I've just fitted bigger smic's, the original air ducts will fit back on. Will they help with the flow of air or restrict it as obviously they're much smaller? Should I leave them off? Thanks.

Correctly fitting ducts are an important (and often overlooked) part of getting the most out of larger than stock

intercoolers. Air will follow the path of least resistance and it is important to direct (force) the air over as large a

part of the intercooler as possible. This is particularly the case as the intercoolers sit in front of what is essentially

a box with a NACA duct at the bottom as the only exist for the air after it has passed through the intercooler.

 

I remember reading an article (which I now can't find) that the difference in cooling efficiency for intercoolers on a

Z32 with and without full ducting was in the order of 30%.

 

I used Stillen ducts for the HKS intercoolers which covered the entire face. I also needed to modify the indicator

housings to clear the ducting (the rear bulb holder). The picture shows a full face Stillen duct and intercoolers.

 

Ok so better to run with the stock ducts for now than nothing. I'll have to upgrade the ducts later in the year. Thanks Andrew.

I run my pace smlc’s without ducts Tom, never been a problem for the last 5 years or so.

If some fell in my lap I would then have a go at fitting them but I’m not losing sleep over not having anything there.

 

 

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I run my pace smlc’s without ducts Tom, never been a problem for the last 5 years or so.

If some fell in my lap I would then have a go at fitting them but I’m not losing sleep over not having anything there.

 

 

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They would not generally cause a “problem” as such, but without the ducts, a large majority of the air may find its way around the outside of the matrix as apposed to flowing through it, resulting in raised intake temps and ultimately less power. I’d say that an unducted larger cooler has little or no benefit over a stock setup with the ducts.

 

I do wonder how much R&D goes into these ducts for the larger coolers though as they all have a significant divergence in the duct immediately prior to the matrix (obviously to clear everything in the area). This has an effect of slowing the airflow velocity down and increasing the pressure at the face of the cooler; I wonder how this compares to the calculations from the OEM with regards to the amount of flow for both intake and cooling air as the characteristics are altered. Also, the negative pressure created by the NACA at the exhaust air side would’ve been tuned by Nissan to produce a specific flow rate at a given pressure, which has now been altered. Getting the air out is just as important as getting the air in but I’ve seen little in the way of research into this side of the coolers.

 

Or maybe I over think things!

I’ve just stumbled across this post searching for something else and it reminded me of another I read a few days ago which others may enjoy. Not too much on ducting but some other interesting “facts”.

 

https://www.zdriver.com/forums/300zx-z32-tech-tips-273/intercooler-writeup-long-19694/

 

Anyway, back to what I was looking for.

When I bought my Ashspec Massives I bought the ducts with them as well as it's a bit of a no brainier. I would not use any ducts that would restrict the air flow though. They are only needed if you want the full potential out of the new ICs but then again why would you not as it's just a slight waste of money then.

I ended up buying ducts from Canada, had to modify them slightly to get the bumper on but better than nothing

imo, ducting will always be better, even if it is stock ducting and doesnt cover the full intercooler area, as long as the ducting does cover the area closest to the entry and exit pipes of the intercooler, e.g. the area which would be flowing air with the path of least resistance.

 

The non ducted part will be slightly warmer, therefore the air will be slightly warmer, so the actual exit temperature will be an average value based on temperature and volume of air passed through the colder fins, and volume/temperature through the warmer fins.

I’ve just stumbled across this post searching for something else and it reminded me of another I read a few days ago which others may enjoy. Not too much on ducting but some other interesting “facts”.

 

https://www.zdriver.com/forums/300zx-z32-tech-tips-273/intercooler-writeup-long-19694/

 

Anyway, back to what I was looking for.

 

I used that write up when I chose what intercoolers to go for, thus having Greddy.

“I believe that GReddy's did the best on the outlet temperature tests because the car used during these tests had a stock fascia.”

 

That write up is nearly 15 years out of date though and many more superior coolers are available. It would be interesting (and quite valuable data) to re run this test with the current available line up.

 

I think that all these super, massive, cram it in and chop your indicators in half type intercoolers are overhyped and under designed! A sensible height with no mods required, utilising a deeper core, properly ducted and with 2.5” inlet/outlet is the way forward, the big names are just in dimension wars at the moment!

That write up is nearly 15 years out of date though and many more superior coolers are available.

 

For example?

 

I think that all these super, massive, cram it in and chop your indicators in half type intercoolers are overhyped and under designed! A sensible height with no mods required, utilising a deeper core, properly ducted and with 2.5” inlet/outlet is the way forward, the big names are just in dimension wars at the moment!

 

I guess that's why SZ have invested and made their own version of the AshSpec Massives then?

 

https://www.specialtyz.com/sz-smics.html

 

http://www.ashspecz.com/shop/prodInfo2.php?prodID=17

For example?

You’ve just given one below. The Ashspec massives are now on version 3, the Z1 BA have changed significantly, most if not all of the coolers in that test are no longer available. Maybe “superior” coolers was the wrong word but certainly the companies selling them will have you believe that.

 

 

 

I guess that's why SZ have invested and made their own version of the AshSpec Massives then?

 

https://www.specialtyz.com/sz-smics.html

 

http://www.ashspecz.com/shop/prodInfo2.php?prodID=17

 

That just proves my point, they’ve taken the dimensions of the largest available cores and just made them bigger!

 

Like many of the other big sellers, these companies have realised that Ash is too unreliable to sell his products and so it makes sense to develop their own and keep their stake in the market share. 99% of people buying these coolers are on a numbers game for the largest cores so if they made them a sensible size, they won’t sell as well.

 

If they did some proper testing and comparisons, it would no doubt help them sell a few more but for the time and money to stage a reliable and accurate test like that, it just isn’t worth it. Of the 99% that just want the biggest available, only 15% of those will bother to read and digest the test results anyway!

 

Take this intercoolers package for example: https://f2rq3.app.goo.gl?link=https://app.alibaba.com/dynamiclink?touchId%3D60699355558%26type%3Dproduct%26schema%3Denalibaba%253A%252F%252Fdetail%253Fid%253D60699355558%2526ck%253Dshare_detail%26ck%3Dshare_detail%26shareScene%3Dbuyer&apn=com.alibaba.intl.android.apps.poseidon&ibi=com.alibaba.sourcing&isi=503451073&amv=69

 

They’re £175 plus £95 shipping, 2.5” inlets/outlets and the same core dimensions as the massives. I have heard that the company producing the massives didn’t get paid after he switched manufacturers and that they produced their own version without the embossed logo. Either way, I wonder how well these perform in comparison the big brands, I wouldn’t be surprised if these particular components are all produced using the same core material!

Edited October 2, 20196 yr by Joely P

My car has the generic Chinese ones, often branded as Godspeed, Japspeed etc. They are genuinely massive. We found that the stock intercoolers weren’t coping that well at 16psi, a few pulls and the heat soak was evident. I haven’t had chance to retest with the new coolers, I doubt they are significantly better than stock, however they have got to better than 30 year old stock coolers with 30 years of use and abuse. I have butchered the stock ducting and opened the “exhaust” area to allow that heated air to exit as well.

 

I’d update the results but next time the car is dyno’d there will be too many altered variables to be a fair test.

Take this intercoolers package for example: https://f2rq3.app.goo.gl?link=https://app.alibaba.com/dynamiclink?touchId%3D60699355558%26type%3Dproduct%26schema%3Denalibaba%253A%252F%252Fdetail%253Fid%253D60699355558%2526ck%253Dshare_detail%26ck%3Dshare_detail%26shareScene%3Dbuyer&apn=com.alibaba.intl.android.apps.poseidon&ibi=com.alibaba.sourcing&isi=503451073&amv=69

 

They’re £175 plus £95 shipping, 2.5” inlets/outlets and the same core dimensions as the massives. I have heard that the company producing the massives didn’t get paid after he switched manufacturers and that they produced their own version without the embossed logo. Either way, I wonder how well these perform in comparison the big brands, I wouldn’t be surprised if these particular components are all produced using the same core material!

 

 

They are different core sizes.

They are different core sizes.

 

You’re right! There are so many on Alibaba that I didn’t want to scroll through and many of them don’t document the core size. The pair I was quoted for matched the core size of the Ashspec V2. My point remains though.

What point are you trying to make here? I'm not defending Ash's business practices here, but I do respect

his technical competence. Unlike nearly all the "competitors" making similar "designs" (read copies in most

cases of his products), he did back up his designs with extensive testing and published them on TT.net.

and opened the “exhaust” area to allow that heated air to exit as well.

 

I was reading about the removal of the canister behind one of the IC to allow a better flow from front to rear. I must say I’m tempted to do this but not sure if I want to pull too many OEM parts off the car. What else have you done Stephen?

Might as well get started on AMS copied 2.5 inch piping. Great idea to copy a design and sell it for less however feedback from some people is the fitment is crap. I trust Ash Powers has put the R&D time and money into the design and that is why I got the massives. There ain't no knowing what manufacturing errors/tolerance laziness exists inside an IC. People are welcome to go with whatever ICs you wish to make your wallet happy just dont moan when your Dyno figures don't reflect what you expect. It goes for alot of parts really.

Personally i like the BA,s from Z1 ,For the money along with the pipe kit they are excellent value.

What point are you trying to make here? I'm not defending Ash's business practices here, but I do respect

his technical competence. Unlike nearly all the "competitors" making similar "designs" (read copies in most

cases of his products), he did back up his designs with extensive testing and published them on TT.net.

 

That I don’t believe there is much consideration for the optimum efficiency of the core flow properties anymore and the main focus is on a dimensions numbers game! I feel as though they all probably use the same standard core specification.

Personally i like the BA,s from Z1 ,For the money along with the pipe kit they are excellent value.

 

The original Z1 BA core dimensions were bob on if you ask me. They weren’t so tall that the top of the core barely saw any airflow in most applications and the indicator clusters didn’t need butchering, all they needed was to make the cores .5-1” thicker and utilise 2.5” inlet/outlet and that would’ve been a design worth developing/tuning for optimum airflows.

I was reading about the removal of the canister behind one of the IC to allow a better flow from front to rear. I must say I’m tempted to do this but not sure if I want to pull too many OEM parts off the car. What else have you done Stephen?

 

In what respect? My cars a long way from factory.

In what respect? My cars a long way from factory.

 

To open “the “exhaust” area to allow that heated air to exit as well.” Maybe I be got the wrong end of the stick but I thought you were referring to clearing space behind the IC to allow forced air to freely flow through the IC.

To open “the “exhaust” area to allow that heated air to exit as well.” Maybe I be got the wrong end of the stick but I thought you were referring to clearing space behind the IC to allow forced air to freely flow through the IC.

 

that's the purpose of these vents, NLA from Silvia Engineering

To open “the “exhaust” area to allow that heated air to exit as well.” Maybe I be got the wrong end of the stick but I thought you were referring to clearing space behind the IC to allow forced air to freely flow through the IC.

 

Yeah. I have done what your thinking. So I’ve deleted the Carbon Canister, repacked and relocated the radiator expansion tank, then cut the arch liners to allow the air to pass quickly away from the cooler. I did toy with replacing the washer bottle but in the end I decided that there was a sufficiently clear pathway round it.

Once you have removed the CC, there is plenty of space behind the IC with the stock overflow tank in place.