GR Yaris New mods, guess the BHP?

[Duncan]

The GR is off for a fettle, will get the results in a few weeks.
Hardware will be:

Airtec IC and boost pipe kit
Panel filter, stock air box
Airtec turbo elblow
Kelford valve springs
Syvecs ECU
Tuned on 99 RON

Any predictions?

 

[kinboshi]

Have you got any drinks holders, stripes on the bodywork, or a gr-zoo.com sticker?

 

[Duncan]

Have you got any drinks holders, stripes on the bodywork, or a gr-zoo.com sticker?

That’s phase 2 for the extra 30bhp!

 

[kinboshi]

298bhp

 

[Michael Knight]

350bhp

 

[CommitConfirm]

What about the exhaust (OPF)?

I'll guess ~335-350

 

[MrJ]

Awh man, have the mods gone and left us again?

 

[Onehp]

342,5BHP corrected

I would at least add the HJS cat to that, if you want to stay clean/legal/quiet, should give an extra 15-20hp on this subtle configuration?

 

[Duncan]

True, but leaving the exhaust system stock for now incase I go G25 and have to run external waste gate.

 

[Tralien]

Kelford valve springs
Syvecs ECU

Thats the key to add more than 1,6 bar boost and keep torque up at 5000+ rpm, so I guess if you can run 1,7 or 1,8 you get close to 400 hp

But it will be hard with stock cat / exhaust to run that high boost

 

[Duncan]

Thats the key to add more than 1,6 bar boost and keep torque up at 5000+ rpm, so I guess if you can run 1,7 or 1,8 you get close to 400 hp

But it will be hard with stock cat / exhaust to run that high boost

In an ideal world I'd do something about the exhaust at the same time, but £ for £ I think the valve springs will do more than a HJS downpipes, hence going that route initially. Might test it without the GPF just to see the impact, but don't want to go all-out track car.

 

[Mintmansam]

320bhp,

Panel filter won’t do much
Unsure on turbo elbow maybe 5bhp?
Valve spring will stop valve float but won’t add power, slightly less as valve train losses have increased, but it is required
99 Ron I wouldn’t reckon will increase peak bhp, maybe mid range torque
ECU will allow more boost and other features so 300 - 310 on ECU?

I expect to see stronger mid range bhp increases than huge peak BHP numbers. Which for the road can be better than chasing peak BHP

I see nothing that would radically alter pressure drops/frictional losses to aid exhaust gas flow. And obviously no change in turbo either

 

[Mintmansam]

Thats the key to add more than 1,6 bar boost and keep torque up at 5000+ rpm, so I guess if you can run 1,7 or 1,8 you get close to 400 hp

But it will be hard with stock cat / exhaust to run that high boost

Stock turbo I doubt can maintain that boost above 5,000rpm Although I could be wrong. I would be surprised if I saw any car produce more than 360 on a stock turbo.

 

[Onehp]

I would be surprised if I saw any car produce more than 360 on a stock turbo.

MPS did 400hp on full turbo back, Wagner IC and 102ron + ethanol (30%?). Without E 380hp.
Stock turbo, stock intake and stock valve springs. Even if dyno would be optimistic (no idea), more than 360...

However on stock cat and exhaust system, EGT will run high and turbo will mostly make heat beyond a certain boost level...

 

[Duncan]

I think 340bhp without valve springs and stock cat has been shown to be the limit, for me I’m most interest to see how much more the turbo can flow over 5000rpm with the uprated springs in. Probably not a lot, but it’s more about future proofing for a hybrid later on.
I think the Motive garage guys showed a 14kw gain from spring, but not clear as they added ethanol at the same time. That’s the only data I’ve seen.

 

[Steve]

Won’t stiffer valve springs actually reduce power? They’re only necessary for negating valve float at high engine speed I thought.

Panel filter won’t do anything, other than draw crap into the intake, if it’s a foam one.

99 RON almost undetectable over the standard 98 RON map, maybe 1-2 bhp.

Almost all of the power increase will be from increasing boost with the replacement ECU, so that is totally dependent on the map you choose and how hard you want to work the original components. Could go 370 bhp+ for a good while I imagine.

 

[Duke]

Springs are surely only going to increase power (prevent loss of, really) if you’re already suffering float at high rpm?

 

[Duncan]

Springs are surely only going to increase power (prevent loss of, really) if you’re already suffering float at high rpm?

All tuners using standalone ECUs so far have reported boost has to be reduced above 5/6k rpm to avoid float (down to ~1.3 bar) So if this can be avoided and say 1.8 bar be maintained then there should be a power gain at the top end. Question then is can the stock turbo flow that much or would it run out of puff anyway.

 

[Tralien]

Thats the point. With Syvecs you could do 1,8 bar boost but you cant do with stock springs. So the power comes from the boost, not the springs....and I didnt see an engine with stock turbo and 1,8 bar, so very exciting to see what you gain.

 

[Onehp]

Earlier referred MPS with 380 or 'safe' 370hp on 102ron, they run 1,6 bar flat basically on stock valve springs. May very well be on or over the limit... Also nothing in the exhaust, 'cool' but very dirty and highly illegal in Germany....

Try the auto subtitle function if not understanding German:


If valvesprings, personally I like the pumaspeed turbo, not much bigger but with WRC core in combination with a metal catalyser would be nice balance of power, response and relative reliability.

PS: @Duncan when opening up the head, maybe put in better camshafts in while at it? Kelord have a set that is similar to stock but that hasn't got the pressed on lobes than can shift as they did on the Fensport sprint car...