1497 replies to this topic

[NickB787]

am in Europe at the moment so no not yet I hope to get it all sorted next week. Will have a check of everything when I get back

[Nev]

Jeeze, you fly boys have a shite life - you never seem to be at home ! Is it road legal BTW ?

[NickB787]

well I'm back, so I can crack on I am certain the manifold is the restriction now, need to start looking into that when she is up and running, want to see how the ecu transplant went not road legal yet bit of work to do first

Edited by NickB777, 23 November 2011 - 03:03 PM.

[Nev]

You can get a company like Pro-Alloy (or other lesser known fabricators) to use your existing manifold to make a better one BTW. It's not really rocket science, just basic rules of thumb will improve the flow considerably. If you read my blog, I did a experiment to look into this which explains it better.

[VX-GT]

You can get a company like Pro-Alloy (or other lesser known fabricators) to use your existing manifold to make a better one BTW. It's not really rocket science, just basic rules of thumb will improve the flow considerably.

If you read my blog, I did a experiment to look into this which explains it better.

Actually working gas dynamics is pretty close to rocket science

[Nev]

You can get a company like Pro-Alloy (or other lesser known fabricators) to use your existing manifold to make a better one BTW. It's not really rocket science, just basic rules of thumb will improve the flow considerably.

If you read my blog, I did a experiment to look into this which explains it better.

Actually working gas dynamics is pretty close to rocket science

I accept you could apply rocket science to it, but a simple 1 hour redesign (a la David Vizzard) would likely yield 80% of the improvement that 100 hours of detailed theoretical/experimental gas flow analysis would. I was trying to give a practical solution to Nick that he could actually achieve, rather than descend into idiology just for the sake of it.

Edited by Nev, 23 November 2011 - 05:08 PM.

[The Batman]

you got a spare hour nev?

[siztenboots]

[Nev]

If you read Vizzard like I did, he gives some ball park explanations and formulas to get your going. An hour of fiddling with them should be enough. Actually fabricating the thing will take a day or maybe a bit more for Pro-Alloy. I rang Alex up and he gave me a discounted quote of approx £450 to make one up for me, based on my cut down OEM runners. In a charged car like Nicks the design of the inlet runners is less critical/finickity in general than an N/A where every BHP is harder to glean. I know guys on MigWeb who have got a genuine extra 30 BHP just by fabricating new inlets for their 400 BHP C20LETs without even using any calcs at all (ie, just opening the runners + plenum out by approx 20% to 30% at a guess). If you start doing things like tapering the runners and calculating the lengths of the runners to suit where you want the peak VE to be, you can start controlling your design more. After that you I suppose you can get into CAD, resonances, equalising runner pressure by +/- 1% and all that malarky, but it won't gain you much more than 5 or 10 BHP at the most on an engine like Nicks IMO. To take an example, the very expensive Klassen inlet I bought (and partly regret) was modelled using CAD and flowed on a computer and went through several design processes and 3 actual castings. However, even after all that it has flaws and I personally think it induces a flat spot at 5600 RPM. I see this flat spot on my dyno plot and on others that Klassen has sent me (from engine with quite diff turbos etc etc). Without sounding arrogant I think in retrospect I could design an inlet manifold that would produce similar benefits (or more power if I was willing to lose torque at the low end) - it's just a matter of reading a bit and doing some calcs as I said. I even came up with a dynamic design which you could modify with a screwdriver, this would allow you to tune your car for track day/road day. I then discussed the matter with a Phd student in one of my car club meets and he then told me that in fact Saab had come up with a similar concept 10 years ago that nearly got put into production. Alternatively, you could just keep discusing it, but hopefully I have given Nick viable/practical way of sorting this issue.

Edited by Nev, 23 November 2011 - 05:46 PM.

[Nev]

Here are some dyno plots with completely different engines/turbo/cams etc etc. A common denominator is the inlet manifold which makes me think the dip at 5600 revs is caused by this part.

Klassen Engine #1
Nipper #2

[Nev]

you got a spare hour nev?

Yes, I'm bored to death without a car that needs fiddling with - why, whats your idea ?

[Exmantaa]

The ideas are there, but the main problem with the SC manifold is the available space and the integrated chargecooler. If we only could improve the cooling / flow surface AND mount the SC on it, we would already be very happy...

[Nev]

I know little about your supercharged setups compared to you guys, but it strikes me that for proper charge cooling you need a complete ground up design which separates the parts into their logical functions (a bit like a single Hi-Fi being split into a separate pre-amp, power-amp, tuner etc etc).

Thus I would imagine you need:

1/ A supercharger that is physically distinct from the manifold with normal round inlet and outlet pipes.
2/ A remote and bespoke CC matrix (like the Pro-Alloy one for VXTs). The outlet from the supercharger would pipe to this.
3/ A brand new bespoke inlet manifold that is fed boosted air from the CC matrix.

All this would be quite expensive I imagine and would require a (rich) 'test dummy' for R&D... Ultimately (and as you know I'm not a S/C basher at all) you are chasing a lost cause due to the inhierent diminishing efficiencies of supercharging in comparison to turbocharging. I think Nick and Joe are already knocking on that door at 380 BHP. Getting 190% VE out of a SC'ed small engine is pretty good really, hats off to you. American V8 superchargers rarely even achieve 150% VE before they switch to turbos from what I've seen (look at the highly respected top-end Nelson engines to see what I mean).

TBH, 380 BHP and the super smooth delivery of torque in your cars will make them top dog on small to mid sized tracks, so I don't personally think you need to chase any more power as track cars. I think the only time you'd lose your podium spots are on big tracks or road circuits like the Nurburgring where power is dominant.

Edited by Nev, 23 November 2011 - 06:39 PM.

[Exmantaa]

Thus I would imagine you need:

1/ A supercharger that is physically distinct from the manifold with normal round inlet and outlet pipes.
2/ A remote and bespoke CC matrix (like the Pro-Alloy one for VXTs). The outlet from the supercharger would pipe to this.
3/ A brand new bespoke inlet manifold that is fed boosted air from the CC matrix.

The above is actually pretty simple:
- Buy Rotrex supercharger and mount in AC pump location. (C30-94 should do nicely I think)
- Fit the aluminium Saab B207 manifold. (maybe mod the TB pattern)
- Make a bespoke chargecooler in between and some plumbing skills needed.

Done.
Needs some bespoke mapping, but pretty doable and this should make awesome power up top. (And less weight too!)
But that's probably not what the majority want (proper mapping is a problem) and not sure if I will like the torque delivery of a centrifugal SC.
(But the above combo was and still is lurking in my back mind, especially as I am now able to properly map the VE table in my LSJ ecu. )

Edited by Exmantaa, 23 November 2011 - 11:59 PM.

[The Batman]

Genuine offer Nev if you are bored and around on Saturday feel free to pop toys mine and be noisy My intake manifold will be off for some tweaks anyway

[Nev]

Thx Joe, but on Sat I am having a B'day meal with my parents and bro who has come down from London, so can't escape On Sun, I am commited to a meet with the SW VXers.

[NickB787]

Doing a bit of reserarch

Here is a good read http://www.hotrod.com/techarticles/engine/hrdp_0907_gm_ecotec_bolt_ons/viewall.html

I changed my 3"(80mm) to a 2.8" pulley when I reinstalled everything (forgot to Tell Courtenay’s though) I think that may have been a bad choice, all it does is heat the air up, when I have been running for a while to make certain there are no problems I will drop to the 2.9 and see if that makes a difference to the temps
A radical redesign of the intake manifold is needed it seems

[VX-GT]

Doing a bit of reserarch

Here is a good read http://www.hotrod.com/techarticles/engine/hrdp_0907_gm_ecotec_bolt_ons/viewall.html

I changed my 3"(80mm) to a 2.8" pulley when I reinstalled everything (forgot to Tell Courtenay’s though) I think that may have been a bad choice, all it does is heat the air up, when I have been running for a while to make certain there are no problems I will drop to the 2.9 and see if that makes a difference to the temps
A radical redesign of the intake manifold is needed it seems

Only an hour job for Nev

[NickB787]

Not certain there, reading this and other articles certainly makes me want to stop putting money into this thing, HP per £ from here on is going to be stupid

Edited by NickB777, 25 November 2011 - 11:42 PM.

[The Batman]

be-jebus that m90 charger is HUGE looks like it weighs more than me (not quite as much as atoms head though )