987 2.7 vs 986 2.5 review

[southernstar]

986inquiry, thanks for your review. I suspect that the 2.7's you were testing were running poorly, because upon introduction Porsche's notoriously conservative numbers and all contemporary reviews of the 2.7 determined that it was quicker and that the improved torque (and flatter torque curve) meant that it was mcuh more flexible. Indeed, some reviewers felt that the improvements were greater than the numbers suggested.

The gear ratios in the 2.5 had to be higher than ideal as the engine just didn't pull very well at low RPM's. The increased stroke and improved fuel injection addressed those issues.

Brad

[986_inquiry]

Originally Posted by southernstar

986inquiry, thanks for your review. I suspect that the 2.7's you were testing were running poorly, because upon introduction Porsche's notoriously conservative numbers and all contemporary reviews of the 2.7 determined that it was quicker and that the improved torque (and flatter torque curve) meant that it was mcuh more flexible. Indeed, some reviewers felt that the improvements were greater than the numbers suggested.

The gear ratios in the 2.5 had to be higher than ideal as the engine just didn't pull very well at low RPM's. The increased stroke and improved fuel injection addressed those issues.

Brad

i owned a 98 and test drove another 98 and a 99, all felt the same. Test drove several 2000-2004 2.7 and two S, 2001 and 2004, and a 99 911. About a dozen porsches within a few months. All the 2.7 felt slower past 60 mph, and the S's were the only cars that felt similar to the 2.5. 911 was in a different league.

maybe all the 2.7's i drove were bad and maybe all the 2.5's i drove were running strong, but from my experience the 2.5 is faster than a 2.7 past 60. Even the 2006 2.7 I purchased does not feel as fast as the 98 IMHO

[pothole]

Originally Posted by southernstar

The gear ratios in the 2.5 had to be higher than ideal as the engine just didn't pull very well at low RPM's. The increased stroke and improved fuel injection addressed those issues.

Brad

Ratios in the 2.5 higher than ideal? How do you work that out? The 2.5 has nearly 10% lower ratios 1-3. They changed the ratios for the 2.7. So both had ratios to suit the engine, though I'd actually say a 2.7 with the 2.5's ratios would be ideal.

All these cars are great drives and the reality is that there's really not that much in 2.5 through 2.7 and 2.9.

Take 2.5 v 2.7. it's only another 200c and 20-odd hp. Plus the 2.7 has a little more weight to drag around and taller ratios. I'm not saying the 2.7 isn't any faster. But I've driven one and it's not a dramatic difference. How could it be?

I've also compared a 2.5 with a late 2.9, side by side with a rolling start from about 2,00rpm in second through to about 90 or 100mph ish. Think you lot would be surprised at the modest difference in performance. The 2.9 is quicker, but the gap wasn't huge, maybe a car's length by the top of fourth.

[southernstar]

Pothole, you are of course correct re: the transmission gear ratios. When I posted I was thinking of the differential/rear axle gear ratios, where a higher ratio of course means that the engine is revving higher at a given speed. I should also say that I agree that the gear ratios for both the 2.5 and the 2.7 were well-suited to the engines: my reference was to the suggestion that the gear ratios in the 2.5 would be ideal with a 2.7, something with which I disagree. The 2.5, with less torque and a narrower torque band than the 2.7, needed lower transmission ratios and more shifting than the 2.7.

I should also point out that there was virtually no weight increase as between the 1999 2.5 and the 2000 2.7 (about 20 lbs as I recall - although as I have the actual published curb weights for both from Porsche somewhere, I will check and report back if significantly higher). The subsequent base models did increase in weight with the addition of the padded top/cupholders etc. in 2001 and more significantly, the extra top bow, glasss rear window and glove box in 2003.

For the 2000 2.7, as I recall Porsche listed a 0-60 MPH time that was .3 seconds quicker than the 2.5 and the following site shows relative performance in both 0 - 60 and 1/4 mile times.

Porsche 0-60 Times & Porsche Quarter Mile Times | Porsche 911 Carrera 0-60, 944 Turbo, GT2, Boxster S, Cayman R, GT3 and Porsche Cayenne 0 to 60 stats!

This confirms that the 2000 2.7 is .3 seconds faster to 60 MPH and the time differential in the 1/4 mile is nearly 3/4 of a second: 14. 8 seconds for the 1999 2.5 and 14.1 for the 2000 2.7. Not huge, but significant IMO. What is more significant from a driving perspective, however, is the flatter torque curve and its impact on driveability. I'll try to dig up some tests of the 2.7 from back around 2000 by Porsche Excellence magazine, but as I recall the author of one of those tests was the owner of a 2.5. He indicated that, from his hands-on experience in both, the 2.7 seemed closer in performance to the 3.2 than the original 2.5.

The 2.5 is an incredible car, make no mistake about it. However, I believe that it is important that we don't try to get into revisionist history. The changes that Porsche made to the displacement, fuel injection and gear ratios in the 2.7 were done in order to improve both performance and flexibility and, in conjunction with the 3.2 'S' that was introduced in the same year, to answer some of the criticisms of the performance of the 2.5.

Brad

[pothole]

Originally Posted by southernstar

my reference was to the suggestion that the gear ratios in the 2.5 would be ideal with a 2.7, something with which I disagree. The 2.5, with less torque and a narrower torque band than the 2.7, needed lower transmission ratios and more shifting than the 2.7.

I should also point out that there was virtually no weight increase as between the 1999 2.5 and the 2000 2.7 (about 20 lbs as I recall - although as I have the actual published curb weights for both from Porsche somewhere, I will check and report back if significantly higher). The subsequent base models did increase in weight with the addition of the padded top/cupholders etc. in 2001 and more significantly, the extra top bow, glasss rear window and glove box in 2003.

For the 2000 2.7, as I recall Porsche listed a 0-60 MPH time that was .3 seconds quicker than the 2.5 and the following site shows relative performance in both 0 - 60 and 1/4 mile times.

Porsche 0-60 Times & Porsche Quarter Mile Times | Porsche 911 Carrera 0-60, 944 Turbo, GT2, Boxster S, Cayman R, GT3 and Porsche Cayenne 0 to 60 stats!

The 2.5 is an incredible car, make no mistake about it. However, I believe that it is important that we don't try to get into revisionist history. The changes that Porsche made to the displacement, fuel injection and gear ratios in the 2.7 were done in order to improve both performance and flexibility and, in conjunction with the 3.2 'S' that was introduced in the same year, to answer some of the criticisms of the performance of the 2.5.

Brad

Firstly, my point re using the 2.5 gearbox is that I reckon it would allow the advantages of the 2.7 (including higher rev range) to really shine through. One of the reasons for the taller ratios in the 2.7 is better mileage. And I couldn't care less about that. I also don't care whether I lose 5mph at the top. I'm not doing 150mph too often.

Re weight, the book weights only tell half the story. Apparently the early 2.5s are measurably lighter than later 2.5s, and the 2.7s a bit heavier again.

Also bear in mind that Porsche had planned to release more powerful versions of the Boxster earlier, but demand for the 2.5 was massive, so they held out and cashed in. Yes, some mags criticised it for lacking power, but so what?

I've driven pretty much all the 986/987/981 engine options and they're all fantastic. But are the more powerful cars more fun? Not really.

Anyway, the reality is that the performance difference between the 2.5, 2.7 and 2.9 isn't massive. The new 2.7 is a bit of a step up, but even that isn't in a completely different ballpark.

[southernstar]

Pothole we are almost in complete agreement - I have not driven a 981, but all of the 986's and 987's I have driven are a blast to drive. I found the early tiptronics to be a bit sluggish for my tastes, but then again, I vastly prefer a standard transmission in a sports car regardless of performance (and yes, if I were to buy a new 981 it would be a standard, even though it is actually marginally slower)! So yes, marginal performance improvements are only a marginal part of the story.

Yes, there were weight increases over the life of the 2.5's as a result of the addition of side air bags and the strengthening of the rear suspension mounting points. Probably not enough to be really noticeable, but likely in line with the differences in weight between a 1999 2.5 and 2000 2.7. So yes, I am pretty sure that a 1997 2.5 would be little quicker than a 1999 (lets face it, racers will spend a fortune to lose 20 pounds off the weight of a car)!

With respect to the gearing on the 2.7, I do however differ from you. As I recall, the fuel consumption for the 2.7 was only marginally better than the 2.5 ( only on the highway and possibly even worse in the city cycle?). Indeed, upon its introduction I don't recall that Porsche even advertised better fuel mileage (but I have original brochures for both the 1999 2.5 and the 2000 2.7, so I can check and report back if I am mistaken).

To me, the improvements due to the revised gearing on the 2.7 have virtually nothing to do with the increased top speed - as you rightly point out, when do we get a chance to take advantage of that? In conjunction with the improved torque curve, however, it does reduce the amount of shifting that is required to optimize performance in the cut and thrust of daily driving and allows one to attain speeds in excess of 100 kph in second gear. The latter can also be important for those who autocross their vehicles.

Cheers!

Brad

[986_inquiry]

Originally Posted by pothole

Take 2.5 v 2.7. it's only another 200c and 20-odd hp. Plus the 2.7 has a little more weight to drag around and taller ratios. I'm not saying the 2.7 isn't any faster. But I've driven one and it's not a dramatic difference. How could it be?

I've also compared a 2.5 with a late 2.9, side by side with a rolling start from about 2,00rpm in second through to about 90 or 100mph ish. Think you lot would be surprised at the modest difference in performance. The 2.9 is quicker, but the gap wasn't huge, maybe a car's length by the top of fourth.

The 2006 2.7 is 240hp, 20% more HP than the 201 hp in the 2.5. That's quite a jump and should be very noticeable to drivers.

but your experience is similar to what I have experienced, the 2.7 (or 2.9 in your case) is not much different than the 2.5 once you're past second gear.

As I said in my review, if you just want fast and you're comparing a 2.5 and 2.7, they're about the same, either is good

Now how do i get the gearing from my old 2.5 into the 2.7? :dance:

[986_inquiry]

seems I'm right, the 2.5 had the best gearing while the 2.7 has the worse

Originally Posted by insite

actually, they're not. you have to consider the final drive. the 6-speed FD is 3.44. the 2.5L is 3.889 and the 2.7L is 3.555. you need to multiply each geary by this number to get an EFFECTIVE gear ratio.

the truth is, the 2.5L has is geared lower than either of the others by a pretty substantial amount. the 2.7L, IMO, is the LEAST desirable. next is the 6-speed. the 2.5L 5-speed has the most useful ratios from a performance perspective.

[southernstar]

986 inquiry, lower gear ratios are not necessarily better even for 'peformance' driving. I assume we can agree that what is critical is matching the gear ratios to the engine. The 2.5 had less torque, expecially low in the RPM range and hence needed lower gearing. What is more, your analysis fails to take into consideration the fact that the 2.7 and 3.2 had higher redlines - an increase from 6800 rpms to 7200, or roughly 6%. I am quite confident that Porsche, in attempting to improve performance over the 2.5, came up with what they believed were the best ratios to achieve this with the upgraded engines.

Brad

[pothole]

Originally Posted by southernstar

986 inquiry, lower gear ratios are not necessarily better even for 'peformance' driving. I assume we can agree that what is critical is matching the gear ratios to the engine. The 2.5 had less torque, expecially low in the RPM range and hence needed lower gearing. What is more, your analysis fails to take into consideration the fact that the 2.7 and 3.2 had higher redlines - an increase from 6800 rpms to 7200, or roughly 6%. I am quite confident that Porsche, in attempting to improve performance over the 2.5, came up with what they believed were the best ratios to achieve this with the upgraded engines.

Brad

It wasn't just about performance. It was about fuel efficiency, too. Ditto features like stop-start and electric steering in the latest Porsches.

If you don't care about fuel efficiency, the 2.7's ratios will be suboptimal.

Also, you've misunderstood the higher redline of the 2.7. With a higher rev range, you can have shorter gearing. In fact, that was part of my point. With the higher redline of the 2.7, the 2.5's gearing will be seriously sexy. You don't want tall gearing with a high revving engine. You want tall gearing with a torquey, low revving engine.

Geddit?

[southernstar]

Pothole, I thought we were talking about comparisons as between 986 Boxsters, not with respect to the 981. I tend to agree about some features on the new 981(such as electric steering and stop/start technology), as being primarily for the purpose of improved fuel consumption rather than performance. As to fuel efficiency in the 986, I checked the brochures that I have at home for the 1999 2.5 and the 2000 2.7 and 3.2 and nowhere is improved fuel efficiency mentioned, whereas the improved performance is. I agree that high-reving 'peaky' engines should be geared so as to have their engines typically running at higher revs; however, the 2.7 was actually less peaky than the 2.5 - i.e., the torque curve was more flat in the sense that it had a greater percentage of peak torque available down low in the rev range than the 2.5. Of course, this is exactly what you would expect with the increase in stroke in the 2.7 over the 2.5. This is all part of matching the engine to the gear ratios and, while I have no doubt that the gear ratios in the 2.5 are ideal for that engine, I also believe that the same is true for the 2.7 and 3.2 engines.

The higher rev limit does contribute to higher speeds in each gear - increases that are greater than one would expect from gear ratios alone. As I have already said, that is a real boon in the cut and thrust of driving around town as well as for autocross, where one need not shift out of second gear (unless the maximum speed on the course exceeds 65 MPH, which is pretty rare in my experience).

Brad

[986_inquiry]

Originally Posted by southernstar

986 inquiry, lower gear ratios are not necessarily better even for 'peformance' driving. I assume we can agree that what is critical is matching the gear ratios to the engine. The 2.5 had less torque, expecially low in the RPM range and hence needed lower gearing. What is more, your analysis fails to take into consideration the fact that the 2.7 and 3.2 had higher redlines - an increase from 6800 rpms to 7200, or roughly 6%. I am quite confident that Porsche, in attempting to improve performance over the 2.5, came up with what they believed were the best ratios to achieve this with the upgraded engines.

Brad

I can not speak for Porsche since I am not them, all I can say is the 986 feels like the faster vehicle past 2nd gear, which is not good, no one should drive the new Boxster and think "Gee, wish it was as fast as my old Boxster"