Stage 0 list being complete or close to it.