[TD04G16ASJ80]

Hi all,

I have all but finished my G16A turbo project. (Carby)
I just have two things I can't figure, some help will be appreciated

Where can I take the vacuum from to control the blow off valve? I have the boost lines under control but can find a decent vacuum

I have a pyro guage to help tube the carb so I know when it's running too hot or cold. What's the target range? It runs about 550-700 degrees at the moment with 3.5-5 psi fuel pressure on no boost.

Thanks all

[JrZook]

Vacuum for the BOV should be taken from the intake manifold after or downstream from the carb or throttle body butterfly valve.

The pyro will be an interesting way to tune it. The EGT should peak at the stoich 14.7:1. On either side of this AFR the EGTs will drop. This is further complicated by the change in EGTs due to ignition timing, so it really becomes tricky to work out whether you are running safe or not . Ideally you would want a wideband AFR gauge to tell you exactly whats going on.

With just a pyro you will also have to rely on plug colors/conditions as well as seat of the pants to access your tuning attempts.

[Gwagensteve]

Wouldn't egt go higher if the afr goes lean?

[TD04G16ASJ80]

Thanks JR Zook.

I was pondering on a Wideband, however i have never used one for my usual carby business and i am easily confused. Im used to doing it by ear/seat of pants as advised.

From my understanding the EGT will reduce if it runs lean or rich....

Im not buggerising around with the carb (its off a renault G5 and is new/pre tuned). I am basically tuning from the timing perspective. I now that it has to be retarded slightly, so i am running it until it pings then retarding.... until its clean on full boost. (only 7PSI on a TD04)

I have tried to google a rough operating temperature guide for the EGT, it seems no-one uses them on fuel.... Diesel seems to be safe under 550 celcius.. so should i expect higher for Petrol?

Just seeing if anyone knows what is safe...

Also with the vaccum, does anyone know where i can "t" one from on the original G16A engine? i cant seem to find one. there is a larger pipe coming from the intake to the rocker cover and the intake. Could i somehow dodge "T" this, would it have the vaccum to open the BOV?

Thanks for the help guys.

[Scrawny]

Have you done anything to the engine internals? I would've thought 700 would be on the limits of even a ceramic coated piston?

[TD04G16ASJ80]

Hi Scrawn,

Standard internals.... 700 may be the limit.. thats what im trying to ascertain so i dont fry the engine. There is no overheating issue at all runs as normal.... I can advance the timing back a little more.. however then it is almost at the original timing and detonation may be an issue..

[JrZook]

There's a little bit of info I posted in here regarding dizzy modifications that may help you. viewtopic.php?f=4&t=13720&start=120

I still reckon you would be best off grabbing a wideband gauge to help justify what you see on the EGT. The AEM ones seem pretty good and go for around $200 new.

Have you modified the renault carb to suit the characteristics of the G16A ie jetting etc? If you are worried about frying an engine it would be a bit naive to assume that it would be a bolt on and run safe in terms of AFR's with no tuning required.

[TD04G16ASJ80]

Ok.. Ok, it seems like wideband is the only way to tune it correctly. As its turbo carby low psi I think only a low retard is needed.

With the carby, it was not just a stab In the dark.. The C2J engine is very similar to the zook. 1.4 8v turbo similar in most ways with a much higher output and fuel offering, hence I assume very little tuning required.. I will get a wideband and let everyone know how close a match it was if anyone is interested in doing a similar conversion.

BTW petrol EGT reading (depending) should be ok to 800 degree on WOT if anyone needs to know.

Thanks all and I will let you know the outcome.

[vet 180]

Wideband for sure