Thread: Bell Auto Services Hi-flow Intercooler. Any comments or reviews?

Originally Posted by Pickles2

I wouldn't even touch the exhaust.
Very minimal, if any, gains to be made there, as demonstrated by some of our friends on Def2 in the Uk, who have some pretty radical 170/180kw engines, but the exhaust is,.....standard.
I know, because this is where most of my expertise (if any) is, that on V8s, yes, a free flowing, big bore exhaust is important, particularly up in the rev range.
However, when ya talking Puma, compared to the rpm range of those V8s, Japmulti valve turbos etc, the Puma rarely gets above idle,....I mean it's basically all over by 4000rpm,....so I say, exhaust is not really important....it ain't gonna make a big difference.
Pickles.

Pickles, mate i disagree. The following opinion based on my research and experience is as follows in engines that are TUNED beyond factory spec.

There are many benefits to improving exhaust flow:
-better low down power and torque
- better fuel economy
- lower engine egts. Heat is the biggest silent engine killer

The back pressure myths have been completely busted in diesel engines. Diesels do not need any back pressure in the exhaust and any back pressure post turdo is considered to be a hindrance to power and torque. The puma is no different to any other diesel engine. In fact the bowler 90's run 3 inch exhauts (go on YouTube and try find a clip that highlights the exhaust note and you will hear that they are a free flowing exhaust).

Couriers will often remove catalytic converts to improve economy and engine longevity, any decent exhaut shop will tell you this fact.

I'm not saying a puma owner should spend money getting a 3 inch exhaust. Im saying that they should retain the standard diameter, remove the cat, block the egr and run a striaght pipe instead of the centre muffler

Close... Diesel exhausts must be matched to turbo and inlet...

Too big an exhaust and too small an inlet and turbo overspeed becomes a high potential.


Any decent exhaust shop will supply what you need not sell drain pipes for small engines.

Originally Posted by 1nando

Diesels do not need any back pressure in the exhaust and any back pressure post turdo is considered to be a hindrance to power and torque.

Heh. He said turdo.

I'm watching this. Interesting tech talk.

Have seen comment from people who should be pretty authoritative, like Pete Bell, urging caution about exhaust mods on TDCis to avoid "turdo" overspeed.

Thats the extent of any knowledge I have on the topic.... pretty bare cupboard.

I'm no einstein, and most of my 'go fast' knowledge is in the petrol camp, but my basic understanding of the engine as an 'air pump' stands true. You want to get more out of it (power) you need to put more in. If there is a flow restriction, you either can't get enough air in, or exhaust out, and power suffers. The biggest thing with performance tuning (the mechanical or controls side) is working out what is the limiting factor, and improving it enough to get the results. The old days of engine shopping via a parts book and choosing the thing with the biggest number or the most flames on it is over- engine tech has come a long way and I always try to put my faith in the gurus before thinking that I, as a mere mortal, know more than the 500 engineers and other great minds who built the thing before me. So if someone has done the calculations and it checks out, they are probably on a good thing.

Intercooler design is very interesting. Once again, my simple minded understanding needs to be taken on face value, but intercooler heat transfer is one side of the equation, but pressure drop across the core, end tank volume and design, tube/fin/turbulator density and thickness of the core all need to walk a balancing line between performance and true power gain. Likewise the ability of the IC to hold heat and dissipate it quickly is another concern. It's a heat sink as much as it is a heat transfer device. Hold heat during high boost periods and high IAT's then get rid of it when off throttle.

Hi

I'm not keen on exhaust mods, irrespective of their effectiveness, which seems to favour the not too much.

Mine is a family tourer, that I want legal and for long distance desert touring the last thing i want is a noisy exhaust droning all day. Don't want unwanted attention or defect notices either. For day to day use the BAS tunes either 150hp or 170 hp seems preferable.

Fair enough if you want up a weekend toy, go the noise, and I have a V8 County for just that.

Seems like no one has ordered these new BAS inter-coolers, i might be the first, on here anyway to place an order.

Clive

Funny!! And presumption at its highest.

The system I showed above - Decat, 2.5" Straight through box and rear resonator kept has Zero Drone, no noticeable exhaust note over stock at any rpm point, and has a notable improvement in throttle response and drive ability.

Good system design is not a compromise.

And don't assume that others haven't already ordered said IC

Originally Posted by 1nando

Pickles, mate i disagree. The following opinion based on my research and experience is as follows in engines that are TUNED beyond factory spec...........


- lower engine egts. Heat is the biggest silent engine killer............

EGT's do kill engines quickly and many are misled as to what they are looking at.
Seems to be the popular belief that bigger exhausts = lower EGT's.

EGT's are a direct function of the combustion process ie ECU Tune.
Specifically fuel and air will determine your EGT not the size of your exhaust.

Typically larger exhaust provides more volume for exhaust gases to exit and expand therfore cooler temps at the probe only, not in the combustion chamber where the EGT is generated.
Folks are seeing probe manipulation not actual gas temp in combustion chamber changes.

While faster spool for a turbo may see a better initial or intermediate air flow/pressure for a corresponding rev range, which may give few degress cooler momentarily, it is generally a performance benefit not an EGT reduction. Sustained measurable reductions in EGT from exhaust size increse is probe manipulation only.