The V8 Owners Forum -

Gotcha.
Can you also program it to open when you close the throttle to act as a dump valve - to save the compressor from surge?

As far as I know mate yes
Dale is my ecu guru and supplied the valve so I'll have to check with him

A little update,
The car went to Dales on the 9th of November for final mapping (we hoped),
Due to covid the car had to be left there and i returned home,
after a day of rewiring the boost valve, idle valve, water injection etc, Dale started setting the ecu up to control the extra functions,
Mapping started and everything seemed to be going ok until boost mapping started, and yet again we were plaugued with issues,
The water injection system was killing power as soon as activated, need to order even smaller jets now,
And the charger was very slow to build boost low down then once it started making boost struggled to hit 15psi, which was strange as the charger is geared for around 30psi,
And suspected clutch slip smell of burning clutch, FFS thats a brand new Mcleod RST twin plate,
car retuned home without the magic numbers we were aiming for, we made 461bhp at the fly though, wheel hp was low though,
on investigation it seems the electronic valve is leaking boost and quite a lot, so currently Dale is working on having the spare boost valve sleaved and a better sealing butterfly made and fitted,
While Allan and myself have got a back up plan which i will be trying out as soon as the parts arrive,
Its a mechanical boost valve which is set to 20psi and is coupled up with the vac operated bullet valve from procharger,
And the burning clutch was rear brakes binding, as after a 10 mile drive off boost you could smell it, And the rear wheels were covered in brake dust was just a linkage adjustment on the pedal to ABS pump setup,
One way or another it needs to work this time round as not much fun looking at a car sat in a garage each year

If you're injecting only water....you will only ever want pretty small amounts. Although depending what setup you use, it's pretty easy to PWM the pump to give some user control over flow for same jet sizes.

If you add methanol, or run only methanol, it's pretty idiot proof in terms of injecting too much.

And as I'm sure I've said before....screw any ideas about trying to bleed off boost. It's a bad way to do things, or try and do them.

Not sure I understand:

we made 461bhp at the fly though, wheel hp was low though,

Dyno measures wheel torque/HP - then estimates flywheel power! If wheel measured power is low - then actual power is low!

What was the actual wheel measured HP?

Are you getting supercharger belt slip?
If the marketing sheet says - UPTO 30psi for the charger then ignore that!
Calculating the actual boost the supercharger will make on YOUR engine is very difficult.

SuperV8 wrote: ↑

Sat Dec 26, 2020 5:13 pm

Not sure I understand:

we made 461bhp at the fly though, wheel hp was low though,

Dyno measures wheel torque/HP - then estimates flywheel power! If wheel measured power is low - then actual power is low!

What was the actual wheel measured HP?

Are you getting supercharger belt slip?
If the marketing sheet says - UPTO 30psi for the charger then ignore that!
Calculating the actual boost the supercharger will make on YOUR engine is very difficult.

How much boost it makes, will massively depend how much air the engine can consume. The more restrictive the engine, the more boost it will make for any particular impeller speed....and boost is not the goal.

There's a lot going on with this engine but fundamentally it's not hitting the figures it should.

As Stevie rightly says with it being a supercharged engine "boost is not the goal", in fact quite the opposite.

So looking at what we know this is what I see. We know the NA baseline BHP is just shy of 300bhp, we know we are currently getting 460bhp at the flywheel.

As for the charger, well if I may lets assume that it is putting out 32psi (acknowledging boost is a measure of restriction, but stay with me). Dale reported a max of 15psi so lets work it backwards.

32 - 15 = 17

So 17psi is doing something somewhere. Most likely a combination of getting into the engine and leaking out past the boost valve. We can calculate how much the engine is useing on the basis that there is a direct correlation between psi and increases in bhp. Roughly speaking for every psi of boost you get 6.5% more power over baseline, not cummulative.

So the 17psi that we can't account for is not all going into the engine, if it were we would be seeing over 600bhp at the flywheel but still only showing 15psi on the gauge. Now we know that we are making 460bhp, or 160bhp over baseline so my estimate is that a maximum of 8-9psi is being used by the engine. The other 8-9psi is leaking past the boost control valve leaving 15psi showing as the restriction in the engine. Now if we stop the leak (by removing the control valve) there is no guarantee that we will see any more power. We may just see the boost gauge climb to 23psi with no additional power, although that is somewhat unlikely.

My assumption is that the inlet system isnt up to the job and the restrictions inherent in it are hurting BHP.

I've been discussing with Tony the need for a new inlet system for some time and we will be looking at that in the near future. In the meantime we need to establish what the 'leak free' figures are hence the setup described by Tony above.

I know this engine is good for well over 550bhp if we can resolve the issues above.

How much of the power is being used to drive the supercharger?

Could this be a huge number?

Ian

My Procharger C2 on my 4.6V8 makes just over half the boost of the 'OPTIMISTIC! marketing spec sheet' and I have geared it to run at the supercharger's 'suggested' max speed of 80,000rpm at my engine max rpm. I had to rebuild it has it had catastrophic bearing failure - turns out the high speed bearings were only rated to 20,000! I have since re-built it with 100,000 capable ceramic bearings.

Procharger don't publish compressor maps - just list some unrealistic 'max' numbers
For the D-1SC:
# Max HP 925
# Max Flow (CFM) 1400
Well if your engine flows 1400 CFM of air then that's around 2000hp! some somethings not quite right there.

# Max boost (PSI) 32!,
As mentioned above my C2 'rated' at max boost of 24psi makes about half that in my engine with no leaks. That is measured in my plenum so the actual pressure the supercharger is seeing will a few psi higher due to resistance on the pipework and intercooler but NOT double! I wouldn't use the 32psi from the spec sheet as an 'actual real world figure' to aim for.

WTF ? the supercharger does not "put out 32psi", that's just nonsense right from the word go as are whatever you're trying to calculate.

It moves air, it compresses air, then it discharges it. If there is a large restriction you will see more pressure, if there is no restriction, there will be none.

Stop with all the bullshit. Get rid of the notion of trying to bleed off air. And just run the thing

Assuming there are no leaks, which is easy to test, and you do not have belt slip, which is fairly easy to monitor*, then if you need more airflow, you simply need to spin the blower harder.
But low power could be many things, from an actual problem, to simply bad tuning. If you think somehow there is a big restriction....again, easy to measure. Log pressure close to the blower discharge, pre IC, post IC, and in the intake.
Likewise, log exhaust pressure....although unless there is a massive problem in the exhaust, that is unlikely to be the problem.
Some intercoolers are quite poor though so that could be worth looking at. Or just bypass the core for a quick test....being careful with tuning and watching charge temps

* Matt here fitted a single tooth to his blower pulley so he could point a sensor at it to log. You could do the same and remove any doubt about slip.....if you can see this Facebook post that is.

Just noticed this video:
viewtopic.php?f=26&t=15531&p=119368#p119368

See my comments about your belt drive - tensioner bouncing around!

stevieturbo wrote: ↑

Sat Jan 16, 2021 10:07 pm

Assuming there are no leaks, which is easy to test, and you do not have belt slip, which is fairly easy to monitor*, then if you need more airflow, you simply need to spin the blower harder.
But low power could be many things, from an actual problem, to simply bad tuning. If you think somehow there is a big restriction....again, easy to measure. Log pressure close to the blower discharge, pre IC, post IC, and in the intake.
Likewise, log exhaust pressure....although unless there is a massive problem in the exhaust, that is unlikely to be the problem.
Some intercoolers are quite poor though so that could be worth looking at. Or just bypass the core for a quick test....being careful with tuning and watching charge temps

Doh.....so that's where we went wrong

We know what the problem is. A restrictive inlet and a leaking boost modulator. There's no indication that we have an inherent issue with the engine, it spins rapidly to 7500rpm and did that easily the first time on the rollers with literally only cam break in time. It makes approx 300bhp if run NA and there's no indication that the mapping (Dale Bailey) is wrong.

Running the SC harder is not an option, it's already geared to hit its max rpm before the engine max's out.

The post above is intended to show why we have low power and whilst I am fully aware of how a supercharger makes boost I was merely trying to explain why we have low power with reference to the maximum theoretical psi that the SC is capable of, of course acknowledging that there are a host of factors in determining how this SC will make boost.

You may not like what we are doing Stevie but quite frankly that's your problem and certainly not a reason why we wont continue trying to get the boost modulator working.

got the greatest of respect for steve and you rosco - but i must admit my eyebrow raised when you said it should be putting out 32psi and further still on the 17psi of boost must be leaking and a some of the other thought process.
I'm not o-fait with the engine details, i assume it's running 45mm trumpets, associated ported manifold and 72mm plenum - there's not much more you can do on the breathing front - apart from fit a crate ls3.

However, i dont have any first hand experience of blowers - so i'm not going to venture into areas i have no direct experience in. If you find your boost leak which results in 32psi and 600bhp - i will eat some humble pie garnished with however much hair the wife manages to butcher of my head the next time it needs cutting.

Rossco wrote: ↑

Mon Jan 18, 2021 11:43 am

The post above is intended to show why we have low power and whilst I am fully aware of how a supercharger makes boost I was merely trying to explain why we have low power with reference to the maximum theoretical psi that the SC is capable of, of course acknowledging that there are a host of factors in determining how this SC will make boost.

You may not like what we are doing Stevie but quite frankly that's your problem and certainly not a reason why we wont continue trying to get the boost modulator working.

There is zero logic in how you're describing how it works, claiming it either puts out or makes 32psi. If you were to run it against a dead head, I can assure you, it would make more than 32psi. If you run it open...it will not.

And I can tell you from having already done it years ago, it is not a good way to do things nor is it healthy for the blower.

It is not my problem, currently it is your problem. Hence I am giving you plain and sensible advice from someone who has over 25 years working on and building boosted setups.

But as said, start with some basics and check for leaks and restrictions in the system. It's very easy to do with a few pressure sensors, and some DIY rigs to pressurise the entire system.

As I have said previously one problem with Procharger (including mine) is they don't publish compressor maps.
They only publish meaningless max numbers. I imagine the 32psi 'max' figure is well into the surge region.

Just for some back of fag packet numbers if you 'estimated' an engine which maybe? similar to yours in HPWizard.com at zero pressure (N/A) this engine estimate is 290hp. Similar ball-park!
If you add 15psi to the boost gauge this 'engine' now makes 445hp, at 740cfm and pressure ratio 2.04. Again similar ball park!
To get this engine to around 600hp you need to up the 'boost gauge' pressure to 34psi and it's consuming 993cfm, at 3.367 pressure ratio.

Vortech do publish some compressor maps and I had a look at their range and the nearest I could so to the procharger D-1SC was their V-1 Ti-trim.

compressor map here:
https://cdn.shopify.com/s/files/1/0780/ ... 1289603144

If you plot 993 cfm for 600hp that seems a reasonable air flow for this supercharger - BUT - not for your required pressure ratio. The 3.367 pressure ratio is way off the top of this chart.

If you plot 740 cfm for 445hp at a pressure ration of 2.04 that looks a reasonable match for this compressor.

Obviously this isn't a compressor map for your actual supercharger, but hopefully it shows the relationship to pressure ratio and air flow for a similar sized compressor.