[Mk2] [Turbo] r/r graph before and after fitting xs power i/c and disabaling tvis

[redmr89]

ive read a few posts over the years wondering what xs power i/c's do to the bhp. and what happens when you disable the tvis butteflys,

so im on holiday and bored so thought id go down the rolling road.



the black lines are 2 years ago with the standard ic and tvis working
the red lines are today, xs power smic installed and tvis dissabled

4bhp extra on top end ( not a lot ). but more bhp and torque through the range.

@4200rpm an extra 15hp and nearly 30 extra lbs/ft torque..

so im my eyes deffo worth doing especialy as disconecting the tvis costs nowt. and an xspower i/c less than £100.

not a very scientific test i know, but its the same car, same rollers, same outside temp. so not a bad comparison.

if i could just get round to sorting out why my overall figuer is low both times then id be a happy bunny. ( probably cos its overfueling )

specs.

rev1
ct20b
blitz lm filter
hyper sr downpipe
aas s/s exhaust
xspower smic
magnecor plugs
ngk colder grade plugs.
grainger valve @ 1.1 bar
fcd

[jon_st205]

The thing is that with TVIS disabled (open all the time) you are quite seriously compromising power/torque low down. I doubt the better mid range is down to this mod either, much likely it's simply a function of higher boost & lower inlet temp.

The curves are very messy but really you need your AFR & boost level plotted on the same graph to understand why. Clearly it's likely to be overfuelling badly, but you also need to check how stable the boost is with the relief valve.

Jon

[jimGTS]

for someone running a ct20b at 1.1bar and only making 220flywheel horsepower, everything alright with the engine?
the graph seems VERY wavyto.

boost and af would help.

bare in the mind the tvis butterflies open as soon as it sees boost, so tvis working or not doesnt mean a great deal of difference.
IF you can control the tvis, then sure you can gain a little bit more low end.

[redmr89]

for someone running a ct20b at 1.1bar and only making 220flywheel horsepower, everything alright with the engine?

other than the graph. the car runs really well. altho my fuel economy is shocking. so im busy looking for a new lambda sensor.

maybe i need to replaice the afm too.

and an ebc is on the cards to replaice the mbc. in car control

[tarmac terrorist]

controling the tvis is pointless as toyota got it about right as for removing it i did but only cos it becomes a restriction when your running higher power, as for yours i would of left it on mate i ran 355 fly on 440cc & still running tvis with the ct26 hybrid

[Ren0W]

What about changing the time/moment (rpm's) the tvis opens?

The intake manifold and TVIS were designed to provide good low end torque and high top end flow using a dual runner per port setup with a set of butterfly valves kept closed at low RPMs to increase air velocity into the port and open at higher RPMs to increase flow capacity. The proper TVIS opening point lowers as VE improves (better exhaust, turbo, valves or cams). The ECU keeps a fixed opening point around 4200RPMs which is too high for modified engines. Consequently, there will be a torque dip from around 3800 RPMs to 4200 RPMs. The ECU also uses the TVIS to reduce engine VE if it has detected knock in the recent past. This can cause variations in performance for no apparent reason. The TVIS be kept functional as long as you continue to use the stock intake manifold but you should control the TVIS with an MSD RPM switch. You will need to purchase an MSD 8950 along with an appropriate RPM module, which is going to be included in wither the MSD 8743 (for even 100 RPMs) or MSD 87431 (for odd 100 RPMs) opening points. Alternatively, you can make your own fully adjustable RPM module. Most modified 3S-GTEs will need to open the TVIS between 3600 and 3900 RPMs. The only way to know for sure is to do a dyno pull to 4500RPMs with the TVIS open and another one with the TVIS closed keeping everything else the same. Then, the point at which the two torque curves cross is your best opening point.

[tarmac terrorist]

What about changing the time/moment (rpm's) the tvis opens?

The intake manifold and TVIS were designed to provide good low end torque and high top end flow using a dual runner per port setup with a set of butterfly valves kept closed at low RPMs to increase air velocity into the port and open at higher RPMs to increase flow capacity. The proper TVIS opening point lowers as VE improves (better exhaust, turbo, valves or cams). The ECU keeps a fixed opening point around 4200RPMs which is too high for modified engines. Consequently, there will be a torque dip from around 3800 RPMs to 4200 RPMs. The ECU also uses the TVIS to reduce engine VE if it has detected knock in the recent past. This can cause variations in performance for no apparent reason. The TVIS be kept functional as long as you continue to use the stock intake manifold but you should control the TVIS with an MSD RPM switch. You will need to purchase an MSD 8950 along with an appropriate RPM module, which is going to be included in wither the MSD 8743 (for even 100 RPMs) or MSD 87431 (for odd 100 RPMs) opening points. Alternatively, you can make your own fully adjustable RPM module. Most modified 3S-GTEs will need to open the TVIS between 3600 and 3900 RPMs. The only way to know for sure is to do a dyno pull to 4500RPMs with the TVIS open and another one with the TVIS closed keeping everything else the same. Then, the point at which the two torque curves cross is your best opening point.

not shore mate ,not seen that post before interesting though, people have also tried this idea on the vvtli on celica 190s & they actualy loose around 15hp i suppose the only thing would be to play with it & see what happens to the power figures

[redmr89]

well all i can say about tvis is when i drove the car with it working the car would boost hard till about 4000rpm then it felt like it was just rolling along until 5000 rpm when boost would kick hard again. till redline

with tvis disabled. boost kicks in and stays hard till redline.

altho my dyno does say with and without tvis that there is a dip in torque between 4k and 5k . so maybe theres something else going on?? id love to get to the bottom of it.

[tarmac terrorist]

well all i can say about tvis is when i drove the car with it working the car would boost hard till about 4000rpm then it felt like it was just rolling along until 5000 rpm when boost would kick hard again. till redline

with tvis disabled. boost kicks in and stays hard till redline.

altho my dyno does say with and without tvis that there is a dip in torque between 4k and 5k . so maybe theres something else going on?? id love to get to the bottom of it.

i think you have other issues mate that you need to get to the bottom of good luck, i know how you feel these things can be frustrating

[tarmac terrorist]

with the grainger valve fitted have you removed the vsv ??

[redmr89]

yeah ive disconected the vsv. and i now have a ebc just need to get it fitted

[toyokid]

"i ran 355 fly on 440cc & still running tvis with the ct26 hybrid"

Sounds a little high on 440s',
haven't heard of this much before?
What A/F ratios were you running?
An optimistic dyno?

Stephen

[tarmac terrorist]

"i ran 355 fly on 440cc & still running tvis with the ct26 hybrid"

Sounds a little high on 440s',
haven't heard of this much before?
What A/F ratios were you running?
An optimistic dyno?

Stephen

there were a few guys there on the day frank,bry ,mark & jim along with a few others they all saw it produce it (this was with 87.5mm pistons & i port matched the head also)other than that standard 440cc & standard fuel pump
here is the run
www.youtube.com/watch?v=sDxUHDQxK78

[RobCrezz]

"i ran 355 fly on 440cc & still running tvis with the ct26 hybrid"

Sounds a little high on 440s',
haven't heard of this much before?
What A/F ratios were you running?
An optimistic dyno?

Stephen

there were a few guys there on the day frank,bry ,mark & jim along with a few others they all saw it produce it (this was with 87.5mm pistons & i port matched the head also)other than that standard 440cc & standard fuel pump
here is the run
www.youtube.com/watch?v=sDxUHDQxK78

What did it make at the wheels? Engine advantages is pretty optimistic for flywheel figures.

[jimGTS]

Ea were generous for sure.
From what I remeber nick hit 282atw with a meaty ct26 hybrid

I would imagine the 440s were running 100% duties and leaned out the afs to near perfect fueling to hit those numbers.

Certainly the most I've seen on 440s in the uk.
But yeh 355fly was generous. Prob nearer 330-340 in reality.
Still great tho.

[tarmac terrorist]

cant remember what wheel horse power was ,will check & post the dyno sheet in the next couple of days for you,although the best thing i ever done was get rid of hybrid ct26 it used to spool like a gt40 turbo but never gave the power of one lol,so happy with the gt3076 cant wait to get it mapped next year see if i can get the 500 fly this time round had 455 fly before with 405 whp (at perfect touch) so we will see fingers crossed

[toyokid]

Hi

As a matter of interest,
what was the spec of the Hybrid?

One would assume a CT20b would be capable of those figures?

Any thoughts?

Thanks in advance.

Stephen

[tarmac terrorist]

it was a turbo technics stage 1 rated to 380hp same one as mark edwards had on his mate

[toyokid]

Hi

Do you have any comparison of this turbo v CT20b?

Curious

Stephen

[tarmac terrorist]

im sorry i dont mate but will try to find something,personally i wouldnt go for one of these at the time many years ago it was the only thing i could afford as garretts were around the 3 to 4k range