Kane76

Senior Member
Joined
Sep 16, 2015
Threads
1
Messages
83
Reaction score
28
Location
Los Gatos
Car(s)
2009 TL
For me because 1) less responsive and 2) lower redline. With a nice revving NA engine you can actually use the throttle to control the car on turns because it's responsive enough to do so. Not quite as easy or fun with a turbo engine.

 

Design

Senior Member
Joined
Sep 28, 2015
Threads
27
Messages
3,255
Reaction score
2,838
Location
Southern California
Car(s)
09 MS3, 17 ABM Si Sedan
Country flag
You guys may be pleasantly surprised at how far modern tuning has come. Look at any review of the 2016 CTR and you'll see some surprising revelations on driving behavior. With enhancements to DBW and NLS; lag is just about nonexistent in smaller turbos - even when downshifting. Although I can appreciate the power we can wrangle from an NA 2.0/2.4, it's no longer a practical nor highly flexible motor when matched with the competition. With turbocharging you get 80% of available torque as low as 1.5K.

Then again, maybe I'm just spoiled after driving the MS3 for so many years. :D
 

G26okie

Senior Member
Joined
Oct 1, 2015
Threads
7
Messages
301
Reaction score
143
Location
Florida
Car(s)
2016 Accord EX-L V6 Sedan
You guys may be pleasantly surprised at how far modern tuning has come. Look at any review of the 2016 CTR and you'll see some surprising revelations on driving behavior. With enhancements to DBW and NLS; lag is just about nonexistent in smaller turbos - even when downshifting. Although I can appreciate the power we can wrangle from an NA 2.0/2.4, it's no longer a practical nor highly flexible motor when matched with the competition. With turbocharging you get 80% of available torque as low as 1.5K.

Then again, maybe I'm just spoiled after driving the MS3 for so many years. :D
The ms3 has quite the low end thats for sure. 280lbs of torque at 3000rpm. I wish I never modded it, but I had gone to far with it.
 

mvance30

Senior Member
Joined
Oct 12, 2015
Threads
4
Messages
184
Reaction score
68
Location
NJ
Car(s)
15 si
remember its not super easy to make decent power in an NA 4 cylinder. while its possible, its not always cost efficient and even when looking at the s2k that was in a higher priced rather limited vehicle. while the SI isn't selling like crazy they do sell more than s2ks when they were around.
 

Nurburgring

Member
Joined
Oct 21, 2015
Threads
1
Messages
8
Reaction score
9
Location
Chile
Car(s)
Exige, 911, Civic
The small 1.5 turbo is generating just 174hp at 16 psi of boost, which is a pretty poor power output figure for a turbocharged engine. This is because of the compromises that were made during engine design: Long stroke, integrated exhaust manifold with water cooling, small single scroll turbine, high-tumble intake ports, low redline, eveything on this engine has a fuel economy and low emissions focus.

If we asume the Si´s power target will be between the EX-T and the Type R, that would mean around 240hp, but lets say Honda stays conservative and it ends up with 220hp. To generate that, the small 1.5T would need to be pushed with at least 24 psi of boost, or a significantly larger turbine which would make the powerband look like an 80´s turbocharged engine.

So yes, I agree with the people thinking Honda will use the 2.0T from the Type R in a detuned state.
 


G26okie

Senior Member
Joined
Oct 1, 2015
Threads
7
Messages
301
Reaction score
143
Location
Florida
Car(s)
2016 Accord EX-L V6 Sedan
The small 1.5 turbo is generating just 174hp at 16 psi of boost, which is a pretty poor power output figure for a turbocharged engine. This is because of the compromises that were made during engine design: Long stroke, integrated exhaust manifold with water cooling, small single scroll turbine, high-tumble intake ports, low redline, eveything on this engine has a fuel economy and low emissions focus.

If we asume the Si´s power target will be between the EX-T and the Type R, that would mean around 240hp, but lets say Honda stays conservative and it ends up with 220hp. To generate that, the small 1.5T would need to be pushed with at least 24 psi of boost, or a significantly larger turbine which would make the powerband look like an 80´s turbocharged engine.

So yes, I agree with the people thinking Honda will use the 2.0T from the Type R in a detuned state.
I don't think that is horrible, most OEM turbo cars run pretty high boost. The Fiesta ST's boost peaks at 21-22psi to get 200hp from its 1.6 liter.
 

Nurburgring

Member
Joined
Oct 21, 2015
Threads
1
Messages
8
Reaction score
9
Location
Chile
Car(s)
Exige, 911, Civic
I don't think that is horrible, most OEM turbo cars run pretty high boost. The Fiesta ST's boost peaks at 21-22psi to get 200hp from its 1.6 liter.
Normal boost for the 1.6T EcoBoost is 18.9 psi, with a lower compression ratio than the Honda engine, and it´s making a lot more torque and power (graph is at the wheels on a dynojet). It does have an overboost mode to 21 psi but the small Borg Warner KP39 will never be able to sustain that over 5000rpms.

fe_1023133_600.jpg
 

Design

Senior Member
Joined
Sep 28, 2015
Threads
27
Messages
3,255
Reaction score
2,838
Location
Southern California
Car(s)
09 MS3, 17 ABM Si Sedan
Country flag
Another thing worth mentioning is that most modern setups use VGT to mitigate throttle response at low RPMs. Essentially it allows larger turbos with adjustable vanes to behave like smaller ones at low RPM.
 

Nurburgring

Member
Joined
Oct 21, 2015
Threads
1
Messages
8
Reaction score
9
Location
Chile
Car(s)
Exige, 911, Civic
VGT is not common yet in gasoline engines, first application was the 911 997.1 Turbo in 2007 IIRC, not many other manufacturers have followed. But most modern turbodiesel engines use them.

Honda is not using VGT nor twin scroll in their 1.5T and 2.0T, but they´re fighting lag with VTC tricks and short exhaust manifold tracts.
 

Design

Senior Member
Joined
Sep 28, 2015
Threads
27
Messages
3,255
Reaction score
2,838
Location
Southern California
Car(s)
09 MS3, 17 ABM Si Sedan
Country flag
It's actually been around since the 80s IIRC. I bring it up because the RDX used this approach in conjunction with VTC.

Haven't seen much literature on the CTR 2.0T specs. But would be disappointed if they are not in fact going with a twin scroll. :(
 


Razer

Senior Member
Joined
Sep 11, 2015
Threads
1
Messages
97
Reaction score
78
Location
Midwest
Car(s)
Honda HR-V
The 1.5t also have very small slender connecting rods, people looking at it think it will be fine in the current application but say that is probably has very little overhead. Combine that with the other items mentioned above and the 1.5t does not seem like even a remote option at this point any longer. Which I'm actually very glad for!
 

Nurburgring

Member
Joined
Oct 21, 2015
Threads
1
Messages
8
Reaction score
9
Location
Chile
Car(s)
Exige, 911, Civic
Haven't seen much literature on the CTR 2.0T specs. But would be disappointed if they are not in fact going with a twin scroll. :(
Honda official statement:

Combining a turbocharger with Honda’s VTEC and Dual-VTC technologies provides a number of benefits in output, efficiency and packaging. Dual-VTC allows a degree of valve timing overlap which is finely controlled across a broad rev range to improve responsiveness and efficiency. VTEC varies the degree of exhaust valve lift to reduce turbo lag through increased exhaust pressure at lower rpm while delivering a high output at higher rpm. As a result of the benefits these technologies bring, a mono scroll turbocharger can be used to produce a class-leading peak output, while maintaining response at lower engine speeds and a high-revving power delivery. In order to further improve responsiveness, the turbocharging system incorporates an electronic wastegate which offers a higher degree of freedom in induction pressure control over a conventional unit.

(BTW, K20C1 has only exhaust side VTEC, dual VTC).


the 1.5t does not seem like even a remote option at this point any longer. Which I'm actually very glad for!
+1!
 

G26okie

Senior Member
Joined
Oct 1, 2015
Threads
7
Messages
301
Reaction score
143
Location
Florida
Car(s)
2016 Accord EX-L V6 Sedan
Normal boost for the 1.6T EcoBoost is 18.9 psi, with a lower compression ratio than the Honda engine, and it´s making a lot more torque and power (graph is at the wheels on a dynojet). It does have an overboost mode to 21 psi but the small Borg Warner KP39 will never be able to sustain that over 5000rpms.
And even though it has more hp/torque, the new civic seems to match it in 0-60 and 1/4mile times/trap speed according to car and driver.
 

Tuttle

Senior Member
Joined
Apr 2, 2015
Threads
3
Messages
140
Reaction score
43
Location
Virginia
Car(s)
CBR600RR
This might not seem ideal as broad power is a desirability of modern turbo and might seem to have lag, but most modern turbo motors don't pull as well above 6k. Still, it'd be fast and would maintain the typical high revving nature of the Si.
So true :( And even turbos engines that have relatively high redlines (> 7000 rpm) aren't worth revving out since torque plateaus much earlier. You end up short shifting which defeats the purpose of having a high redline.
 

Nurburgring

Member
Joined
Oct 21, 2015
Threads
1
Messages
8
Reaction score
9
Location
Chile
Car(s)
Exige, 911, Civic
The Type R engine does not have the typical turbocharged engine power delivery. Granted, it does not rev high, but power is still climbing up to 6600rpms, not flat like a table by 5500 like many others, and torque peaks quite late in the powerband. Now, the Si, who knows.

K20C1 dyno:


 

 
Top