Why does the stock 2017/2018 Si seem to underperform on the 0-60 & quarter mile relative to specs?

[kritz]

First thing that came into mind.
Previously the SI was N/A the power was always there even after each shift.
With the new turbo engine, if you release the gas pedal for shifting the car losses boost pressure and momentum. It has to build boost again on the next shift. I know isn't a lot of time but it hurts anyway.

With all the fuss of the whp numbers I was expecting people making mid 14's in average stock but that isn't the case. The car is performing (acceleration wise) like the old ones.

The new Accord 2.0T manual has the same issue. The acceleration numbers are almost identical to the SI. I'm sure that's the reason these cars respond so well to flashes.
Accord/Civic
0-60 6.1 vs 6.3
1/4 mile 14.7 at 98 vs 14.8 at 96
C&D tests.

Noel, does your Mitsubishi do this as well(lose boost on shifts)??

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[NoelPR]

The new Accord 2.0T manual has the same issue. The acceleration numbers are almost identical to the SI. I'm sure that's the reason these cars respond so well to flashes.
Accord/Civic
0-60 6.1 vs 6.3
1/4 mile 14.7 at 98 vs 14.8 at 96
C&D tests.

Noel, does your Mitsubishi do this as well(lose boost on shifts)??

No.
Is automatic (dual clutch) gas pedal is pressed all the time under hard acceleration, so boost is on the max allowed by the Wastegate Actuator.

With a basemap reflash and a boostpill to trick the ecu to command more boost, I clocked high 4s 0-60mph (video here). Cool for less than $300.

 

[samaximuss]

According to this post: http://blog.vittuned.com/introducing-the-2017-civic-si/ and other dynos I've seen it seems that Honda slightly undersold the torque and horsepower specs on the 10th Gen SI. We're talking ~220 ft-lb of torque observed at the wheels and 205 HP at the wheels, which is better or equal than what Honda is advertising at the crankshaft.

Based on those numbers and the weight of the car I would expect to see a little bit better than the reported 0-60 times of 6.5 - 7.0 seconds and the ~ 15 second quarter mile stock.

I'm still breaking my new Si in so I haven't wanted to push it hard and time anything yet. I've cut it under 4-5k RPM at most during the break-in but I can say it has pushed me back in the seat with that torque. However, has anyone had a better run or have any insight as to why the car appears to underperform a bit vs the power it's putting out?

Is this true, 220 ft-lb of torque observed at the wheels and 205 HP at the wheels? (I'm mind blown)

 

[jayee]

Is this true, 220 ft-lb of torque observed at the wheels and 205 HP at the wheels? (I'm mind blown)

It will vary depending on several things like the individual dyno you use and elevation but generally yes Honda seems to have underrated their little 1.5T. People have been pulling stock wheel HP numbers close to what Honda rates it at the crank.

 

[Design]

Is this true, 220 ft-lb of torque observed at the wheels and 205 HP at the wheels? (I'm mind blown)

Yes and no. Vit uses a Dynapack which is incredibly consistent but may not accurately factor the absence of rotational mass. An average can be calculated, but the Si's wheels are comparatively heavier than most. It's probably a bit lower in real world driving (and matters less once modded).

By comparison, I believe KTuner ran their test Si through IMW's Dynapack. Their result looks to be around 180 HP/203 TQ at the hubs. Although I've yet to see one, I imagine a dynojet or mustang dyno would show HP & TQ readings a little closer together.

CN: I wouldn't get hung up about it.

 

[zroger73]

The new Accord 2.0T manual has the same issue. The acceleration numbers are almost identical to the SI.

I drove an Accord 2.0T 10AT and Civic Type R around a track earlier this week (among dozens of other vehicles ranging from a Corolla hatchback to a Mercedes-AMG GT-R). I plan on trading my Si for an Accord in the next few weeks.

Here I am flogging the Accord.

(Photo courtesy of Kevin McCauley)

 

[BoostedSiCoupe]

Is this true, 220 ft-lb of torque observed at the wheels and 205 HP at the wheels? (I'm mind blown)

I dont know about that. If those numbers are true, it definitely doesnt feel like it.

To me it feels pretty close to an 8th gen power wise, only slighly quicker. But not as much as those number would suggest.

 

[charleswrivers]

It'd be interesting to know what our cars would do in an instrumented test numbers-wise if you could run stock boost in it's torque limiting (inconsistent peak level) manner, but with all the quick enables selected and everything to aggressive II. The throttle being lazy and the turbo building boost noticable slower without these enabled is probably negating the otherwise superior power numbers.

 

[RODSCIVIC]

I drove an Accord 2.0T 10AT and Civic Type R around a track earlier this week (among dozens of other vehicles ranging from a Corolla hathback to a Mercedes-AMG GT-R). I plan on trading my Si for an Accord in the next few weeks.

Here I am flogging the Accord.

(Photo courtesy of Kevin McCauley)

Obviously you like it more than the Si, but can you provide insight on what it is that makes you want to move over to the Accord. Will you regret it when Acura comes out with the TLX Type-S?

 

[zroger73]

Obviously you like it more than the Si, but can you provide insight on what it is that makes you want to move over to the Accord. Will you regret it when Acura comes out with the TLX Type-S?

Last year, I wanted a reasonably-priced, economical vehicle with a manual transmission. The Civic Si checked all the boxes. The Civic Type R was (and still is) overpriced by the dealers and isn't as practical for use as a daily driver. The Accord was not out yet. I had intended to drive the Civic Si to work during the week and on the weekends while I was out running around with friends and family. I planned to only drive the Ridgeline when I needed to haul something, which is very rare. My brother and I both like to have beverages when we're out and about and the front cupholder situation in the Si quickly became an issue due to my arm either being on the armrest or my hand on the shift knob hindering access to the center console where the cupholders are. So, I drove the Ridgeline on the weekends and only drove the Si to work.

The Si got paint overspray on it from another business across the street from where I work right after I bought it. I finally tracked down the responsible party and was in the process of getting estimates to remove the overspray when the front passenger door and roof rail were vandalized. I was unable to recover damages, so the car sat for over four months before I finally decided to hire an attorney and pay out of pocket for now to have the car repaired, which will happen over the next week or two. This car has been bad luck and I want out of it. I'm not interested in buying another 2018 knowing that the 2019's are just months away nor do I typically buy the same vehicle sequentially.

I still believe the Civic Si is a better overall value than the Accord Sport 2.0T and is more capable in certain situations. The reality is that those situations rarely exist under safe and legal conditions on public roads. I don't track my vehicles, so I'm not able to push the Civic Si's limits. What I've found after driving these models on the track and on the street is that Accord Sport 2.0T is still more than capable despite the lack of an LSD, adaptive dampers, and stiffer components. At first, I thought I wanted the 6MT in the Accord, but the paddle shifters' ability to semi-permantly hold a specific gear in SPORT mode without it timing out still gives plenty of control - even if the foot action of the clutch is absent. Naturally, the Accord is also smoother and quieter and has more grunt than the Civic Si. The 1.5T is a great little engine, but the 2.0T is even better and feel more effortless and eager.

I also miss not having Honda Sensing and remote start in the Si like I do in my Ridgeline. The Accord Sport 2.0T 10AT has both along with an improved infotainment interface, LED head/fog lights, low-speed follow, traffic sign recognition, blind spot monitor, and a power driver's seat. Fuel economy isn't as good on the heavier and more powerful Accord, but it's tuned for regular fuel which offsets the higher price of premium I've been putting the Si, so fuel costs are a wash.

I think two primary factors have lead to this decision: 1) I rarely keep a vehicle more than 1-2 years and 2) the overspray and vandalism put a damper on my enthusiasm for my Si. If not for those two issues, I probably wouldn't be writing this post.

Will I regret buying an Accord when the TLX Type S appears? Probably not since it'll be time for another vehicle by then.

 

[NoelPR]

I still believe the Civic Si is a better overall value than the Accord Sport 2.0T and is more capable in certain situations. The reality is that those situations rarely exist under safe and legal conditions on public roads. I don't track my vehicles, so I'm not able to push the Civic Si's limits.

Boom my way of thinking everytime someone throws the "better handling" card.

 

[xbbnx]

Boom my way of thinking everytime someone throws the "better handling" card.

You dont have to drive a car balls to the wall on public roads or take it to a track to realize differences in handling. The Si is lighter, lower, stiffer, and has other suspension components intended for performance and therefore more nimble. Simple canyon twisties would show this without having to drive like a madman. That's where the "better handling card" argument comes into play, when both vehicles are taken through a canyon road which one comes more alive.

 

[jayee]

I still believe the Civic Si is a better overall value than the Accord Sport 2.0T and is more capable in certain situations. The reality is that those situations rarely exist under safe and legal conditions on public roads. I don't track my vehicles, so I'm not able to push the Civic Si's limits.

Boom my way of thinking everytime someone throws the "better handling" card.

I agree that the Accord is more than capable in being a daily driver, but you can feel that "better handling" in the Si even in "safe and legal conditions on public roads". Of course in the end it all depends on what you personally want out of the car. Although admittedly, I think most people who own an Si probably enjoy taking trips down to "Mexico" every now and then.

 

[Deleted member]

The latest Accord is an absolutely phenomenal vehicle- the best car in its class according to countless publications.

There are people who can't tell or don't care about or don't value the difference between the handling of a Prius and an 86. There is nothing wrong with that. But that doesn't mean there aren't people who do. The Si is made for people who value the driving experience more than economy, practicality, or comfort(even though the Si is pretty darn good in all those categories).

 

[jayee]

The latest Accord is an absolutely phenomenal vehicle- the best car in its class according to countless publications.

There are people who can't tell or don't care about or don't value the difference between the handling of a Prius and an 86. There is nothing wrong with that. But that doesn't mean there aren't people who do. The Si is made for people who value the driving experience more than economy, practicality, or comfort(even though the Si is pretty darn good in all those categories).

tl;dr - the entire Si vs Accord argument that has been going on in multiple threads can be summed up with:

The Si is a sporty car that can act as a family sedan.
The Accord is a family sedan that can be a sporty car.
Choose whichever suits your needs/preferences best.

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