924Board.org

Arvidw · Posted: Tue Oct 11, 2011 3:43 pm Post subject:

@Martijnus, okay thanks!

@Raceboy, unfortunately i'm not able to create and tune a brand new VE table as fast as you can. It takes me a full fuel tank to create and fine-tune the VE table which includes a trip to Germany to tune under constant full load. Maby i'm more thorough than you because my car is a road car, or many i'm just terribly inefficient.

(Tunerstudio MS efianalytics)

Either way, redoing my current fuel table takes me far less time because I don't have to start all over again.
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

I have only one race-car and all of my other cars that have standalone's are street cars.
Nothing more to add, it's your car and you can do how you prefer I was just giving you ways how to easier solve your issues with driveability.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

Arvidw · Posted: Tue Oct 11, 2011 4:47 pm Post subject:

Okey, than I'm just dreadfully slow

Please don't get me wrong. I'm very pleased with your advise because you have far more experience with this than I do. You presented a alternative solution to my problem and made me rethink my current idea

I'm taking my engine out in a couple of weeks, this is a major opportunity to create a better EFI setup from a mechanical point of view.

Do all your injector fire at once or do you (semi-) sequential injection? (Mine all fire at once)

Do you see any benefits in running MS with a camshaft sensor? (full sequential injection)

Do you use wasted spark ignition on your engine or COP's ?
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

I think tuning for the road takes more time for the details. I set the VE to 0 at 0% tps, which seems sensible (no throttle and not idle = deceleration = no injection), but that needed some tweaking to get it smooth.

Those are still details and the rough stuff, which has the most influence, can be done easily.

The part I found the hardest is finding sensible AFR values as a goal. Never took the time to optimize my ignition tables and I used the 'stock' mapping from a 924.

Don't do everything at once. COP is all fun but expensive (those things need replacement a bit too often imho), sequential injection doesn't really seem as a big advantage according to most MS users (but that doesn't mean it isn't better).

Just remember that if you CAN control stuff, you'll have to be able to know what you're doing. COP is great, if that's the weakest link in your system. I'm not sure what exactly is the advantage of COP but it probably produces a stronger spark and can be controlled with a higher resolution. That higher resolution means you'll have to work in the significance of that resolution; in other words: you won't have an advantage to be able to tune ignition three to the thousands x.xxx, if you just use full degrees.

Just start simple, I started with fuel only. You can always expand the system and make it complex, but it's very very VERY important to understand the basics and become familiar with everything regarding tuning.

Some radical modifications in the system, like moving the injectors, can have radical influences which you'll have to anticipate.

It's fun to do, but don't make it too complex too soon

You're in my msn list iirc, so you can contact me anytime. Don't have as much experience as raceboy, but at least it's something

_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

Arvidw · Posted: Tue Nov 15, 2011 11:05 pm Post subject:

@Martijnus, i think i'll stay with wasted spark ignition but upgrade to sequential injection. Maby i'll change my mind in the next months while the engine is out.

However first i'll have to find another engine. I took mine out because the compression wasn't great, it was leaking oil and was rattling a little.

Some highlight way is broken:

2x cam folower. (fortunately no real damage to cam)

Some (5) worn valve springs.

Some (2) worn / damaged connecting rod bearings.

Boken piston ring and damaged piston ring groove in piston

Worn / damaged main bearings

Worn / damaged crank

Damaged cylinder wall due to rust (probably water in cylinder in the past)

Nackered valve stems (many)

Thats not al, nearly everything is broken. This block is going to be scrapped

It is hard to believe that this engine reached 210km/h at GPS 400-500km's before I took it apart. Apparently these engine's are not entirely bulletproof but will keep on going even though nearly everything is damaged

(with good oil pressure btw!)
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Good grief!

I thought mine was bad with the shattered exhaust valve face and broken exhaust manifold!

They are tough, but nothing is completely impervious to wear and damage.

Good luck with the new build.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Arvidw · Posted: Sat Nov 19, 2011 5:56 pm Post subject:

While searching for engine parts i came across an affordable eaton M62 / M64 blower. After seeing multiple awesome projects at this forum I think this might be the road to take.

I want more power from my engine however creating more power in NA form is quite expensive. (pistons, rods, big valve, balancing) Boosting the stock engine with 0.4 bar of boost and keeping the original or even a lower rev limit may also result in a couple HP gain. I'm not looking for clutch slipping transaxle breaking performance.

Which one is more suitable for a low boost application?

M45:

M62:

I suppose it is the M45, however what problems will I have running a M62 on low boost? (M62 is nice because of the clutch and possibilities to run high boost in the future)
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Your M45 map won`t load but forget it anyway, its too small.

Speaking from experience, you will not want to stay at a low boost level for ever anyway. 6.5K stock RPM is no problem even with much higher boost. IMHO the major reliability and performance degradation factor really depends upon the drivers attitude & maturity. Sure any fool can kill a transaxle with USA NA power levels by dropping burnouts. That said, the increase in low and midrange power will more than put a grin on your face while completely wiping it from many turbo drivers who will only pass you at illegal speeds after you have throttled off.

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World`s quickest 924 2L slushbox

Arvidw · Posted: Mon Nov 21, 2011 2:44 am Post subject:

Perfect, then i'll try to find a M62.

How much cc does your (toyota?) roots blower pump every revolution? I'm trying to calculate the correct drive ratio for the eaton M62 however I have no refference to check my calculations with. (need a good approximation of the VE of a blown 924 engine, i may be able to approximate it using the date from your topic + blower size)

I saw you are running around 0.8bar boost with and without an intercooler. What is your opinion about running 0.4-0.5bar of boost without an intercooler? Would you feel comfortable running the engine flat-out for couple of km's ?
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

the_mad_electrician · Joined: 16 Nov 2009 Posts: 1073 Location: Central Georgia

Martijnus · Joined: 29 Dec 2006 Posts: 2019 Location: Netherlands

I've got a rebuilt (10k km/lpg/ITB etc) and MS converted engine in my garage... plug & play. But not sure if I want to sell yet. Intended the engine to be placed in my next 924 but in the mean time I'm already building a 8v turbo and a 16v (na/turbo not sure) XK engine.

Building engines is more fun than driving the car

Your engine has some serious damage. Not sure what caused it. Is only one con rod bearing worn out? or all? and those valves could be caused by too much clearance or the worn springs.

Someone didn't take good care of that engine in its lifetime (not implying you, but previous owners)

edit: the engine I mentioned above has a raised compression ratio, so if you want to charge it some mods are necessary internally.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

Lizard · Posted: Mon Nov 21, 2011 4:02 am Post subject:

Naw, go big or go home. Put an M90 on there. :p
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3 928s,

Arvidw · Posted: Mon Nov 21, 2011 6:00 am Post subject:

@The mad electrician, thanks, I send you a PM

@Martijnus, I'm able to source a good bottom-end for 200euro's, i have a good spare cilinderhead lying around and need some gaskets and accessories for 150euro's. I suppose you are not willing to sell your engine for lets say 350-400euro's

I agree the engine has not been treated correctly by previous owners and probably me. However this engine was perfect for me to learn Megasquirt on and held on even though the AFR and ignition timing wasn't correctly all of the time.

I'd rather ruin an old worn engine than a freshly rebuild one.

@Lizard, Maby add some cylinders to be able to drive the M90 SC ?

_________________
Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Arvidw · Posted: Mon Nov 28, 2011 8:09 am Post subject:

I have been reading multiple project treads and have to say they are a wonderful source of information. Thanks for the tip RC

However I discovered that I made a crucial mistake for installing a supercharger in the engine bay of a 924: I took out my engine before taking any measurements.

I've been trying to work out the clearances using pictures however this isn't accurate enough. So I will focus on building a good NA engine and installing it first before I start with the SC project.

The engine will stay 1:9.3 CR, i'll add an extra set of injectors in the head, move the trigger wheel to make room for blower pulley, move dipstick etc.
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Porsche 924 2.0 Kompressor 136.1wHp @ 5650rpm / 201.9wNm @ 3900rpm (dyno @ dp-engineering.nl)