Car running slow and theory to bounce off you guys.

[cagri]

as long as 2 turbos are in their efficiency range they will make SIMILAR(not same) hp and flow similar airflow through the engine. The rpms that they will be making that hp or torque will be different because of their spool times and efficieny differences. 10 psi is 10 psi on both 50 trim and t25.

However at higher rpms T25 will be blowing more hot air through the engine and thus it will be making less hp at higher rpms whereas 50trim can easily supply enough air for the engine at 10 psi at higher rpms and it will be making more hp at higher rpms.

The reason why t25 feels faster at 10 psi is that t25 spools extremly fast and thus gives you the allusion of being fast because of that. When 2 cars, one with t25 and another with 50 trim go WOT at 3000 rpm, you will notice that t25 will get a quick jump ahead of 50 trim car, that is the feeling of sudden spool and torque, but as the rpms climb up 50 trim spools it will slowly catch up because 50 trim will be makimg more hp at higher rpms because of cooler air it supplies and thus engine is doing more work for each revolution. At higher boost pressures t25 will be out of its efficiency range and cannot keep up with the air demands of the motor and 50 trim will catch up much faster and fly by it.

 

[AL92]

ninety7gst....if I just read right you are running 22 psi on a 50 trim on stock sidemount?
If so without water injection or a big front mount you must be retarding timing like crazy and have knock off the charts!!!
I would expect your car to be slow a heck right now with that combo. Sweet and I both found we could run around 10 to 12psi or so on stock sidemounts with our 50 trims.I think I can push that much higher on just my water /alcohol injection and might try that first but a big intercooler is a necessity on a 50 trim size turbo.

And I have 650s too and big pump but still no way could run much over 12 for very long with stock sidemount setup.

 

[ninety7gst]

thanks for answering my question cagri.
and AL92, i need a bigger intercooler u say? that would explain the fell i get when im up twords 5.5krpms and higher... wut one would u recommend?
oh and what is this water/acho injection you're talking about?

 

[AL92]

You have a second gen you have lots of bolt on intercooler choices.We usually have to modify a bit on the 1gs to get the bigger ones in.Just look on the sponsors sites and pick big one..
And as for water injection there are many kits to look at .I got my system from
www.coolingmist.com
It looks very good and is dual stage meaning it shoots a bit pre intercooler and then a bigger amount post intercooler.Supposed to work real well find out sooner or later when get it in.Its winter big time here so not easy to work on my car without a warm place to do it.
I can't believe you are running 22psi on your stock intercooler with like a 50 trim.Its just not possible.Something is weird there or like I said you have no timing and due to massive knock retard.

 

[Batty200]

......But I swear if can't get mine working decently its going to be gone and a evo big 16 or ball bearing turbo will be in its place......

I hear this allll the time. IF your car sucks with any turbo it is YOUR FAULT. I see people selling turbos all the time and saying they sucked but really it was a bad install or tune. Do not change setups if you cant get it right as that will only complicate matters more unless a part is BROKEN!!!!!!!!!!

Better yet HIRE A PROFESSIONAL!!!!

Later

 

[sweet97]

How about a compehensive "tuning guide" that can be used by the guys using dfferent tunng methods/tools. I have the MAF-Translator. Other guys use something else. Looks difficult to find 10 guys who will agree on a tuning method just like agreeing on what turb will do what.
Sure each motor is different but I doubt one is running best at a 10.5:1 a/f and another at 12:1. How much knock is acceptable? I hear 7 counts is the limt before pulling timing, maybe 10 counts is just fine? Anyone successful care to share? Mark

 

[cagri]

I normally don't post but there are so much mis information in this thread that I could not hold myself.

Ok first of all, the only way you will be able to find out what is really going on with your car is if you have a real tuning tool like DSMLink along with wideband o2 sensor. I don't care what you say about S-AFC or MAF-T, you cannot tune your a DSM car with those tools accurately.

At best it will be a rough tune, and you don't really know what you are doing or what is really happening in your car because;

1-) you will be hiding air from ecu,
2-) thus you will be put on a lower air flow map
3-) and in turn you get more timing,
4-) and because of that you get more knock(with pump gas),
5-) and finally because you cannot run high timing with shitty pump gas
6-) and as a result of all the knock you are constantly getting you might damage your car.

Even if your timing looks good with S-AFC you may still be knocking like hell depending on how much air you are hiding. (This is only true for 2G guys that cannot see knock, 1G guys can already tell they are knocking)

Now when you have a real tuning tool like DSMLink you will not be hiding any air, and you will see when you knock and you will notice that even 1 count of knock will pull a little bit timing off, and the good thing is you won't knocking because you will be on the right timing map just like the ecu has intended your car to be. And if you run race gas you can always add more timing if necessary.

In short, please watch what you are doing with SAF-C and MAFT type of tools, and get at least a wideband along with a logger to see roughly what is going on. And I strongly recommend get rid of those and get a real tuning tool.

 

[sweet97]

Thanks for a reply with facts and without critism. We are here to learn, I am anyways! I have a 1G, NO DSM link yet. I DO have a good boost gauge, a wideband and a Scanmaster which will show me 02 voltage and knock or timing in real time so having the facts available is there. A Walbro just went in and an AFPR is here next.
Now I need a good gide for tuming. Tune by knock? timing? How would you do both? I know my motor likes an A/F of 10.5-10.9:1. That's done. I am getting much closer. The difficulty in this post is trying to figure out how someone's turbo "feels"! Mark

 

[cagri]

sweet97,

The first thing I would do is making sure that your motor is in good shape(good compression, good plugs and wires and etc...) and you have no boost leaks.

Once you took care of the above;
I would set my boost controller to something like 10 - 13 psi range, the reason is it is much easier to tune a car at low boost, and even if you make a mistake you are not risking your engine by running high boost at the same time. Always be safe.

Then i would do a 3rd gear pull from 3000rpm, go WOT at 3000 rpm to 6500rpm to 7000 rpm while monitoring your boost guage and your knock at the same time to make sure everything is looking good.(please be careful, be safe; do not do this in busy public roads, make sure the road you are on is clear of obsticles/people/traffic since you will be watching your guages at the same time to make sure boost and knock are in check)

I always tune by knock, because knock and airflow(mostly) is going to be determining your final timing anyway. There are other variables like coolant temp and intake temps that will also affect your final timing but I would not worry about those now.

Look at your timing graph along with knock, if you see 1 - 3 counts of knock, I would not worry too much about that. If you see high counts of knock above 10 counts, then monitor your A/F ratio around that rpm(do not pay attention to stock 02 sensor, it is useless in open loop), and first try to increase your fuel to see if that will resolve your problem, in most cases it would, if it does not then car is knocking because you are running too much timing for the gas you are using, I would either increase the octane or manually pull the timing or run less boost. Once you run your car smoothly at low boost, increase the boost to say 15 psi, make small changes. Repeat the above procedure. Also give your car to cool down between runs if you have a small IC, it may heat soak, and that may also result in knock.

Take a note if your A/F ratio reflected your change in fuel, if it did not, then you may have a fuel delivery problem somewhere, it may be insuffecient pump, not enough voltage to pump, injector problem, FPR may not be raising 1:1 with your intake pressure, or there is a blockage somewhere in the fuel line(not likely).

Tuning is very simple if you have the right tools, and good running car.

 

[ninety7gst]

well the car came w/ the aftermarket turbo...i put in bigger injectors and afc and such myself, and i didn't know what else to correct..thats y i came and asked questions...not 2 get yelled at by angry people, but to get questions answered. i didn't put the turbo in, someone else did before i bought it...granted i bought the car knowing it had an aftermarket turbo....but still calm down before u have a heart attack

 

[Batty200]

My post wasnt meant to be imflamatory. Well it was to a degree. People always try to pass the buck on parts. A 50trim is a known good turbo and its effects are well documented so if your results are bad then it is SOMETHING ELSE. People always blame their turbos or blame whatecer and then they buy something else and still have the same problem. That is a bad way to waste money. Figure out what the rel problem is and correct for it.


Later