Computer Engine Modelling, (18rg in particular)

[jeffro ra28]

I have been playing with an engine analyzer for a few days. Mainly modelling a very nicely modified 18rg.

so far i have modelled an 18rg with a max BHP of 167 and a max VE of %91.4
BSFC of .45 (which is basically spec for race)

Specs
2.2l 18rg with 10.5 CR pistons, 98 ron fuel.
298 deg cams.
I used the a flow table i had of some auto craft VW heads that were for a 2.4L VW. Which should be similar probly better to a very well ported 18rg

I would like to model it a little more realistic to what it is. For example i am using flow figures from a VW(dak dak) not a 18rg and using open headers.
If anyone would like to input information relative to a real 18rg. Specifically a proper flow table relative to their ported heads, and some suggestions for a full car exhaust system.
I am desperatly chasing CFM ratings of intake manifolds and carbies.


Or if you are curious as to what reactions different cams, turbos or watever may have to the engine, fire away and i can post the results up on here. Simply tell me your desired cams specs, or wat type of turbo etc.

This particular program has been proven to be within 5-10 hp of the actuall output of an engine. So its damn good.

[Steve M]

Does the analyser have allowance for combination cam set-ups?
e.g. 310 degree intake cam/298 degree intake cam or something similar?

Also, does it have allowance for boost so that I can get some of my cam timing figured out?

Mr DOHC had his 88270 head flowed a little while ago, some of the results went up on the old site. Perhaps he can provide some details.

I will certainly be interested in how this works out.

[jeffro ra28]

Yes it can do chain calcs with just about any combination of specs u can throw at it.
Yep boost has its allowances, it even gives u a spark advance curve. The information it provides is amazing.

Yer Mr DOHC said his head flows 233hp at 500"
What i am after tho is a complete flow table, eg, CFM ratings for each .100" of valve lift.

[Mr DOHC]

i'm stuffed if i know where that flow sheet went, i'll see if i can get another copy

it had the siffernt CFM/HP of 100/200' ect

[Mr DOHC]

how do these numerals hit ya

inlet port
lift, cfm, hp
100, 33.46, 57
200, 72.85, 125
300, 114.28, 196
400, 128.56, 221
500, 135.70, 233

exh port
100, 30.60, 52
200, 59.99, 103
300, 88.92, 152
400, 111.42, 191
500, 114.28, 196


as u can see it's pointless for me to go above 400 lift {stock} on the exhaust side as it doesnt flow enough to warrant the extra heat/friction ect ect

[jeffro ra28]

that is exactly wat i need Phil, cheers for that, now i can get a more accurate reading.

[jeffro ra28]

Can u be certain that they flowed them at 28 inches of water?

[gemtoy]

What is the software called that you are using ?
I have used a couple but they where basic amd mainly for chev and ford V8's

[Mr DOHC]

10" of water

[SRacin]

This sounds all very interested, i have WAVE and engine analyzer pro, but never really got into it. But what i would like to know is what happens to an rg with 12psi of SC14 inhancement

Cheers
Logan

[jeffro ra28]

Thanx Phil,

It is EAP

SRacin, unless u can provide all technical info on the SC14 it is hard to accurately simulate one. I need things ike CFM, pulses and most things that a SC technician can only provide. What i can do tho is load up an already existing template of a very popular turbo or SC, there are a few garrets turbo's on the list. Tell me which one and how much boost and she's apples mate

[jeffro ra28]

double post

[Mr DOHC]

hey SRacin, talk to Bluewire on these forums, he has a shoe RA40 with an 18RG with SC14 boost

[Steve M]

Sean (Bluewire) was running 125rwkw.

Mr DOHC, you were talking about the camlift and your exhaust ports.

Do you have any photos of your ports anywhere, I am currently porting my 88270 head and any pointers would be helpful, it's mostly done, but I'd like to compare it to another example.

Accounting for ideal valve clearances the lift of 88251 and 88270 cams is 9.5mm.
The lift of 88231 and 88250 cams is 10mm.

What sort of lift have you gone for on your intake cam?

[Mr DOHC]

yeh, i dont need to run that much lift

my cams are identical, 282/282 degs and 465 lift {12mm}

i'll find pics soon