Boost Surge and Engine Surge

[DSM_Nick]

I am a new member so figured this would be where to post, I also looked at some other threads but they weren't quite the same problem I am having. I have a 1992 Eagle Talon TSi.

The problem to me seems to be a type of surging of the car when acclerating. Probably the best way I can describe it. It only happens when I am accelerating or wide open throttle. The boost will get up to its normal 9psi about and then jump to 12, to 10, to 11, sometimes to 14. While it does this I can feel the car surge. It started doing this after I put on the AEM tru-boost gauge and boost controller. You have to set your wastegate spring pressure on the gauge and I think that could be it. Cause when I set the gauge to OFF and it runs the turbo on wastegate pressure it only boosts 9psi at most, but does this with no surging. This is not bov flutter, and pretty sure its not compressor surge. Definitely could use some input though and was wondering what the wastegate spring pressure is on an Evo III Big 16g. Because, I have the 16g on it now and it does it, it also did it when i had a 13b on the car. The only difference was it jumped at lower psi with the 13b that was stock.

 

[mitsu-luver]

you can get a after market bov but ## still going to have to reroute it to the intake. ive heard that some people don't and have no problems but i highly recommend u reroute as long as ## car is running a maf sensor. it should not flutter as long as you don't have any serious comp. surge problems. you should not have any surge!

 

[DSM_Nick]

Ok, hmmm. That would be a good idea, so would it even be worth the money to buy an aftermarket one that recirculates? Or just stick with the stock one? The only person I know that vents his and has no problems, is my friend with his talon. But he has a complete AEM stand alone that is probably tuned to compensate for that.

And no I am not having the same problem anymore. No surge now, and no flutter. The problem I was having was that my wastegate pressure was set to high on my gauge and electronic boost control. So because it was to high, my boost controller wasn't regulating boost until that point, which was too high. That made it surge and now it is perfect. Thanks

 

[blacksheep86]

I'm glad to hear you got the problem cleared up. Why do you want to get rid of the 1G BOV? It's one of the best BOV on the market under/around 30psi and it came on your car stock.

 

[DSM_Nick]

Thanks for that, I am glad as well. Very good point. I don't want to get rid of it, but I picked up a Tial blow off valve for free. These are awesome blow off valves and by no means cheap. So I was thinking about putting it on. That would be why I am asking

 

[blacksheep86]

Oh, ok, I understand now. So I assume it's a non recirculating BOV then? You can always give it a try and see. You'll probably run rich but all cars will act different to different mods. Some have no problems venting to the atmosphere and some do.

 

[DSM_Nick]

Yeah I know, it is a hard choice to make. But I might just have to try it and see. And there is probably no way to tune for letting out after - maf air on a dsm link is there? Cause that might help it, but not sure since I don't have my dsm link yet.

 

[blacksheep86]

Um idk I've never really looked to see if you could do something like that on mine. I guess I wouldn't really know where to begin looking (im still new to link). I'm not sure how 0% throttle tuning would work?

 

[DSM_Nick]

Yeah no idea's on that either. But I remember my friend telling me that you could somehow compensate for the air getting out with dsm link. Somehow it just adjusted your maf reading or something, but maybe he was wrong. I also took out this restrictive round piece on the back side of my maf going into my intake pipe. Not sure if that is good or not, heard it was good?

 

[blacksheep86]

I don't know what piece your talking about on behind the MAF. Also there probably is a way to tune it with dsmlink I just don't have very much experience with the software yet. Too much snow up here for me to mess with it right now.

 

[Bud92gsx]

Yeah no idea's on that either. But I remember my friend telling me that you could somehow compensate for the air getting out with dsm link. Somehow it just adjusted your maf reading or something, but maybe he was wrong. I also took out this restrictive round piece on the back side of my maf going into my intake pipe. Not sure if that is good or not, heard it was good?

A round peice out of the back of the MAF...WHat it this peice? You have a pic??

 

[DSM_Nick]

Yeah true. I will have to mess with it as well once I get one.

The round piece is the back of the maf and whole intake housing. I don't have a picture, but the best way to describe it is a round piece that is cut into triangular sections. Not sure what is does, but it comes out and it looks restrictive

 

[Bud92gsx]

I'll have to look and see if I can figure out what you are talking about. If you could get a pic, even on your cell phone that would be great..

 

[DSM_Nick]

I found a picture of it. The actual name of the piece is a silencer. And it is only on 1st gen's i guess. Heard it was restrictive and ok to take out though

 

[Bud92gsx]

Ahh nice to know I don't have that particular MAf..It goes Filter, maf, pipe.. Not that big canister looking thing...

 

[DSM_Nick]

Yeah, that is how pretty much all the 1g talons are it seems. Pretty restrictive and stupid. I modified a lot of it though. But oh well, just waiting to get an intake set up

 

[DSM_Nick]

Just would like to let everyone know that I solved the boost problem. With the AEM controller I have the car is now pushing 12 to 13 psi consistently. No surging, or spiking now. What I thought was "wastegate spring pressure" on the gauge was actually "spring crack pressure". So I had to lower that, and then I had to turn up my duty cycle for the gauge.

What would be a safe psi to boost on a stock engine though? Or like the max even for my engine? Cause I want to be really safe until I get it tuned

 

[Bud92gsx]

You will be fine running 12-13 psi daily, and not ruin anything.. You can even go 14 psi and call it a day... Especially in Colorado. When I lived in Laramie Wyoming this summer at 7200 feet I ran more than 14psi. You can try to compensate for the lack of air density at that altitude. But try it at 14 and see how the butt dyno feels...

There is a restrictive plate behind the left headlight held on by two 10mm or 8mm bolts, I can't remember for sure. Try removing thist.. Might help a smalll amount as well..

 

[DSM_Nick]

You will be fine running 12-13 psi daily, and not ruin anything.. You can even go 14 psi and call it a day... Especially in Colorado. When I lived in Laramie Wyoming this summer at 7200 feet I ran more than 14psi. You can try to compensate for the lack of air density at that altitude. But try it at 14 and see how the butt dyno feels...

There is a restrictive plate behind the left headlight held on by two 10mm or 8mm bolts, I can't remember for sure. Try removing thist.. Might help a smalll amount as well..

Ok, thanks a lot for that reply. I live in colorado, but I am actually going to school in wyoming. So I could run a little higher, but I have to be safe because it is not tuned for my 450cc injectors or the big 16g yet. So just want to be careful