Boost keeps building

[90mitsu3clipse]

I just bought a big 16g from forced performance, I have a manual boost controller. When I set the boost around 11-16 or what ever I set it at it still raises above 20. What causes that>?

 

[JayRolla]

I looked at your mods and it says you have a 3" exhaust. You have what is called boost creep. Search and you will find ways to fix it.

When your exhaust is high flow like yours it doesnt allow the flapper in the turbo to work right and will cause boost to never stop.

Ways to fix it.
1. Run 2.5" exhaust
2. Port the turbo correctly around the waste gate flapper.
3. Run external wastegate.

Im running 3" exhaust with no problem. My turbo was ported by slowboy along with my mani and o2 housing. Holds 9psi solid if I want it too.

 

[90mitsu3clipse]

It wasnt doing that with my stock turbo. It held boost fine.. It knocks also when I run 93 octane. When I run 105 by VP, it doesnt knock at all. I can run 22 psi and no knock. I cant afford to run that type of fuel all the time so, would a set of 550's and a 190 hopefully fix that?

 

[MadScientist92]

It's a habit of the big16g to boost creep. That's why your stock turbo did not do it. Search and there are ways to fix it as stated above. I believe there is even a tech article on it.

 

[90mitsu3clipse]

If I get the pump and injectors, would that be okay to run it with that much boost?

 

[Semprini]

It wasnt doing that with my stock turbo. It held boost fine.. It knocks also when I run 93 octane. When I run 105 by VP, it doesnt knock at all. I can run 22 psi and no knock. I cant afford to run that type of fuel all the time so, would a set of 550's and a 190 hopefully fix that?

lower your boost to 15 until you get a fuel system that can handle higher settings

 

[Semprini]

If I get the pump and injectors, would that be okay to run it with that much boost?

What are your goals?

Im pretty sure 550s and a 190 are enough for the 16g, but Im not sure about 22 psi. Youll also need something to control the larger injectors, eprom, safc ect.

 

[90mitsu3clipse]

they are low, it still spools up to 20-22 when I reach 4500rpms. I guess I need to stay out the gas until i get my fuel system.. Damn thats hard to do.

 

[Semprini]

they are low, it still spools up to 20-22 when I reach 4500rpms. I guess I need to stay out the gas until i get my fuel system.. Damn thats hard to do.

first thing is you need to get the boost creep under control.. you wont be able to tune your car proberly with boost problems. You need to get it to hold a constant psi. Search for porting and read up on it. Its not too hard just time consuming.

ps... itll be real easy to do if you pop something

 

[90mitsu3clipse]

ps... itll be real easy to do if you pop something

Pop something..? WTH.. Pop what?

 

[Semprini]

Pop something..? WTH.. Pop what?

ie break something...



not cherries this time



you have a logger.. are you showing any knock?

 

[90mitsu3clipse]

ie break something... ?

I know... I dont want to break anything..

you have a logger.. are you showing any knock?

Yea, I have a logger, thats how I know its knocking at 10+ psi.

 

[Eastwood95]

Get rid of that boost creep first, like stated before me, with your 3" exhaust the flow of air takes the path of least resistance, which is now your downpipe, and less air is escaping through your wastegate passage.

Just buying a fuel pump and injectors won't get rid of creep....

I know you're thinking "the car will hold more boost safely with those upgrades",
but you're trying to work around the problem and not fix it.

You need to get your o2 housing ported, or get a 2G o2 housing and port it, or buy a new one from a site like this: www.punishment-racing.com

Then you need to take your turbine housing and port the area around the wastegate flapper, making the hole bigger and making the flapper open as much as possible (90 degrees is optimal). I would suggest just purchasing a bigger flapper while doing this, and installing it while you're doing all the porting.

Link to get new 34mm flapper (at bottom of page)
http://www.teamrip.com/accessories.html

 

[90mitsu3clipse]

So, why does it knock starting at 10 psi with 93 octane but not with 105 from vp. I'm not giving it anymore fuel just higher octane..

Oh. and another ? Would a pump from an EVO provide enough fuel for the big 16g I have?

 

[c4uldr0n]

EVO pump would be sufficient for big 16g

 

[JayRolla]

So, why does it knock starting at 10 psi with 93 octane but not with 105 from vp. I'm not giving it anymore fuel just higher octane..

Oh. and another ? Would a pump from an EVO provide enough fuel for the big 16g I have?

You just answered your own question. Higher the octane the less chance you have at knocking. You dont have to adjust your a/f ratio. You would get more power if you did.

If you get the 190 and injectors you may beable to run 17-20psi max safely on 93. You still need a FMIC to run more and you would need race gas or meth injection to run 21+psi.

Now the best way to fix it is port the turbo. DO NOT INSTALL THE FLAPPER DOOR STATED ABOVE. This can cause the turbo not to hold high boost levels when you start to run it up there.

 

[90mitsu3clipse]

Thanks JayRolla

 

[JayRolla]

You may want to just remove the boost controller all together and see if it helps but Im guessing it wont. When I was running my 16g I would get knock at anything above 11psi on stock fuel system.

 

[Eastwood95]

Now the best way to fix it is port the turbo. DO NOT INSTALL THE FLAPPER DOOR STATED ABOVE. This can cause the turbo not to hold high boost levels when you start to run it up there.[/QUOTE]


So you think porting just the turbo will eliminate all creep?

 

[90mitsu3clipse]

You may want to just remove the boost controller all together and see if it helps but Im guessing it wont. When I was running my 16g I would get knock at anything above 11psi on stock fuel system.

I tried that first, it didnt work. What can I do to hopefully fix this problem without getting fuel management? If I go to 650cc wouldn't I need a regulator. Im on a very small budget, injectors and a pump would be about all I could get.. $260 for the injectors and $80 for the pump. Which injectors and pump would you guys recomend?

What about these? http://linux.forcedperformance.net/...ode=FP&Product_Code=FI&Category_Code=DSM-Fuel

http://linux.forcedperformance.net/...FP&Product_Code=GSS2xx&Category_Code=DSM-Fuel

 

[MaxPSITalon]

I ported mine just as the tech article "how to cure boost creep" describes. I tried to make my port work an EXACT replica of the pictures. I also put a 34mm flapper on. With my 3" exaust i can hold 10 psi to redline.

Good luck!

 

[kenamond]

First off, have you tried connecting a vaccuum line straight from the compressor outlet to the WGA? How high does it boost?

If it holds at ~9-10psi, then you may not have a creep problem. If this is the case, put your MBC back on, set it at its lowest boost level and make sure you still hold 9-10psi. Then start turning it up and doing test runs until it goes past 9-10psi. Then adjust to where you want it. On stock fuel and a b16g, watch your O2v when you get near 14-15psi. That's probably around where your stock fuel pump will max out. All cars are different, so be careful, check your logs, and make sure that you don't lean out and do major damage.

If it is creeping, getting supporting mods to handle what it creeps to is not a workaround. It's one of the 3 ways of addressing creep. However, you'd need a pump, injectors, and, at a minimum, SAFC piggyback unit to control the larger injectors.

Porting so that the flapper opens 90* is not necessary, as the WGA only has enough throw to open it about half way. If you're already porting, it won't hurt, though. Make sure you do both the O2 and turbine housings, put them together (no bolts) and make sure it still opens (sucks to find this out after the turbo's on the car).

However, you have a knock issue at 10psi, you need to figure this out before turning up the boost. I have the same problem, and nobody has been able to tell me why, so I can't help you. The long thread trying to figure it out is below.

http://www.dsmtuners.com/forums/showthread.php?t=235111&highlight=nitromethane

I've been wondering lately if lifter tick might be registering as knock and pulling timing. My tick has gotten worse lately, and I'd like to swap in revised lifters, but that's cash I'd rather spend elsewhere.

If nothing in that thread helps you, I'm out of ideas.

Just keep in mind that you may not have creep, and if you aren't going to run 20psi, you don't need fuel upgrades. Think about what's going on in the car. You only need more fuel than your stock system can provide when you're feeding too much air to the motor (higher boost).

 

[gdmbat85]

Heres my .02 cents on the topic. First off, you did your mods completely backwards. Not trying to insult you in any way, but you should have finished the supporting mods before you got that 16g. I'm sure your aware of this now. So here's what i recommend to correct the problem. First, you need a bigger pump (id recommend the 190lph one for you) and bigger injectors (550cc should be sufficient; make sure you get a controller). If you run high boosts without better fuel you'll wind up running too lean and burning your engine. The only thing stopping you from burning your engine right now is probably fuel cut, so make sure you dont let your turbo run high PSI's. Which brings us to how to control the boost levels. I recommend that you port out the section dividing the wastegate from the exhaust passage. it should look like this when you're done: http://www.roadraceengineering.com/parts/turbos/pte_turbo/pte_turbo_exhaust_outlet001.jpg
Its very simple to do, just get a dremel and a grinding bit. You could do the 34mm flapper mod as mentioned, however it doesn't sound like you have enough experience to do this on your own and it's going to cost some to have this done. Also, the bigger issue with the 34mm mod is that your turbo wont be able to get as high of a maximum boost level because that flapper wont be able to stay closed under the heavier loads it'll be experiencing.
To answer your question about the knock, higher octanes will result in less knock. This is because the higher the octane, the more evenly and fully the fuel will burn. Also, the octane number refers to the amount of compression needed for the fuel to combust - so the higher the octane, the less the chances are of your engine detonating because of that high pressure. This is exactly why high performance and turbo engines require premium fuel.

 

[kenamond]

Heres my .02 cents on the topic. First off, you did your mods completely backwards. Not trying to insult you in any way, but you should have finished the supporting mods before you got that 16g. I'm sure your aware of this now. So here's what i recommend to correct the problem. First, you need a bigger pump (id recommend the 190lph one for you) and bigger injectors (550cc should be sufficient; make sure you get a controller). If you run high boosts without better fuel you'll wind up running too lean and burning your engine. The only thing stopping you from burning your engine right now is probably fuel cut, so make sure you dont let your turbo run high PSI's. Which brings us to how to control the boost levels. I recommend that you port out the section dividing the wastegate from the exhaust passage. it should look like this when you're done: http://www.roadraceengineering.com/parts/turbos/pte_turbo/pte_turbo_exhaust_outlet001.jpg
Its very simple to do, just get a dremel and a grinding bit. You could do the 34mm flapper mod as mentioned, however it doesn't sound like you have enough experience to do this on your own and it's going to cost some to have this done. Also, the bigger issue with the 34mm mod is that your turbo wont be able to get as high of a maximum boost level because that flapper wont be able to stay closed under the heavier loads it'll be experiencing.
To answer your question about the knock, higher octanes will result in less knock. This is because the higher the octane, the more evenly and fully the fuel will burn. Also, the octane number refers to the amount of compression needed for the fuel to combust - so the higher the octane, the less the chances are of your engine detonating because of that high pressure. This is exactly why high performance and turbo engines require premium fuel.

I highly discourage ANYONE from doing the divided housing mod. Do a search on it at a minimum before you go destroying the turbine housing and decreasing the performance of your turbine. And I'd like to see how long it'd take someone to do that port job with a dremel and grinding bit. If you're going to try to fix the problem with porting, do as the others said, and read up on the porting articles.

If you can cure the creep, you can stick with your current configuration at whatever boost level your fuel system can stand without knocking. Upgrade from there.

If you can't cure the creep, you can port, get an external or O2 wastegate, or get supporting mods to run 20psi. The last option is fine if you can afford the required parts, and it won't require any porting or oversized flappers or hacking dividers.

 

[JayRolla]

PORT PORT PORT just port the damn turbo.

I tried that first, it didnt work. What can I do to hopefully fix this problem without getting fuel management? If I go to 650cc wouldn't I need a regulator. Im on a very small budget, injectors and a pump would be about all I could get.. $260 for the injectors and $80 for the pump. Which injectors and pump would you guys recomend?

No you would not need a AFPR for 650's. But you do need fuel management to run any larger injectors. Best bet would be port the turbo. Buy a 190lph because thats all you need with that turbo and this will not over run the stock FPR.

If you buy injectors you need atleast a SAFC and 650's would work great with that turbo.