Kia Forte Turbo Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
458 Posts
Discussion Starter · #1 ·
I know we don't have VTEC but at what RPM range does boost go maximum? My butt dyno felt a surge of power around 4,000RPM. I get really envious of those big power cars on Youtube where you see their speedometer needle just climb like a mother fucker. Even though the butt dyno makes it feel like you're going really fast, when you look at the needle it's just creeping, lol.

Anyway, I was in 4th gear and around 3,000RPM when I got 75% - WOT and the car puts your a bit back into your seat but like I said, when you look at the needle it isn't crazy like those Youtube videos of those torquey Mustangs or TT Surpas. Nice to dream, though.
 

·
Premium Member
Joined
·
3,021 Posts
Our boost actually hits at 1750 and is supposed to have a liniar pull to 5500-6k. The surge is normal for our car with stock tune.
 
  • Like
Reactions: PLP

·
Registered
Joined
·
1,067 Posts
Omg........
 
  • Like
Reactions: lephoenix

·
Registered
Joined
·
458 Posts
Discussion Starter · #5 ·
Our boost actually hits at 1750 and is supposed to have a liniar pull to 5500-6k. The surge is normal for our car with stock tune.
I know boost comes early but what's the cause of the surge? I'm guessing the boost levels varies through the RPM and around 4,000RPM it hits 18psi or whatever the max is.
 

·
Premium Member
Joined
·
3,021 Posts
It should hit 18psi lower then that. Mine always hit 18 around 2200. The surge was tracked down to the tiny i.c piping and the i.c itself. If your feeling a surge in power like it woke up then you might have a weak stock bpv
 

·
Registered
Joined
·
516 Posts
Back when vtec was a hot topic it was because the technology was pretty fresh.
It is basically like having a normal street cam for regularly driving but switches to a hot cam profile for high rpm acceleration.
Since it was newer back then there was a very noticeable change in performance when it kicked it. Same with single scroll turbos and lag back in the day.
Car people liked it. The average person maybe not so much.

Most cars have variable valve timing now. And we also have a variable turbo. Maybe more variable stuff. I don't know. But it all means that the manufacturer can make a little motor feel like a smooth bigger motor. Not as much fun but smoother and more efficient. Or at least that's the idea.

Make tork or a tuner can talk more about our valve timing but our turbo can, if all external variables are correct, make full boost at 1750 rpms.
If a motor nanny says no then it might pull timing or boost until a bit later. And it's my understanding that our motor has more nannies than a Welsh prince. But on rare occasion the nannies get into the wine and let the motor shit itself.
 

·
Premium Member
Joined
·
1,035 Posts
It should hit 18psi lower then that. Mine always hit 18 around 2200. The surge was tracked down to the tiny i.c piping and the i.c itself. If your feeling a surge in power like it woke up then you might have a weak stock bpv
I would love to see a datalog showing 18psi at 2200 rpm. Or a video of the tachometer and a boost gauge, I find this really hard to believe.
 

·
Premium Member
Joined
·
3,021 Posts
I would love to see a datalog showing 18psi at 2200 rpm. Or a video of the tachometer and a boost gauge, I find this really hard to believe.
Go ahead and log it lol. I'm not stock tune and mine is set to give full boost at 2500 to 3k so I don't spin lol. I have talked to others that have said right about 2200-2500 they hit 17-18 at wot. I can't say they have since I haven't seen logs yet I am just going off what I have been told.
 

·
Registered
Joined
·
481 Posts
I'm tuned and was on the freeway and a Mustang thought he would try, started pulling away and then the car felt like it hit vtec... I'm used to Hondas so this kinda startled me to be honest.... But I've had some weird miss fire etc lately so...
 

·
Premium Member
Joined
·
1,035 Posts
Go ahead and log it lol. I'm not stock tune and mine is set to give full boost at 2500 to 3k so I don't spin lol. I have talked to others that have said right about 2200-2500 they hit 17-18 at wot. I can't say they have since I haven't seen logs yet I am just going off what I have been told.
Whenever you can I'd love to see it. I know you have the tune, and I'd just like to see it actually doing that.
 

·
Registered
Joined
·
1,697 Posts
Whenever you can I'd love to see it. I know you have the tune, and I'd just like to see it actually doing that.

It should hit 18psi lower then that. Mine always hit 18 around 2200. The surge was tracked down to the tiny i.c piping and the i.c itself. If your feeling a surge in power like it woke up then you might have a weak stock bpv


So do we have any graph, map or anything as such showing boost pressure at WOT vs RPM?

I feel mine is weak. I hit maybe 13-14 PSI (from Torque app/MAP) at 2000 RPM. Sometimes, very rarely, I can hit 17.8 (once or twice 18.1) near 4000 RPM.
Funny is that the pressure is not consistent. There are days it is stronger and other times (mostly those...) weaker.

Therefore, if you guys have access to data showing what the pressure could, or should be, please share it.


I am trying to talk to my dealer who's NEVER seen Forte SX. They never sold one, they never serviced one. Hence, they knowledge is limited. Similar to Optima Turbo. Not really good seller there (I guess they only go lowest price cars).
 
  • Like
Reactions: Forte5

·
Registered
Joined
·
253 Posts
Not traditional VTEC like a Honda.

The Forte 1.6 and 2.0 have a twin VVTi. This means that the intake cam and exhaust cam can be rotated both advance and retarded depending on engine conditions. This is why the 1.6 engine can generate so much torque and still make peak power at 7,000 RPM. The actual cam profile is very small on the 1.6 engine, but its the VVTi that will allow the engine to make big power and torque from such a small cam profile.

Ford uses a very similar system in the new 5.0 GT, thus allowing huge power to be made from N/A application.

The ECU has a very complex operation and load out for the cam VVTi function, that I would let John go into more detail if needed.

Thanks,

Gina
 

·
Premium Member
Joined
·
3,021 Posts
So do we have any graph, map or anything as such showing boost pressure at WOT vs RPM?

I feel mine is weak. I hit maybe 13-14 PSI (from Torque app/MAP) at 2000 RPM. Sometimes, very rarely, I can hit 17.8 (once or twice 18.1) near 4000 RPM.
Funny is that the pressure is not consistent. There are days it is stronger and other times (mostly those...) weaker.

Therefore, if you guys have access to data showing what the pressure could, or should be, please share it.


I am trying to talk to my dealer who's NEVER seen Forte SX. They never sold one, they never serviced one. Hence, they knowledge is limited. Similar to Optima Turbo. Not really good seller there (I guess they only go lowest price cars).
I have those days to. Car will feel really good and run perfect and then the next day or time I drive it and give same boost and throttle it feels sluggish. I have talked to Tork about this and he is working on it and says it's in the ecu.
 

·
Registered
Joined
·
1,697 Posts
I have those days to. Car will feel really good and run perfect and then the next day or time I drive it and give same boost and throttle it feels sluggish. I have talked to Tork about this and he is working on it and says it's in the ecu.
so did any piping help?
your previous posts suggest you were hitting 18 PSI and held across the whole band.

I need to finally install a mechanical boost gauge to see true values as all readbacks are from Torque via MAP. Maybe MAP is faulty?
 

·
Premium Member
Joined
·
3,021 Posts
The diy hot pipe did help a little. I would still hit the same boost but wouldn't pull as hard at times. Seems like these motors or ecu is touchy for some reason.
 
1 - 16 of 16 Posts
Top