Supercharged Phoenix is a go....

[jeffw]

Apparently not, just a crap design. Serves me right for buying ebay rubbish I suppose. Still going to be brutally fast as is and I will get the intercooler sorted out shortly.

[matt_gsxr]

Jeff,

2 steps forward, 1 back.

Regarding the intercooler, I have a similar one (as you know) and the problem I had was finding one that would fit.
There is a useful calculator here http://www.bellintercoolers.com/_pages/ ... Assem.html
The challenge will be finding an intercooler that works much better without being too big.

There is one thing you could think about changing though with regards heat rejection in your system.
The design that you are using has the dump valve after the intercooler. Further you have a recirculating valve.
As I see it (actually I read it) having the dump valve after the intercooler puts extra heat into the intercooler.
Also recirculating this pre-warmed air into the inlet further heats the intake air.


I haven't measured the pressure drop across my intercooler (although it is now on the to-do list), but I have precise measurements of the intake temperature and (in my case) the intercooler does a good job of cooling the intake (well below 40deg on the road, when I was getting 60degC without the intercooler).

Thanks for your regular updates, its interesting.

Matt

[jeffw]

Matt

At the moment I'm more interested in pressure loss than temps as the car hasn't been driven on the road yet. We are doing some pulley calculations at the moment because mine makes peak power lower than before since the mapping/cams optimisation. We have gained 20 wheel HP and 20 ft lbs during the mapping process at the same boost pressure. If we change the pulley we should gain 4-5psi at peak power and if I can make the intercooler more efficient (pressure wise) we may gain another 2-3psi there. With lower intake temps we may yet see the 300 wheel HP which is kinda my target.

[dopdog]

Interesting comment Matt, I thought the dump valve should be after the inter cooler and as close to the inlet as possible to reduce the pressure in the inlet manifold on over run? This is of interest to me as when I got my car it did have the dump valve before the inter cooler and I changed it over.

with regards to the inter cooler size again I was under the impression that bigger was better to get colder air in. How does the size reduce pressure?

lots of questions but always learning.

[jeffw]

There is one thing you could think about changing though with regards heat rejection in your system.
The design that you are using has the dump valve after the intercooler. Further you have a recirculating valve.
As I see it (actually I read it) having the dump valve after the intercooler puts extra heat into the intercooler.
Also recirculating this pre-warmed air into the inlet further heats the intake air.

Not sure I follow the logic to that. The air into the inlet will be warmer but will be cleared out well before the throttle is pressed again. With the car moving the air over the intercooler will be sufficient to cope with any slight heating effect from the warm(er) being introduced by the recirc valve.

The issue at the moment is we are looking at RR only temp and pressure figures and I know from experience that forced induction cars always perform better on the roads than on the rollers due to intake and intercooler temps being much lower sue to airflow.

[matt_gsxr]

The difference is in the heat capacity of the system 5kg of aluminium plus the intercooler pipes has quite a substantial thermal mass.
(interesting article here http://autospeed.com/cms/title_The-Fusi ... ticle.html )

Think of how it works like this:

The air flowing past the car gradually takes heat out of the intercooler
The compressed air flowing through the intake warms the intercooler
The hotter the intercooler gets the less well it can take heat out of the intake charge

It is an ongoing battle, anything you can do to put less heat into the intercooler is going to allow the air flowing past the car to get the intercooler to get to a lower temperature (which is good).


If the dump valve is before the intercooler then when your foot is off the accelerator the airflow past the car will be lowering the intercooler temperature and you will not be adding heat to the intercooler from the intake.
If the dump valve is after the intercooler then when your foot is off the accelerator the supercharger will still be pushing air through it, then the airflow past the car will be battling with the intake air and the intercooler temperature will not drop.


I can't claim that this is original thought, it is only what I have read. As you say the problem may well disappear on the road.

Matt

[jeffw]

Interestingly I've had a conversation with someone who knows...and long thin intercoolers are bad for pressure drops compared with high narrow (if you see what I mean). So we might need to revisit the packaging of the intercooler/cooling to recover the lost psi.

But I'm hopefully picking it up tomorrow and we can do the development work afterwards.

[matt_gsxr]

Interestingly I've had a conversation with someone who knows...and long thin intercoolers are bad for pressure drops compared with high narrow (if you see what I mean). So we might need to revisit the packaging of the intercooler/cooling to recover the lost psi.

That was also the message from the bell intercoolers site: (all units in 'merican)

depth width length cfm (1psi)
2.250 18.200 6.000 788
2.250 6.200 18.000 268

Where we have the "long thin" (i.e. second one).
Reducing the length and making it wider will help pressure drop, but it will also hurt its cooling efficiency.

[adithorp]

AIUI the width v height thing with intercoolers is to do with flow rates, effectng presure rather than actual presure drop, Remove air from the engine side (open inlet valves) and there has to be enough flow through the cooler for pressures to equalise quickly. Think of electrical resistors on parrallel (tall/narrow 'coller) v's resistors in series (short/wide 'cooler) .
By having the dump valve before the intercooler doesn't that cause negative flow in the 'cooler as the inlet side depresurises? Will that effect lag?

ps. what I know about forced induction could be writen on the back of a stamp.

[jeffw]

dump/recirc valve prior to the intercooler is not what the OEMs do.....which must be for a reason.