Toyosports exhaust manifold

[trooper99]

Just getting to know my 04 6 speed MR2, the car came with a used stainless Toyosports manifold.
It has the same upper O2 sensors as the standard one, but does away with the cats directly below this.
In fitting this sports manifold, I assume I'll also remove 2 O2 sensors along with the manifold cats?
What do I do with the sensors, assuming they are in the original manifold?
I've got lots of engine building experience, so any mechanical work isn't a problem....just a bit unsure about all these sensors on .modern' motors!  s:mrgreen: :mrgreen: s:mrgreen:

[Essex2Visuvesi]

If the manifold has the sensors aready installed then just swap out the manifold and connect up

I would highly recommend you get genuine gaskets from Toyota rather than the cheap ones off ebay

[trooper99]

Thats not the issue. The sports manifold has holes for the top 2 sensors, so I'll just fit the 2 from the standard one. This manifold is longer than standard, because it replaces the 2 cats directly below the standard part. I'm asking if the standard part has 2 more sensors fitted, below the upper pair?
I think I'll just have to unbolt the cover and have a look!
The Toyosports manifold has been supplied with gaskets so I'll re-use these, with a bit of exhaust paste added

[MartinC]

If you have got the correct manifold, it is a direct replacement for the OEM manifold and Precats, including the O2 sensors.

A UK spec MR2 only has 3 sensors, 2 in the manifold and one after the main CAT.  I think a MR-S has 2 sensors, 1 in the manifold and one after the main CAT.

[Essex2Visuvesi]

If you have got the correct manifold, it is a direct replacement for the OEM manifold and Precats, including the O2 sensors.

A UK spec MR2 only has 3 sensors, 2 in the manifold and one after the main CAT.  I think a MR-S has 2 sensors, 1 in the manifold and one after the main CAT.

Ah Mines the MR-S

[trooper99]

You are still missing the point! The Toyosports manifold is a performance upgrade. It replaces the 2 'pre-cats' directly below the standard manifold. It has 2 stainless steel pipes, in place of the standard pre-cats. I'm pretty sure the standard pre cats have an O2 sensor in each pipe.  I'm trying to find out if I just unplug the pre-cat sensors, or do I need to rewire them, to stop the warning lamps coming on?

[Ridds]

The toyosport has the same pre o2 sensor sockets as the standard manifold, when you swap the manifolds the sensor set up is the same with a sensor for each bank.

Sent from my GT-I9505 using Tapatalk

[trooper99]

Thats good news, thanks.   s:D s:D  
Where are the other O2 sensors fitted? I've been told there's 5 in total, I did assume 2 were fitted in the pre cats that are part of the standard exhaust manifold?
I'm planning to fit an induction kit, so far the K&N 57i-9002 looks good, along with this manifold: do I need to add anything else to get a power gain?
I will be looking at more mods in the future, don't want to be spending nearly £200 on an induction kit that will need replacing!

[Essex2Visuvesi]

Thats good news, thanks.   s:D s:D  
Where are the other O2 sensors fitted? I've been told there's 5 in total, I did assume 2 were fitted in the pre cats that are part of the standard exhaust manifold?
I'm planning to fit an induction kit, so far the K&N 57i-9002 looks good, along with this manifold: do I need to add anything else to get a power gain?
I will be looking at more mods in the future, don't want to be spending nearly £200 on an induction kit that will need replacing!

Having had a good read of the forums etc it seems a lot of people beleive Toyota did a good job with the stock system and there is little to be gained (other than noise) from changing it.
Seems adding a panel filter (K&N etc) is the best way forward

[lamcote]

There are only 3 O2 sensors, not 5, so the Toyo sport manifold is pretty much a straight swap.

My impression is that there isn't a lot to be gained from simple bolt on mods if you are staying with natural aspiration. However there is probably more to get from the exhaust than anywhere. I don't think an air filter does anything other than noise. I believe the 1zz filter is the same as the 2zz one so there's no restriction there. The Toyo sport will give a bit extra mid range, a PPE or Zero manifold would give a bit more (at significantly higher cost). A decent cat back exhaust will also make a few BHP. Beyond that you are looking at cams and or new ECU and custom tuning. All very expensive and still not much to gain. Having said that, if you get up towards 160-165bhp with all the above it will be a noticeably faster car.

[Carolyn]

If you have got the correct manifold, it is a direct replacement for the OEM manifold and Precats, including the O2 sensors.

A UK spec MR2 only has 3 sensors, 2 in the manifold and one after the main CAT.  I think a MR-S has 2 sensors, 1 in the manifold and one after the main CAT.

The MR S has two sensors in the manifold and none in the cat.

[MartinC]

If you have got the correct manifold, it is a direct replacement for the OEM manifold and Precats, including the O2 sensors.

A UK spec MR2 only has 3 sensors, 2 in the manifold and one after the main CAT.  I think a MR-S has 2 sensors, 1 in the manifold and one after the main CAT.

The MR S has two sensors in the manifold and none in the cat.

I stand corrected.    s:D s:D    Having never owned an MR-S, I knew they were only 2 sensors, but didn't know the configuration.

[Carolyn]

Just transfer the sensors from the old manifold to the new one.  They plug right in, no wiring needed.  If a light comes on, it's damage to a sensor.  They are a little delicate and don't like to be banged about.

[trooper99]

Thanks everyone, plenty to think about now!
I'm planning to swap the standard manifold & cats for my Toyosports decat manifold, along with 2 new sensors, and the K&N 57i kit: I've done similar work on my Mk1 MX5's and have seen a great improvement in the midrange power, which is just where I want gains, top end power isn't what I'm after   s:wink: :wink: s:wink:  
Toyosports claim a 10 BHP gain in midrange power, then maybe a few more horses from the induction kit, then add Iridium plugs which I always use, plus a stainless exhaust system, I should be getting a nice useful increase over standard   s:mrgreen: :mrgreen: s:mrgreen:

[1979scotte]

You wont get 10bhp on a 1zz with induction mods.
People how spend big money only get 30 or 40 bhp na.

[Anonymous]

Yep Scott's right does nothing without a map, however it does make it sound better so you think it's quicker.

For Na mods on a 1zz I don't think many people went further than me, and for an engine that had everything done not one standard part it only made an extra 50bhp

[trooper99]

It did seem a lot: I've modified dozens of engines over the years, some with better results than others!
The sound does make people believe they've increased output, ask all the chavs with deafening Corsas etc...
I would have thought the manifold minus the cats, a K&N or a BMC kit, good exhaust and Iridiums would give a 10 BHP gain, its only around a 7% increase. Depends on how good the standard parts are though. Some engines are already quite highly tuned as standard, seems like the 1zz is one   s:D s:D

[lamcote]

I may have asked you this before rbuckingham (apologies if I have) but is there a thread that details all the mods you did to get the extra 50bhp? Cheers

[Anonymous]

No but if you want to price it up look up the following parts

11.5:1 82mm wisco pistons
82mm sleeves fitted to block to suit pistons
Crower rods
Crower forged crank
3 stage lapped titanium valves
Titanium valve springs and collets
Crower stage 2 Na cams
Port and polished head.
Lightened flywheel and clutch.

Probably more but can't remember nowadays, but personally after the parts cost you might as well fit a 2zz. Unless your building your engine for later boost.

I am in the process of building a similar engine but low comp for some serious power, but house purchase kind of putting that on hold for a little bit.

[lamcote]

Wow, expensive! Did you hit 190 bhp? Was there decent power at low revs with the Stage 2 cams?
Did you do it all at once or in stages ie can you say what increase you got from each of the separate bits?

Sorry for the interrogation!

Also, to put it back on topic, what exhaust manifold did you have?

[trooper99]

I'll fit the manifold, decent exhaust, Induction kit and new spark plugs, from past experience I'd expect a 7-10 % gain: after that it will be a 2ZZ engine swap, no point in tuning the 1ZZ just to get to the 2ZZ starting point!
Now I need to find the correct Iridiums to fit my 'almost standard' engine...there's loads of 'correct' part numbers...  s:( s:(

[1979scotte]

Youll be lucky if you get 7bhp.

Save your money for a 2zz swap or add a turbo/supercharger.

Or not. Having a max tuned NA 1zz would be an achievment in itself. Not many about.

[monkeybrain1234]

Youll be lucky if you get 7bhp.

Save your money for a 2zz swap or add a turbo/supercharger.

Or not. Having a max tuned NA 1zz would be an achievment in itself. Not many about.

I second this comment. Not worth the outlay   s:mrgreen: :mrgreen: s:mrgreen:

[trooper99]

Thanks again for the info   s:D s:D  
One thing I've learned after 35 years rebuilding engines, is that its pretty easy to get the first 10% gain, and then almost impossible to get the next 10%, then the next 10%...  s:shock: :shock: s:shock:  
Replacing the induction side for a really good kit is a must, then a better exhaust. I've found gains from mildly porting the head inlet/exhaust ports, and where possible, I've opened up the throttle body as well.
I'll try all the above, hopefully it will result in a slight but noticeable gain in acceleration, and midrange throttle response: can't do much more as any further tampering may clash with the VVT!   s:mrgreen: :mrgreen: s:mrgreen:

[1979scotte]

Best of luck.
Anything is worth a try.
NA tunning on thses things is a PITA.