98_glanza
Member +
i dont recall seein popsy graph??whats got to do with the car or mapper???im not having problems i just wnat to reduce the lag???????????????????????
Reducing Lag
- Thread starter 98_glanza
- Start date
i dont recall seein popsy graph??whats got to do with the car or mapper???im not having problems i just wnat to reduce the lag???????????????????????
GlanzaMarvin
Member +
Put in a 5.7l naturally aspirated Chevy V8. Should rid you of all lag and up the torque output.
98_glanza
Member +
I did!! and a good mapper will be able to reduce lag for you?????????? and i was using popsys graph as a reference but not sure if ther was something wrong with his car??? on the dyno graph it looked like ther was!! it was like a saw blade lol did you get your car dyno'd ?? to see what yours is like??
98_glanza
Member +
no i didnt.popsy might send it onto me so.ill pm him now.are you talkin about the wcp graph or the one in couture?
popsy09
Munster Area Rep.
that was the first graph didnt stay on that map for long ha ha
the new graph from the same mapper as above was perfect
aonghus is one of the good mappers thats for sure
98_glanza
Member +
what do you mean by lean spool?
this thread will explain it better even though i believe their talking evos http://www.geekmapped.com/forums/showthread.php?t=531
grum-glanza
Member +
i think some people have to relise that a reily big turbo on a small engine just isn't going to spool it up putting a big turbo rated for a 2.0 liter car on a 1.3 or 1.5 its not going to be the same as it was on the 2.0 but probaly the easest way to get a faster spool is get custom made cut back turbine blades out of titanium 360 degree trust bearing probaly do head work valves, springs, retaniers port and polish cams would help aswell thats all thats coming to my head at the moment
Texx
Super Moderator
A lean air/fuel mixture will increase the exhaust gas temperature and pressure, an increase in exhaust gas pressure will decrease the amount of time it will take to spool the exhaust side of the turbo. Obviously if the exhaust side spools quicker the compressor side will also spool quicker and so turbo lag will be reduced.
Similarly ignition timing can be retarded to the point where the air/fuel mixture is still burning when the exhaust valves open, in doing so the burn will increase exhaust gas temperature and pressure which will decrease the amount of time it'll take for the turbo to spool.
Similarly ignition timing can be retarded to the point where the air/fuel mixture is still burning when the exhaust valves open, in doing so the burn will increase exhaust gas temperature and pressure which will decrease the amount of time it'll take for the turbo to spool.
If you retard the ignition timing though, won't the motor be down on power? Seeing as the exhaust valve will be open before the piston reaches BDC and the exhaust gas escaping meaning a drop in thermal efficiency? As burning the fuel is what creates a majority of an engines power through heat energy.
Texx
Super Moderator
Ignition timing wouldn't be modified throughout the entire load range and the engine will be down on power before the turbo spools anyway, it's a matter of modifying the fuel and ignition maps to bring the turbo on song quicker. Once the turbo is producing positive pressure the spark and fuel maps would obviously be made to suite the conditions and requirements of the engine.
Guye
Lifer
Agreed. Over the years I've noticed guys gravitating towards increasingly larger turbines for the starlet. Granted, advances in turbine design now allow for some larger units that are more responsive than smaller units of yesteryear. By now many have experimented with and know about different setups and and little "tricks" with i/c and exhaust pipe diameters, utilizing the venturi effect, gain settings on the ebc, porting, polishing, ignition timing maps, lean spool etc. The simple fact of the matter is even if you could somehow succeeded in achieving a volumetric efficiency of 100% on a 1.3 or 1.5 liter motor, there is still a minimum required exhaust gas volume needed to spool larger turbines...can it be delivered at a low enough rpm to erase/limit lag on small displacement engines? The engine itself (which is essentially a pump for moving air/gases) become the ultimate limiting factor. It is an easier (an time proven) science to use a smaller low-mid rpm turbine then make "changes" to strengthen it's top end power delivery than to take a larger, high rpm power turbine and try to improve it low-mid rpm characteristics. Just my opinion.
Last edited:
I don't think the 1.3 would flow enough exhaust gas pressure to spool a big twin scroll turbo with a big turbine housing although i would like to see it done. Another thing is you cannot even dial the cams in on the 4E which would help reduce lag because it is not a true twin cam, this way it would be possible to raise compression of the engine with more precise valve timing and create higher pressure exhaust gasses. I think on a small engine main factor to look at to reduce lag would be exhaust manifold design like runner length, width, collector angle to hit the exhaust gas on the turbine wheel at it's most effective point, port matching and custom or smaller turbine housing.
I'm using a vf34 dude not the most responsive turbo I must admit lol.
JonoPhilpott
Member +
Drive it hard enough and you'll never drop enough revs to be out of full boost.
Took me a while to learn how to drive my car again when i transformed, you get to know at what speed you can drop into 3rd etc For Me 70mph is 3rd and is at full boost and pulls for another 2.5k .... Full boost at 90 in 4th etc.etc..
Anti-Lag ... Simples
Took me a while to learn how to drive my car again when i transformed, you get to know at what speed you can drop into 3rd etc For Me 70mph is 3rd and is at full boost and pulls for another 2.5k .... Full boost at 90 in 4th etc.etc..
Anti-Lag ... Simples