bimbleuk
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| posted on 18/5/07 at 08:16 AM |
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Toyota 4AGE 20V dyno result
I've posted before about my current project to install a Rotrex SC on my 4AGE 20V Toyota engine. Well after a few delays I've got the car
back with an initial tune on the engine to run the car in before finally connecting the supercharger belt.
My engine is a silvertop 4AGE 20V 1587cc which was later replaced by Toyota with a blacktop 20V version. I chose the earlier engine as its got
stronger internals such as the con rods being much thicker.
The mods I've done are to fit bigger injectors, lighten and balance the internals plus the head was flowed to mostly increase exhaust gas flow.
On this dyno a typical silvertop would show about 145BHP and 112 ft lbs so I'm happy with my engines output for fairly minor mods.
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DIY Si
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| posted on 18/5/07 at 08:40 AM |
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It's always nice to know the work you're doing on an engine is actually worth it, and 15 bhp from a few minor things is a great result.
How much are you hoping for from the SC? Youplanning on running silly PSI, or just a couple?
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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bimbleuk
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| posted on 18/5/07 at 09:03 AM |
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Hi,
The delays were making me a stress monkey so yep very relieved to get some positive results back.
The Rotrex being centrifugal will produce peak PSI at peak RPM. So the aim has been to see 10-14 PSI at peak and start seeing useable boost from
3000RPM. The garage I'm using have a few Rotrex installs running now so I'm not expecting any major issues. If we do have problems with
detonation while mapping I already have a set of low compression pistons waiting.
For once though I do think there is a limit on the power I want in my car. So if I achieve my aim of 225-250BHP then I hope I'm not too scared
to drive it 
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MikeRJ
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| posted on 18/5/07 at 10:18 AM |
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quote:
Originally posted by bimbleuk
Hi So the aim has been to see 10-14 PSI at peak and start seeing useable boost from 3000RPM.
Wow, that seems like a lot of boost for running with stock compression (at least I assume stock compression from the normaly aspirated power).
You're going to be needing some decent fuel to avoid detonation surely?
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Dusty
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| posted on 18/5/07 at 10:26 AM |
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Is that at Mech Motorsport, Cheltenham.
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thomas4age
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| posted on 18/5/07 at 01:38 PM |
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Looking good Justin,
I would consider running less boost and keeping the stock pistons, you'll get the power in the end.
start with .6bar of boost and go from there.
grtz thomas
If Lucas made guns, Wars wouldn't start either.
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bimbleuk
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| posted on 18/5/07 at 01:49 PM |
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Dusty, yep thats Dave of Mech Motorsport who rents the rollers at Mech Repairs in Cheltenham.
I went through the same thought process you guys have. I even had the engine built with the Toyota 8.9:1 pistons at one point.
The guys at OMEX just down the road have done several Rotrex installs recently including an Elise with a Honda K20 giving 440BHP on 9:1 compression
and 2 bar of boost!!!
Richard the owner of OMEX has a Striker very similar to mine and he was going to run a bar of boost to start. Anyway they've got all the
differnet pulleys for me to try on the rollers.
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bike_power
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| posted on 18/5/07 at 02:25 PM |
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That's a good solid point to start from. The compression ratio varies with cam timing, I have 9:1 static but my cams are reasonably long
duration so the effective cr will be lower, allowing at least a bar to be used on pump fuel and I'd imagine you are in a similar position.
A Rotrex is also easier/safer to use wth a higher static cr as it doesn't make much boost until the engine is spinning quite quickly which is
when the engine can make use of it. High boost at low rpm like a turbo or positive displacement sc can supply can be a recipe for soft pistons.
Will be very interested to see your graphs once the Rotrex is doing it's thing 
Mine is booked for the 14th June, had one session already but an air lock in the cooling system cut it short, need a new radiator too in the meantime.
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Schrodinger
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| posted on 18/5/07 at 10:01 PM |
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I see from the picture of your car that you seem to be running with only half of the timing cover on considering the work you are doing PLEASE put the
rest of the cover on or if you can't take the bottom half off.
A friend could not be bothered to replace the top half as yours is and had a stone fly of the road into the timing and jumped then snapped the belt
with expensive consequences.
Keith
Aviemore
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bimbleuk
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| posted on 19/5/07 at 05:43 AM |
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Yep the cover was off for the rolling road session. There wasn't a cover on it when I bought it as it was going to be scrapped. I bought it
cheap as a result and managed to re-condition the bores without a re-bore even though two rings were rusted to the cylinder bores. I've robbed
the cover from my spare engine.
One of my previous cars was a Celica with a 2ZZ-GE engine. The CR was 11.5:1 and it had a roots blower showing 7 PSI at peak torque. That's when
detonation is more likely to happen. No issues with that engine even running 95 octane fuel.
With the Rotrex I don't belive I'll see 7 PSI at peak torque and my static CR is 10.5:1
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thomas4age
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| posted on 19/5/07 at 07:44 PM |
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That's why we love our little toyota machines, Build like a brick!
plan to run twin M45 eatons on the lexus V8 boosting 0.5/0.6Bar(8 to 9 PSI), I sure hope it'll hold up. it's got the 10:1 compresion ratio
and will be intecooled very well.
whats the biggest enemy of pistons BTW (ie melting down) to much ignition advance or plain detonation due to compresion?
Grtz Thomas
[Edited on 19/5/07 by thomas4age]
If Lucas made guns, Wars wouldn't start either.
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