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4 Simple Boost Questions For R33


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Four simple questions about boosting a RB25DET from a R33.

1, What is standard boost? 7psi

2, What is the maximum boost that the stock turbos can handle? (or what boost level should i keep it under) The answer to this question would vary from car to car. I had mine tuned on 12.5psi and it ran that for about 2 years without a problem, took it off due to upgrading the turbo. I have seen other mates car's turbo letting go at 10psi or slightly higher. Condition of the turbo matters as well but best not to go over 12psi (well thats what my tuner recommended at that time)

3, If I have a pod filter, slightly bigger SMIC and turbo back exhaust with sports catalyser, what boost will it naturally creap up to? 8psi'ish

4, Whats the typical bog standard R33 rwKw figure and what might it be with the mods from question 3? Depends on the dyno you are getting it done. Some dyno's are "happier" then others. So expect somewhere from 160-180rwkw. Again telling from my experience with exhaust, pod and coilpacks on 7psi my car made 180rwkw. Depends on the condition of the motor etc

Thanks all

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That mesh in the afm is actually there for a reason. I believe its to straighten out airflow before it reaches the resistor wire so it can take an accurate reading. I dont think its really necessary to remove it when it hasnt actually been proven to be a restriction.

Plenty of people have made alot more power with it still intact.

In 'Four Stroke Performance Tuning' by A Graham Bell, it says you can get up to a 2% power increase by removing the mesh.

I agree it is there to smooth out the flow but my thinking is that I have a symmetrical POD filter on the end anyway. The flow is already entering the mouth of the AFM in a uniform/equal way, rather than the OEM airbox where it get sucked in a round a kind of bend and to one side.

So I reckon with a POD you don't need it and my car runs good.:thumbsup:

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Nothing wrong with a nice induction sound - it keeps things lively and entertaining.

As for running a side-mount with 12 psi on the stock turbo I don't think that is very good advice at all, especially in a hot country.

Only a fool would buy an R34 SMIC especially if they are gonna get a bigger turbo later.

I agree with the induction note, nothing wrong with a little audio, tho for the next points, 1, don't live in a hot country and in the interests of good throttle response, keeping things as close to Nissan spec as possible should make for comfortable driving. I havent really felt power loss yet and that includes while drifting, so i think the humble SMIC has some undeserved flack. Nothing wrong with big FMIC for high power applications, but this aint that.

and 2, not planning to get a bigger turbo at this stage, so a $40 intercooler upgrade sounds just about right to me.

Heres a related question, is it a waste of money to hook up a FCD with only exhaust and inlet modifications, and boost of around 7-9psi? I remember getting fuel cut year ago on my CA18 Silvia and that sucked.

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After I installed an aftermarket ecu and ran 14psi on the standard turbo the r34 sidemount would last about 3 0-80 floor its before it was too hot to touch. Then it turns into an interheater :whistling: I got a frountmount to my door for $220 and a pipe kit for $240. The worst heat I have felt is, the in tank gets a little warm, the core barely gets warm and the out tank stays cold. So for $420 on top of your sidemount upgrade you could have something that actually works well. Oh and fitting was a couple of hours cutting and welding in the shed.

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After I installed an aftermarket ecu and ran 14psi on the standard turbo the r34 sidemount would last about 3 0-80 floor its before it was too hot to touch. Then it turns into an interheater :whistling: I got a frountmount to my door for $220 and a pipe kit for $240. The worst heat I have felt is, the in tank gets a little warm, the core barely gets warm and the out tank stays cold. So for $420 on top of your sidemount upgrade you could have something that actually works well. Oh and fitting was a couple of hours cutting and welding in the shed.

This

The amount of cheap yet still decent coolers out there means you can pick up a kit for less then $500

Think of it not as a performance mod (Cause you wont feel much) but more as insurance. Heat is bad, you dont want that

And I'd be more inclined to say expect 130rwkw-180rwkw.

Depending on how harsh your ECU's R&R is will make all the difference. I only made 140rwkw with my stock computer, 8psi, FMIC, Nismo Fuel Pump, Pod filter, 3" Exhaust

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In 'Four Stroke Performance Tuning' by A Graham Bell, it says you can get up to a 2% power increase by removing the mesh.

I agree it is there to smooth out the flow but my thinking is that I have a symmetrical POD filter on the end anyway. The flow is already entering the mouth of the AFM in a uniform/equal way, rather than the OEM airbox where it get sucked in a round a kind of bend and to one side.

So I reckon with a POD you don't need it and my car runs good.:thumbsup:

Fair enough. So long as you are happy with your setup, thats what matters.

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2% oh yeah right, so thats 6 rwkw of extra throbbing uncontrollable power in 300.

Doesn't sound much but all adds up and it's a 2% which takes 10 mins and is free.

Peeps spends $$ doing head porting and polishing for just a % or two.

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Insurance for sure. I would watch my knock levels get unacceptable after a few short bursts with the sidemount. The engine gets cold air now when before it wasn't. Also the bigger core is less restrictive.The boost gauge showed 2 more psi at the manifold after the swap. As stated not so much of a gain but stacks more safety. And for what its worth it looks better :closedeyes:

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That mesh in the afm is actually there for a reason. I believe its to straighten out airflow before it reaches the resistor wire so it can take an accurate reading. I dont think its really necessary to remove it when it hasnt actually been proven to be a restriction.

Plenty of people have made alot more power with it still intact.

yep, if the mesh is removed i generally wont touch em.... especially if its gonna make decent power as it increases the reversion through the maf.... they are designed as a slight damper.

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yep, if the mesh is removed i generally wont touch em.... especially if its gonna make decent power as it increases the reversion through the maf.... they are designed as a slight damper.

Do you have an evidence to support reversion?

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Insurance for sure. I would watch my knock levels get unacceptable after a few short bursts with the sidemount. The engine gets cold air now when before it wasn't. Also the bigger core is less restrictive.The boost gauge showed 2 more psi at the manifold after the swap. As stated not so much of a gain but stacks more safety. And for what its worth it looks better :closedeyes:

Those side mounts are tiny, i remember the difference when i got a FMIC , it was flowing so much that the boost creeped up from 11 to 15psi, ended up having some overboosting problems,( another story)

Edited by SliverS2
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I remember reading that the R34 smic is good for flowing around 200rwkw. And I replaced my side mount item with the 34 one because it is slightly larger and had done a few mods to my 33. Its definitely a cheap $50 odd option, but with the mods you are going for its really probably going to be at its limit. I have just bought one of the cooling pro black stealth fmic, and i feel that its well worth it considering it was only $500 brand new. I know from reading on here that my mods will give me roughly 180-200rwkw and i just dont think the 34 smic will be optimal. Plus i plan on a hi flow turbo, upgraded fuel pump and injectors in the future, and the 34 smic definitely wont be enough for that. thumbsup.gif

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I'm not sure what that proves or how it means a car will have problems with the mesh removed.

also.... how is soot going to get there? The only thing before that is the pod, so unless your filter isnt doing its job or is an oiled filter depositing small amounts of oil.... I dont see it happening

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also.... how is soot going to get there? The only thing before that is the pod, so unless your filter isnt doing its job or is an oiled filter depositing small amounts of oil.... I dont see it happening

Well I don't think any filter is 100% effective so could get sucked in?

Also if you have the re-circ valve and OEM blow-by set up then that all that vents very close to the AFM so you could get some air and crap going backwards through it under the right conditions.

Still I don't see how the mesh is gonna stop it. If the mesh is gonna stop that then it would be a massive impedance to airflow in the other direction also.

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I would imagine that cutting that mesh is similar to decatting your cat, its a form of restriction on the exhaust for sure, so the same might apply to the afm....

The mesh would help spread the air out more in uniform pattern compared to having no mesh maybe..but the mesh closest to the turbo could be cut out without affecting that air spread

That would help to make the intake side less restrictive but also add things like a new smooth pipe between turbo and afm and good pod, air box, and cold feed, just like the exhaust has a smooth dump pipe and a decatt is better, same apply to intake???

what do you think?

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mythbusters ahoy today

removing the mesh from the airflow meter achieves nothing other than increase the change of reversion

the mesh breaks up the airflow pattern thus avoiding reversion

much like the accordian style pipework does the same job to the compressor wheel

remove the mesh you get reversion, replace the std accordian pipework for perfectly straight 3" steel and you get reversion

the standard r34 SMIC is not suitable for 200rwkw

its a poor core, its too small and it mounted in the wrong spot

after 1 or 2 runs the core is heatsoaked and useless

a front mounted larger core is critical for any decent power level

yes a 34 SMIC will make a single 200rwkw dyno pass

but do the same dyno runs repeatedly with a temperature probe on the core and intake pipework

i bet you see 70+deg intake temp. a FMIC in the same conditions is stone cold at the outlet pipework

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Im not sure what reversion is about.... what happens on cars that have no filter no afm and no pipe, do they get reversion too?

Edited by SliverS2
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