4GAE tuning for fast road use

[JMR_AW11]

Here's a little light reading (?) on Fluent when applied to the automotive world...

It's only 12 pages but it takes a while to download as it's a glossy brochure.

http://www.fluent.com/solutions/brochur ... -final.pdf

[JMR_AW11]

I just checked which SW we use for fluid analysis at work and it's called CFDesign.

The guy who uses it says you have to draw your design in an external 3D package and then import it before simulation.

He reckons it can analyse air pumps quite well so it should give fair results on a simple engine model.

We use it for thermal management mainly, esp for fan cooled designs.

Is this comparable to Fluent or should I try for a Fluent demo?

[Jim-SR]

Fluent is awesome, but if youve got something else, give it a try. i dont have access to Fluent, just FloWorks, which is a Solidworks add-on. its reasonable enough for accuracy. it cant model to absolute perfection, but if you know how things should behave and then you see what Floworks is kicking out, you can apply your own thinking to its results and read between the lines to figure out exactly what must be happening.

comparing it in terms of external airflow, e.g. aerodynamics over a car - you can stick a car in a full scale wind tunnel, and it will give you a set of results, as accurate as you can ever simulate. but its still how those results are interpreted which leads to improvements. having 100% accurate data is no good if you cant apply your own thinking to it, so even if CFD is only 70% accurate, its refinement gets me closer than i can get with a complete guess straight off the top of my head. and it can also serve to agree with me (or disagree) on design changes

if you can get hold of Fluent then go for it. there is a lesser version called Fluent Flow Wizard which is loads better for beginners as it is more of a "wizard" with less manual configuration required. youll need a fairly fast computer to run big models with though, im talking top end server spec here too. a dual Athlon failed miserably on a complex car model

[jimi]

I've always thought about junking the airbox for a cone filter but I played with this on motorbike engines years ago and it's not until you fit the standard airbox back on that you realise what mid range torque can get lost with the cone filter.

I fitted a cone filter to my 1b a 6 months ago, changed back to the standard setup 2 weeks ago. The car sounded faster with the cone filter, however on changing back it actually feels faster, especially in the mid range when cruising about 65 and accelerating to overtake without changing down ( ie mid range torque ) no figures to back this it up, just the butt dyno.

[firstmk1]

I used Recardo Wave to deisgn the exhaust system for the formula student car in my final year at university.

[coverco]

This makes me feel old, when I was at Polytechnic we had BBC b computers and DOGS CAD. Everything else was worked out using pencil and paper, there was no software available so it was easier to do everything manually than write the software required.
How is your engine coming along Ian?

[Jim-SR]

Ricardo Wave is awesome, its just typical that my university got a copy of it the year after i left!!!

[Bender Unit]

Can anyone tell me what sort of compression is realistic and usable on a 4age? I am looking to build up an engine for the N2 and just gathering the info I need for the moment. Forged pistons would be used, I just want to know how high I can go compression wise without the need of specialist fuel. The N2 is a track car so I dont car about road drivability as long as it flies on the track.

[Lauren]

Can anyone tell me what sort of compression is realistic and usable on a 4age? I am looking to build up an engine for the N2 and just gathering the info I need for the moment. Forged pistons would be used, I just want to know how high I can go compression wise without the need of specialist fuel. The N2 is a track car so I dont car about road drivability as long as it flies on the track.

Would have thought 11.5:1 would be about the limit.... Its one of those things that isn't often mentioned on a build, because i'm guessing its a PITA to work out (teet pappettes etc).

/i might be wrong.

[luthor1]

Get towards the mid 12's on compression ratio, I used to run Mini engines up to the mid 13's. Just gotta watch your ignition.

[Lauren]

Get towards the mid 12's on compression ratio, I used to run Mini engines up to the mid 13's. Just gotta watch your ignition.

yep, i err'd somewhat on the conservative side, more for longetivity than anything else.

[LimeyMk1]

Don't know if this is of any use James. Of course we have to figure out what the comp ratio of the UK 4AGE is first.

According to this it's 10:1 http://www.geocities.com/MotorCity/Pit/ ... gines.html but I guess your engine (being Jap spec) will be 9.4:1 James.

Originally Posted by Bill Strong
This is on stock un-modified heads and stroke.

Stroke is 3.03" (77mm)

Standard TVIS 4age N/A

9.4:1 old skim 0.020 = 9.9:1
9.4:1 old skim 0.035 = 10.3:1

10.3 High comp small port 4agelu N/A

10.3:1 old skim 0.007 = 10.5:1
10.3:1 old skim 0.023 = 11.0:1
10.3:1 old skim 0.037 = 11.5:1
10.3:1 old skim 0.050 = 12.0:1

SilverTop 4agelu 20v 1992-1994

10.5:1 old skim 0.016=11.0:1
10.5:1 old skim 0.030=11.5:1
10.5:1 old skim 0.043=12.0:1

BlackTop 4agelu 20v 1995-1999

11.0:1 old skim 0.014= 11.5:1
11.0:1 old skim 0.028= 12.0:1
11.0:1 old skim 0.040= 12.5:1



Large Port GZe

8.0:1 old skim 0.029 = 8.5:1
8.0:1 old skim 0.049 = 8.9:1

high comp small port GZe

8.9:1 old skim 0.005 = 9.0:1
8.9:1 old skim 0.014 = 9.2:1
8.9:1 old skim 0.018 = 9.3:1
8.9:1 old skim 0.023 = 9.4:1

[Jim-SR]

Can anyone tell me what sort of compression is realistic and usable on a 4age? I am looking to build up an engine for the N2 and just gathering the info I need for the moment. Forged pistons would be used, I just want to know how high I can go compression wise without the need of specialist fuel. The N2 is a track car so I dont car about road drivability as long as it flies on the track.

Would have thought 11.5:1 would be about the limit.

which is why im considering running mine at 13:1

sensibly, you want to stay around 11:1 if youre intending to use pump fuel. get it mapped correctly and it could still run happily on premium unleaded (95 RON).

having seen your question in another thread, and given the amount of money the engine you want to build could inevitably cost, have you considered getting a Formula Atlantic engine from one of the teams in the States? there are lots and lots of surplus engines kicking about in workshops at the moment, and they can sell for under £10k with a recent rebuild. youve got a 1000 mile service interval, and only one place in the UK which has any great experience with the specific application of the engine, but its worth looking at. you could detune the engine (downgrade the cams, change the fuel map, drop the rev limit to 9000rpm) and run it comfortably for 5,000+ miles though

[kelfunstar]

wow. you boys have some money!!! i just want 140 bhp. ive got an air filter and exhaust now im after a chip and some cams. does anyone have any other cheap suggestions?

[firstmk1]

My aim is 160bhp but it's more about the learning experience than a power figure. If I was being sensible I'd sell up and buy something else but I'm interested in the tuning methods. Also, I can't afford my replacement choices!

The Haltech has been bought as the GEMS was just fine for getting power but was short on some of the fine tuning features that will make the engine more useable as an everyday road car. Plus it'll allow me to make the most of a few other items of interest.

I'm not sure about the rev limit as yet, any ideas on what should be included to keep the engine sweet up to say 9k?

[Jim-SR]

standard rods (late spec 20mm big ends, in PERFECT condition) are good for 8500rpm with ARP rod bolts. over 8500rpm and youll need forged steel rods, from the likes of Carrillo, Pauter, Eagle, etc

personally i wouldnt push standard rods past 8000-8200rpm without them being crack tested though, if a rod lets go it will take out a minimum of 1 piston, 4 valves, a cylinder head, potentially the block and crank as well, and if it puts a hole through the block you can even set fire to your engine bay and the entire car. worse case scenario, but its not really worth the risk

the rods are good for 200bhp+ though if you can get it within 8500rpm, so you dont really NEED to go forged, only if you want to rev higher. Carrillo rods are supposedly safe for 13,000rpm on short rebuild cycles. its just that you cant buy a piston which is strong enough for more than 11,000rpm reliably (and by reliably, im talking 600-800 mile rebuild intervals!!)

the most id push Wiseco pistons is 10,500rpm but if you can get the Mahle/TRD Atlantic pistons they are probably safer for 11,000rpm being lighter and allegedly stronger

[jrleech]

Forged rods are pretty cheap for the Mk1.... I picked up a set from THS Rods for £255 (which I thought was a damn good price:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... &rd=1&rd=1

and now these guys are doing them for £235 Buy It Now (look identical to the THS ones, which look identical to the Eagle ones with the same specs): http://cgi.ebay.co.uk/H-Beam-Rods-4AGE- ... 0136408854

Claim to be good for 9000rpm / 600bhp, which is enough for me

They weigh 408g each, anyone know what a stock (late) rod weights?

[dex]

They weigh 408g each

That's lighter than Pauter rods, they weigh in at 497g each (with bolts).

[jrleech]

They weigh 408g each

That's lighter than Pauter rods, they weigh in at 497g each (with bolts).

Ahh, that weight doesn't include the ARP bolts, so probably pretty similar.

[dex]

anyone know what a stock (late) rod weights?

459g for rods with 18mm dia little end
526g for rods with 20mm dia little end

I'd guess this is without bolts but I don't know for sure.