Supercharger Systems -4GEN Liberty/Legacy

[west_minist]

Tim,

How is the new impeller working out for you?

[Tradewind]

A bit of promotional effort for a change

[KiDo_Tuning]

Tim,

How is the new impeller working out for you?

4psi by 4000, pretty solid results

[Tradewind]

Tim,

How is the new impeller working out for you?

There are 2 forum members with it. I think both have posted about it.

Pudz and 3rspecb

3rspecb has a before and after perspective which is valuable to anyone considering the option.

Its all about a little more boost sooner in rpm range, more midrange torque and higher peak power

[PUDZ RSC3.0RB]

Tim,

How is the new impeller working out for you?

4psi by 4000, pretty solid results

Hey Matt from our last log can you recall my max boost ive forgotten.

Wouldn't mind getting max boost up to 9psi in prep for E85, so will consider changing s/c pulley to 58-59mm.

Tim, whats the smallest pulley size u can supply without voiding my warranty.

[west_minist]

Tim,

How is the new impeller working out for you?

4psi by 4000, pretty solid results

Makes for a nice smooth power delivery.

[PUDZ RSC3.0RB]

+1^ nice smooth power delivary for sure.

Tim
Yeah just exploring my options for a bit more power, im getting the pre-E85 checklist ticked off and am thinking of a smaller pulley to get maybe another
1.5psi of max boost . Is it the external front pulley on the s/c ?. What do u think and what is the process of upgrade?

[Tradewind]

Pulley sizes/pressures with standard cast impeller @ 7100rpm. If your tune exceeds this RPM limit then pressures will rise further.

61mm - 7.5psi
59.5mm - 8.5psi
58mm - 10psi

If a billet impeller is fitted the pressures may rise to 1psi extra on every pulley size.

The above pressures for mm diameter may vary from one installation to anothe, however they are the test/known results for a correctly functioning system.

To fit pulley, best to remove charger, remove existing pulley and fit new pulley, reinstall charger. Not a big job on a Liberty installation at all, slightly more involved IF watercooled charger is fitted



Cardoc got busy and fitted a clutch pulley at 54mm - highly unrecommended, he was able to do this due to having a clutch pulley type input shaft in the first instance. I dont know his final pressure etc, can ask him on his thread.

My speeds pulleys spreadsheet indicates that a 56mm pulley is entirely workable from a speed point of view, I have nothing of that size in stock tho (can machine a 58mm down), could bump peak pressure by up to 2.5psi. The FINAL word on going to 56 or smaller is - it will void your charger warranty totally, it is not tested by me for this application and therefore I cannot predict the outcome to the performance of the vehicle or the life of the charger.


********* I dont recommend any kit owner to go above 8psi without a complete upgrade of the exhaust to high flow specification from front to back. To go more than 8psi without complete exhaust upgrade is a waste of your time, my time and your money and system performance. Same goes for going above 8psi without charge cooling in some form or other

[west_minist]

Good info Tim.

The natural ve of the engine ends going to 7000rpm. You would just be straining the engine and also, you have to remember the little ponies on the rods

[KiDo_Tuning]

E85's natural cooling properties being sprayed directly into the intake manifold can increase engine load, so it lowers boost(more air cramped into same cylinder space is less air in inlet manifold) so considering the same Supercharger speed pushing against less pressure, it would be safe to assume better VE.

[PUDZ RSC3.0RB]

Tim
Cheers mate for posting all the above info, seems I have a fair bit to consider if I want more boost moving forward.
Thanx Matt & Ed, I was hoping u guys would chime in and express ur wealth of knowledge, as I definitely need this with whatever decision I make.

So ve = Volumetric Efficiency, thanx to google .

Hypothetically guys if upgrade as below:

United E85 fuel

Limit tune to 7100rpm - looking after those " stodgy rods "

Upgrade pulley to 58mm - giving max boost of 10psi, maybe a tad more with billet impellor in use.

Upgrade exhaust rear y-pipe to 2 1/4" x-force, this will then mean with raptor headers the whole system has been upgraded to 2.5" with TCP Quads.

Will consistent E85 fuel compensate for not having any cooling of the charged air with boost up to 10-10.5 psi. I don't think im keen to do intercooling of any complexity or is there another option.

Tim, Matt & Ed thanx again and I cant wait for ur replies.

Regards Grant

[west_minist]

My thoughts are, Intercool it. You will see greater power, especially when you pushing her.

E85 is nice and will allow you to meet your goals. But if your goals are high, compressing air heats it up. Your aim is to maximise the efficiency of the engine. Get more for less A cooler charge air mix with E85 = more power with the less boost.

Matt, do you suspect the heads may leak at this boost?

[Tradewind]

I personally have zero experience with E85, this fuel is not available in my area or for that matter most of Qld, meaning no opportunity to test and learn.

Temp reduction via water meth - useful and not overly complicated. Have lots of customers with V8 Fords using water meth and finding 30-40hp more

[west_minist]

E85's natural cooling properties being sprayed directly into the intake manifold can increase engine load, so it lowers boost(more air cramped into same cylinder space is less air in inlet manifold) so considering the same Supercharger speed pushing against less pressure, it would be safe to assume better VE.

I think its the same volume of air, maybe small % more in the intake, except at the point of the cylinder where you are now spraying more fuel. The cylinder can only hold so much volume of air. I wonder how much of a change it would be in respect to direct injection, allow a more denser air into the cylinder. But I see what you are saying. I can see a pressure drop at the point of spraying, thereby a small readable boost pressure in the intake. Would love to see the research on this in respect to flow analysis and thermodynamics

Like race gas, the ability to prevent knock is very important; raise boost to increase effective engine compression, add more fuel (its oxygenated) and some timing will yield the power we all know. e85 is like cheap oxygenated race gas.

[KiDo_Tuning]

My thoughts are, Intercool it. You will see greater power, especially when you pushing her.

E85 is nice and will allow you to meet your goals. But if your goals are high, compressing air heats it up. Your aim is to maximise the efficiency of the engine. Get more for less A cooler charge air mix with E85 = more power with the less boost.

Matt, do you suspect the heads may leak at this boost?

Robin is on 12psi with Water/Meth, no inter cooling and no heads issues. Just lower radiator temps to stop hotspots in heads. I really want to do a reverse flow head gasket for the H6 and chill exhaust valves first like the VQ35HR motor.

E85 is more consistent charge cooling. Chilled air is more dense thus more air in chamber before inlet valve shuts so higher g/rev despite airflow from impeller speed being same, so less boost. In theory, impellor and in turn the belt is not pushing against manifold pressure so is more eager to rev as well