Plenum Spacer

[DoubleDeuce1973]

Ok guys and gals,

 

Decided that a Plenum Spacer needs to be on my shopping list.

 

Where do I get one and which one should I be getting. Understand there is thermo, copper and whatever else. I just want to get set up for a re map in the future and can live with 11 hp rather than 14 if it will make life cheaper and easier.

[HassanZ]

If someone organises a group buy, I may be interested in purchasing one with you

[DoubleDeuce1973]

If someone organises a group buy, I may be interested in purchasing one with you

 

GROUP BUY!!!!!!

[HaydnH]

Lots of competition around, Motordyne seem to be the favourite brand with Tarmac, zmanalex and Abbey M/S all selling them (probably others to, just off the top of my head). I think horsham dev sell 1 they've made themselves which may be a cheaper option.

 

Although, if you're going for an uprev after fitting you mods it may be easier to get the parts from Abbey who can fit and uprev all in 1 go if you're down south.

[Aust350z]

+1 on the place doing the remap doing the spacer install as well. You can get dyno before and after easily then

 

Where do I get one and which one should I be getting. Understand there is thermo, copper and whatever else.

 

Go 5/16" over 1/2" as you can retain your stock strut bar.

 

Forget the basic get the iso thermal if your going to the trouble of getting a remap as well.

 

Iso thermal requires a coolant valve to be installed so you can open and close it in cold/freezing weather. This means cutting one of your lines to install it (or you can choose not to install it at all).

 

The copper version works like the iso thermal but instead of needing to cut your coolant line it replaces the need for the valve completely and adds a copper spacer up near the throttle body.

 

If it snows in your area then you must get the copper - no question.

 

I bought the copper as it gives you the option to completely remove and return the car to stock if you wish. For a little bit you also don't have the hassle of needing to open and close the valve on the iso thermal version - kinda install and forget which I liked.

 

Hope this helps.

[cmck13]

Have a good search on this site we have discussed this subject inside out and the conclusions in general were that there was little or no real gain with the thermal spacers in this country, especially if you have the one with the valve and forget to turn it back on.

Horsham on this site supply their own make of this, because after all are they are only an aluminium spacer when all's said and done, and they were doing a group type buy a few weeks ago, Jez would probably do you a good deal without any need for a group buy.

I have one and they do make a difference in air volume , one of the main ingredients in improved performance.

[Tricky-Ricky]

Always makes me chuckle when all the attributes of plenum spacers and "thermal" gaskets etc are discussed, it seems to me that there are an awful Lot of misconception's about,

the first being that as std the front two cylinders run weak, utter tosh! think about it, the std map is optimised to give a stoic AFR throughout the closed loop areas, and a safe (in fact too rich) AFR in open loop, so in fact if the std plenum is actually causing reduced airflow to the front cylinders, the actual result will be a slightly richer mix to these cylinders.

 

The next being iso thermal gaskets, now admittedly if you fit one that actually works, the best place to fit it would be the plenum base gasket, and not the spacer gasket or throttle body, as this situation would stand the most chance of preventing direct heat transfer, however because of the plenum's design and situation, its still going to receive more than its fair share of radiated heat from the heads etc,

And as for using copper gaskets, this will actually transfer heat faster and more efficiently.

Finally there is the throttle body water feed disable, the fact that there is little evidence that backs up its current use on later ECU controlled motors, other than a possible emission's criteria, it was developed initially as an aid to starting and running on carburettor engines, and helped prevent icing, but as the modern throttle body sees no fuel, its very unlikely to ice up at cold start, also if you think about it, the water is cold at start up!

 

Getting plenty of cold air into the engine is the key to getting more power out, but unless you can also achieve more fuel to match, its a complete waste of time, and given the 350Zs ability to adjust its closed loop fueling, the use of any airflow enhancing devices is wasted without a remap to account for these improvements.

[Toon Chris]

The closed loop system will work on an average over the cylinders that a lambda is looking at. This means the air/fuel ration can differ slightly across whatever bank(s) the lambda(s) is/are 'sniffing'.

For the Z, matching up the air/fuel ration more evenly across all cylinders - or in particular making sure that the more air-starved front cylinders are getting a fair share - will make the engine more efficient with each cylinder getting the best mixture that the ecu map allows for, and so hopefully more powerful. The ecu won't make any adverse adjustments as the closed loop system still sees exactly the same parameters.

Getting a better fuel/air ratio where it is currently inefficient will always give better power. Getting more air into slightly starved front cylinders will do this for you. Of course whether it's a noticeable amount is another thing and the remap is always going to be the way to go to get the best from an engine that is working efficiently. However, IMO it does make a small difference even without a mapping.

Regarding thermal gaskets, anything that stops part of your engine dealing with air volume getting hot is great, but as T-R says, you might stop heat-soak for a little while but its a hot area of the engine and you are n a losing battle. If it costs the same money then stick on a thermal gasket, but if it costs more IMO don't bother.

T-R, yes heated throttle body is for emission control to warm it up faster in cold weather. I agree with you that disabling it won't do anything much for power, and certainly nothing noticeable to the driver. A much, much more useful idea is to get a decent cold air feed in the first place.

[Tricky-Ricky]

While in theory i agree with what your saying IMO even though the Lambda feedback may slightly adjust, should that bank see better airflow to one or more cylinders from the fitting of the plenum spacer, because the adjustment is accomplished by changing the injector duty cycle/duration across all three cylinders, it actually negates the benefit, as although the front cylinder is seeing more airflow, the other two are almost the same, and so the resulting adjustment is averaged out, just like before the addition of a spacer etc, so IMO the difference will be negligible,and imperceivable.

 

I know that through Osiris remapping software its possible to richen or weaken individual cylinders, so i would suspect that Nissan have already tweaked the front two cylinders to take the this reduced airflow into account, so adding a spacer will compound this.

[M13KYF]

it will will help with mid range torque but not top end BHP.

[Wasso]

Just get a basic plenum spacer. There no requirement in the uk for the others.

[Tricky-Ricky]

Please don't get the idea from my little rant that i don't think the addition of a plenum spacer is a worthwhile mod along with a remap, because it is, its just the other misconceptions that i was trying to illustrate.

[M13KYF]

Please don't get the idea from my little rant that i don't think the addition of a plenum spacer is a worthwhile mod along with a remap, because it is, its just the other misconceptions that i was trying to illustrate.

 

 

thats why I posted, it did look like that, it made out that there was no need for a plenum spacer so clarification I thought was helpful

[Tricky-Ricky]

Please don't get the idea from my little rant that i don't think the addition of a plenum spacer is a worthwhile mod along with a remap, because it is, its just the other misconceptions that i was trying to illustrate.

 

 

thats why I posted, it did look like that, it made out that there was no need for a plenum spacer so clarification I thought was helpful

 

 

I realised that and had a re read of my posts, hence my statement, it was more the weak mixture on the front cylinders as std and the thermal stuff that i was disputing, fitting a spacer on its own will result in improved airflow no doubt about it, and because of that, a resulting increase in torque, but it does need a remap to make the most of it, sorry for the confusion