GR86 Engine pulls harder at part throttle???

[ninjin]

Something I've on my car is that the car seems to pull harder in higher gears, say 4,5,6th at part throttle (pedal 50% of travel) compared to pedal to the metal.

Example: doing 50mph in 6th, car feels to accelerate harder with part throttle compared to full throttle.

This has not been verified with timing gear just the feel I get from the drivers seat.

Anyone else find this?

 

[Conscript]

The pedal doesn't really do anything past about halfway. Perhaps you're just feeling that?

It's annoying. They seem to have made the pedal very sensitive for the top of the travel to make the car feel quicker low down but the flip side is that it's a bit disappointing that pushing it all the way to the floor doesn't really result in more power.

 

[Beans]

The pedal doesn't really do anything past about halfway. Perhaps you're just feeling that?

It's annoying. They seem to have made the pedal very sensitive for the top of the travel to make the car feel quicker low down but the flip side is that it's a bit disappointing that pushing it all the way to the floor doesn't really result in more power.

I agree with this.

I prefer driving around using half the throttle pedal , gives the perception there's more (when there isn't )

 

[Gibbo78]

Perhaps that revised mapping that Toyota have announced might help…. Perhaps….maybe……

 

[Itcaptainslow]

Perhaps that revised mapping that Toyota have announced might help…. Perhaps….maybe……

The revised mapping that we can’t get?

 

[ninjin]

At least I'm not going crazy and others have the same feel! But I do feel that if I mash the throttle, it seems to pull weaker than 50% throttle. If the throttle did nothing more after 50%, I shouldn't feel less power right?

 

[Gibbo78]

You would have thought they would have nailed this given the R&D given it is a GR product.

 

[Gibbo78]

The revised mapping that we can’t get?

Aye that one….

 

[SckSqzBngBlo]

At least I'm not going crazy and others have the same feel! But I do feel that if I mash the throttle, it seems to pull weaker than 50% throttle. If the throttle did nothing more after 50%, I shouldn't feel less power right?

Your WOT may trigger open loop control part of the map which may have less ignition timing, but i wouldn't think it would happen just after 50%.

Sometimes on na cars there is a sweet spot for air speed. My 09 Honda civic has some weird ram air effect if you find the sweet spot, acts like 1-2psi of boost I swear it.

 

[Jianlun]

At least I'm not going crazy and others have the same feel! But I do feel that if I mash the throttle, it seems to pull weaker than 50% throttle. If the throttle did nothing more after 50%, I shouldn't feel less power right?

I get that also. And it bugged me enough to find a reason in the stock tune (which i used VF Tuner to read) but i cant find any smoking gun.

FWIW here is a screenshot of the Target AFR vs load for the WOT mode (bottom right) and 3x lean mode (there are 4 lean maps in total, not sure what is what, 3 of them are shown).

For now, to sleep at night, i put it down to expectations vs reality problem. You expect more when you WOT, but you dun get more, and the brain starts mindf**king.

 

[ZN8]

I dont think thats something isolated to our cars. Butterfly valves in throttle bodies aren't linear. I can't say I've driven a car where past halfway is a massive difference in power.

 

[SckSqzBngBlo]

My old Megane Trophy had throttle maps you could select including linear which was awesome, made it feel more like cable throttle.

 

[Infinity]

Yes we have noticed with our car too.
We also recorded an inconsistency in power delivery at the mid-high rpms and data logged ignition timing

The throttle mapping is very aggressive and could do with a more linear map.

 

[Chris Mc]

Max Nm’s is at 3700k rpm, which is bang in the middle of the range you’ve mentioned.

 

[Jianlun]

Something I've on my car is that the car seems to pull harder in higher gears, say 4,5,6th at part throttle (pedal 50% of travel) compared to pedal to the metal.

Example: doing 50mph in 6th, car feels to accelerate harder with part throttle compared to full throttle.

This has not been verified with timing gear just the feel I get from the drivers seat.

Anyone else find this?

I felt part throttle pulling harder also. Was so curious that i dyno-ed it hahaha.

Red is full stock exhaust (with GR intake, stock tune, no other power mods, i posted it before).
Green is MAP headers (with same GR intake, stock tune)
Pink is MAP headers (with same GR intake, stock tune), but with my throttle pedal position at around 70 to 80% for most of the run, where ECU will command closed loop fueling at 14.7 afr.

Yes the MAP header sucks, will try to do a tune next. Probably VVT etc are out of whack with the headers being 4-1 vs stock 4-2-1. But thats beside the point here.

Point is part throttle does show a slight reduction in power pink vs green. But not much. But definately not more than full throttle.

Also attached OBD2 logs (AFR vs rpm and pedal position vs rpm) of the pink. Shows the AFR staying close to stock. Pedal is recorded as 40 to 45%, but pedal is 10% (no throttle) to 55% (WOT). So rhe recorded 40% to 45% is kinda 70% actual throttle pedal position.

 

[Noel McC]

Race Chip+ XLR5 Throttle Controller helps sorts pedal a bit. Though the awful and more annoying terrible stuttering-juddering-kangarooing (stammering lurching) acceleration still happens at times. That I think needs sorted out by remap, that we are not getting?

 

[GRistopher]

Race Chip+ XLR5 Throttle Controller helps sorts pedal a bit. Though the awful and more annoying terrible stuttering-juddering-kangarooing (stammering lurching) acceleration still happens at times. That I think needs sorted out by remap, that we are not getting?

This has been a topic of much discussion on the forum before. There are a few things that have been blamed for it.

When the engine is cold it seems pretty obvious to me that it's the engine switching between it's awful cold start mode and regular throttle map as you apply the throttle - this is made obvious if you have a noisy exhaust and can hear the transition.

I dont notice it as much when the engine has warmed up. Some members have fitted diff braces or other stiffening mods and claimed that it helps.

The oversensitive throttle probably plays it's part too, exacerbating kangarooing as the drivers foot gets lurched back and forth, although if you're claiming it still happens with the XLR5 this might not be the case for you.

I guess what I'm saying is that, as a forum, we have collectively complained about these symptoms, but aside from the ones related to the engines cold start procedure, we haven't got any definitive answers.