Been driving the car around lately and now that I'm gettin use to it, I've noticed that its not spooling til around 4500 RPM. That's not the interesting part though, the car doesn't *act* like its getting boost til about 5000 RPM. Here's the setup:

stock B18C5 bottom end (10.6:1 compression)
Hondata 3B
2.25" exhaust, 2.5" downpipe
Tial wastegate, GReddy Type S BOV (I'm replacing it with a 1G DSM BOV)
T3/T4B turbo, I don't know the A/R however
The guy I bought the turbo from (its just been rebuilt, looks brand new, never been used) said in old form it hit full boost at 3500 RPM on his LS Integra. I don't see how he could have re-trimmed it so its not boosting until 1500 RPM's later. Any ideas? I haven't gone to the dyno but I'm *SURE* the car is running really rich. I think its just tuning, but I dont know. Any help would be appreciated. Thanks, Todd.

 

Well, if you're sure it's running rich, it would bog/lag like you described. That happened to mine when my FMU crapped out and started dumping fuel in. At low speeds and rpms, it would nearly stall out....but as soon as it hit around 4500-5000 it would suddenly shove you back in your seat when I guess the fuel mixture was good.

Try looking at your fuel system somewhere.

 

I cant add to your question. But I have one for you. Why are you replacing the Type-S bov with a 1G DSM one? Just curious cause I have one (dsm) and thought it was a cheap alternative to the aftermarket ones.

 

Keep in mind that the LS motor has a much better volumetric efficiency at lower RPMS when compared to the B18C5 this will allow for better spool times

but it sounds like you have a tuning issue more than anything.. You may be experiencing a lean condition until 4500 and then you have the fuel necessary to make the torque to really move the car.. the other thing it may be is timing.. if you dont run enough timing the car will not make power. Be very cautious when advancing the timing.. overzealous timing can easily break a piston. or blow a head gasket. hth

jason

 

hmmm could be some tuning factors. you have a 2.5 exhaust? you still got the cat on that muthafucka? at least get your exhaust upgraded to 2.5, if not 3. once you "eliminate" the cat problem you will notice the turbo spool at 2000+rpms.

 

There are a ton of things that can cause a real laggy setup.

1.) You have a B18C5... what trim is that T04B? It could be that the compressor characteristics can be working against your motor's characteristics. In other words, your engine's curve on the compressor map for your T04B could be off to the left of the surge line.. which can cause major lag.

2.) If you're running really rich.. and I mean REALLY rich, yes the car will feel sluggish.

3.) Your exhaust is restricting the turbo for sure. 2.25" for your turbo is like you suckin up McDonald's milk shake with a coffee stir-straw. Go atleast 2.5"

4.) Could just be bad tuning with the Hondata.. I'm no expert on this subject, nor do I have any experience. :-/

Whatever it is, I hope you find out soon! Good luck!

EDIT:

I just read that you dont know the trim of the turbo.. I'd definitely try and find that out however you can.



[Modified by Rob92SC, 11:47 PM 2/17/2002]

 

Look for a wastegate leak.

 

I'm not seeing much in the way of any leaks. I'm running a test pipe (OBDI conversion) and I'm going to make some calls tomorrow to find out what trim and AR I have for the wheel. I thought that stuff was usually stamped into the compressor/exhaust housing, but I couldn't see anything. I'm also going to take the midpipe off to see if my exhaust is really restricting things (I'm sure it is, but its gonna take some cash to get a 3" downpipe, test pipe, and exhaust ). The only real "tuning" i can do is via my FPR, when I lower the no-vac pressure to about 43, the car seems to hesitate at high RPM with no change in spool time. The only reason I'm thinking its tuning is because the turbo DOES spool before I notice any sort of power increase. I'll keep hunting, thanks for the suggestions! EV.

 

There is a feature called Antilag on some EMSs that retard the timing and lean out the mixture to hold a given RPM under WOT with the clutch disengaged.. this will also create a lot of heat to spool the turbo, and the car will build boost without moving. this is why I suggested a lean condition or not enough timing.

jason



[Modified by st00pid, 7:20 AM 2/18/2002]

 

Shouldn't you upgrade the cat and exhaust to at least 2.5inch. You're probably having to much back-pressure.

 

It sounds to me like you have an exhaust leak, a restrictive exhaust shouldn't even make that turbo spool up that late on your motor.

 

I'm going to take the "neck" off the wastegate and try it that way. I've got that little 90-degree thing to move the wastegate away from the head and I noticed on the one joint between the end of that neck and the W/G, there's a little black soot which tells me there's *some* type of leak there. Also one of those surfaces doesn't have a gasket, I'll try moving that tomorrow and see where it takes me. After that, its dyno time. Peace, EV.