Takeda Intake And H&s Exhaust Update...

[fjcfarrar]

I don't disagree with anything you say except that gaining something like 50 or so BHP is going to give only an imperceptible change in how it drives. Already top speed and acceleration are both limited by rear tyre grip with the wheels running faster than the speed achieved because of straightforward slip between tyres and tarmac. At the same time an extra 50 BHP on tap is never going to be a big disadvantage. The degree of restriction imposed by the ISF exhaust system is not great enough for a system with slightly less restriction to benefit performance but may be really worth it for a fuller V8 sound. As for induction, I have never found induction roar to be very exciting and systems which aim to improve power or efficiency by cooling the air entering the engine to increase its density rarely work in practice because the air enters the engine and is then heated within the manifolds etc. before entering the combustion chambers such that having it a bit cooler at entry to the manifolds is swamped by the very large heat sources between there and the combustion chambers. Maybe separately refrigerating the incoming air could produce more worthwhile gains, but even these would be offset by the power taken up in refrigerating the air.

Our friends in the USA have gone to town with many power-improving modifications which are effective but do not provide pro-rata improvement in the car's performance. I suspect they are happy just to burn tyres quicker. More power leads on along the path of improving suspension, brakes and tyres until a completely different car is born......

None of this is intended to spoil anybody's effort to make their car suit them better but to contain a reminder that genuine performance improvements generally don't come from cheap induction and exhaust trinkets and low-cost tweaks - when I say cheap, not in actual £sd but as a proportion of the cost of real, significant improvements. Even these come with the rider that significantly increasing power output from any particular engine comes at the expense of its life and reliability.

[Peter P18]

Hey Stu.

Managed to print off a PDF fitting guide from the States for the Takeda intake. :)

Did you disconnect your Battery when you did your installation? Couldn't really tell from the YouTube video if they did or not??

Just thinking it's a pain to loss the different settings if I don't really need to! ;)

Pretty sure I've not disconnected the Battery for other induction kits on things like the Supra??

[Stuno1]

I didn't bother. Mine was dicsonnected afterwards when i charged the Battery though.

Can't hurt to do it though as the ecu needs to learn the difference with the new intake added.

Stu

[Peter P18]

Cool. Was it pretty straightforward sorting out the windows etc after you reconnected it?

Know it's in the handbook (in the office at the moment).

[Stuno1]

Yup, wind every one half way down (from its own control), then wind them up holding the switch on the second notch until the window is closed and you hear a click. You will then be able to control them as before from the drivers side controls.

Stu

[Peter P18]

Perfect! Thanks Stu. :)

[Stuno1]

Could you do a sound clip with it installed from inside the car? That would complete all the varieties from this thread in terms of giving people a full understanfing of the sound impact of the intake/exhaust/stock etc

When i get the wheels etc done on my car i get a pic of the underside so people can see the exhaust as well.

Stu

[Peter P18]

Guess that would be a nice last touch Stu. :)

I'll probably try and do a couple of videos of mine with just the Takeda installed. Don't think you had a chance to do that, what with the delay in yours arriving, and the exhaust already having been fitted etc.

[Stuno1]

Guess that would be a nice last touch Stu. :)

I'll probably try and do a couple of videos of mine with just the Takeda installed. Don't think you had a chance to do that, what with the delay in yours arriving, and the exhaust already having been fitted etc.

Exactly.

[Stuno1]

Right. Filmed under the car. There are 2 pipes. One for each back box. The second cat has been removed and each pipe goes in to one of the pre cats.

Stu

[Peter P18]

Nice. :)

Makes sense to have it designed that way. Removing the second cat will free up some ponies for sure. ;)

As a few of us now know, it sounds lovely in the flesh!! :)

[Stuno1]

Quite intrigued to see what bhp it reads on a rolling road now I know the cat has been removed and coupled with the intake.

Stu

[noby76]

Wow looks and sounds good Stu just like how a performance V8 should :) .. should have dyno'd your car in stock trim first to see what it was pushing out before the intake exhaust mods were carried out. I do recall when I used to go on dyno days with mates and this dude had his 99' C43 AMG dyno for before and after intake exhaust mods and in stock trim he made 276bhp which was around 25hp down from stock figure but the car was 10 years old back in 2009 so still not a bad figure and after his mods he made around 290bhp which was a 14hp gain.

the interesting thing he said when he compared the stock run graph to that of mod run graph we noticed he had gained the 14hp at top end rpm but his low end torque curve wasn't flatish when compared to his stock dyno graph he lost some torque on low to mid range rpm but gained slightly more after 4500rpm. and the mechanic who carried out the dyno confirmed it was to do with his performance exhaust as his stock one was slightly restrictive which helped in developing back pressure for low to mid acceleration but performance less restrictive exhaust tend to loose out on low to mid performance due to not generating back pressure but gain at higher rpm when the exhausts gasses needs to be pushed out of the system quickly.

I personally think Lexus engineers spent months if not years to develop the stock intake/exhaust system to make it perform for low, mid and high rpm whilst keeping it quiet for when its needed but the Takeda + Exhaust combo does sound nice hopefully it wont have affected your low to mod range performance. but for 4.5 secs to 60 and 170mph with the fastest shifting gearbox in M mode when compared to competitors..all in stock trim, I personally would leave the car the way it is lol but that's me..

[stevet]

Good job you didn't dyno it first as I imagine it will now produce less power. But you afford to lose a few :)

[Stuno1]

Be interesting to compare it to a stock car. I don't thing it will be down on power. That is not my aim anyway but making the exhaust gasses flow more easily won't reduce bhp!

I have modded n/a v cars before so not expecting to lose bhp.

Noby - I think they spent a long time designing the stock system but not for sound or power. I think they had a bhp figure and designed around that. The stock system has pre cats/ cat and massive back boxes all which make exhaust gasses turbulent and reduce sound.

[noby76]

I think it all depends on luck with an intake /Exhaust mods when it comes to NA engines more so when its not accompanied with an ECU remap but not always the case as I heard some manufactures do their restricting from the ECU and just by remapping the ecu without doing any physical mods can unlock upto 20bhp as the intake and exhaust were already good to start with and only restriction was from the ECU side.

other manufactures might have an 'open' ECU which can map itself to some extent based on amount of intake air flow it detects coming in, fuel quality/RON being used, and header/exhaust system being used and if it detects an improvement on any of these factors with an aftermarket one, it then maps its self for better performance.

so all depends on where Lexus engineers have applied the ISF's restrictions the most. It could be the ECU side or the intake exhausts + cam profile side or both but we don't know for sure unless tests are carried out to know which side has the most restrictions. this engine was built with the help of Yamaha and I personally think the IS-F is at least a 500 bhp , 200mph car which has been muzzled to 420bhp, 170mph to start with and they then up it bit by bit as they release newer performacne models by tweaking intake design, exhaust design, maybe cams and most important ECU and valve timing mappings until the emission laws comes to bite them. but only a Lexus engineer who helped develop it can tell us were the most restrictions lie in the car.

cracking the ECU code and unlocking the rev limiter to red line at around 7600rpm instead of the 6600rpm will get the engine making 500+bhp easily. its a Yamaha engine after all so its bound to rev and operate reliably to at least 8000rpm but probably been muzzled to 6600rpm

[Stuno1]

Going on the us forum the ecu is not unlockable and with intake, headers and full exhaust system another 50bhp can be had so it seems the exhaust system is restrictive.

Stu

[Cable]

Hey dude, glad to see you've got a dual setup, though it looks like the secondary cats are still in place, these can be seen on the right hand side of the screen at about 17 seconds. Still, you should see a small gain...

As for saying it's going to lose power, that's the most ridiculous thing I've heard. Are you saying this from personal experience or just repeating the ye olde myth 'ooh, you'll lose back pressure and power'?

Back pressure is not a good thing, an ideal exhaust would have none. What it does need is to maintain gas velocity, which then, like syphoning, draws exhaust gas out of the cylinder, allowing a greater air/fuel mixture to be burnt on the next cycle. Too large a diameter exhaust, on a normally aspirated engine, will reduce gas velocity and low end power, but we know the ideal size for exhausts these days. For example, a 2L-2.5L engine would ideally want a 2.25inch-2.5inch exhaust. The ISF is a 5L V8, so dual 2.25inch-2.5 inch exhausts are perfect.

On a turbocharged car, it is almost a case of the larger diameter the better, as the exhaust wheel on the turbo requires the pressure difference to operate.

Neil

[Stuno1]

Cable - Is the box behind these cats a silencer then?

[Cable]

Yup, afraid so Stu. Link to a picture of a standard exhaust system vs an JoeZ

At the very top are the exhaust manifolds with the primary cats attached. Then the downpipes leading to the secondary cats. After that the exhaust joins into a single pipe with the resonator in the middle. Then the exhaust splits again leading to the two giant back boxes.

[Stuno1]

Ok so the resonator has been removed. Cheers for that.

If the second cats were removed would it stall pass mot?

Stu

[Peter P18]

Good question! I know it does on other cars (GTR), but not sure with the ISF?

Would it throw up any warning lights on the dash? Guess there may be only one way to find out! ;)

[Cable]

Yup, should still pass the MOT as the primary cats are still in place. The secondary ones will mostly be there to cover for markets that are particularly strict on emissions, such as Japan and Los Angeles.

As far as I'm aware, so please tell me if I'm wrong, there isn't any sensors located after the secondary cats, so no chance of a dash warning light being thrown up.

[Stuno1]

At the very least I imagine it would trip a sensor.

[Peter P18]

Guess I may opt to be the guinea pig! ;)

Guessing they can do a de-cat for the 2nd cats Stu? May cost a bit more, but worth it in my opinion.

That would be good to test back to back with yours on the dyno as well Stu. We can see how much difference it makes. :)