i have a stock s5 turbo in a 85 se. i have straight 3" exhaust is the only mod. i think it is running lean already which worries me so i was planning on porting the wastegate and getting some bigger injectors but i cant decide how big. i'm new to spoolin. reason i think it is lean is cause the turbo is completely white inside.

how much psi does the stock wastegate flow before it opens?

how big of injectors would i need if i was going to port it? and eventually put on a front mount?

i'm not too worried about it running rich and a little shitty i just dont want to blow it up running it lean.

any advice would be much helpful thanks.

 

what do your leading plugs look like. That is a better way to determine fuel mixture.

 

Your better off asking turbo questions to the FC group. There are a bunch of 1st geners running turbos, but most of us run N/A. There will be more people there capable of answerng questions like wastegate flow and whatnot.

 

S4 and S5 turbos have different blow off pressures. Those psi's should be listed in the 2nd gen FAQs. Since you've gone to a full 3", your wastegate MUST be ported and adding a boost controller wouldn't hurt either. As it is now, you're over boosting and the engine is in danger of terminal overboosting.

You will find answers to all you questions in the 2nd gen section, but be forewarned, they aren't as friendly over there as we are here.

 

How would a boost controller help him from over-boosting? A boost controller can only raise boost.

 

Get a wideband!!!!!!!!!!!!!!!!!!!! If you wait to check plugs it can be too late. What fuel management are you running? How are you controlling the timing??

 

My error, I should have said wastegate.

 

i was running stock ecu i think. it says something racing corporation on it assumed it was stock. planning on running just safc if i can get by or rtek if not. i would post in the fc section but it seems their either dicks or give mis information.

 

A little more info on your setup is needed. If you are running a complete S5 setup (ecu, injectors, map, maf, etc), the 3" exhaust is going to kill that engine. If your not running a wideband, your asking for trouble. The only way you can get by is to make some restriction in the exhaust. The turbo should not be boosting over 8psi with the stock injectors.

 

yeah complete s5 stock. i was planning on running 720cc all around and porting the wastegate. for management i was going with an safc unless i'd need an rtek? like i said new to boost

 

Without the engine being ported, 720s on the primarys will be overkill. If you are having boost creep problems, don't throw more fuel at it to try and correct the problem.

 

no boost creep problems. so u think just secondaries 720? with a wastegate port?

 

Really? No boost creep running a 3" exhaust behind a stock S5 turbo? Are you even running a boost gauge? On a "stock" S5, the 550s can handle up to 10psi without leaning out too bad. 720s on the secondarys if your planning on pushing beyond 10psi. Stock 3 piece apex seals go bye bye about 14-15psi. Just ask me how I know.

 

if you have straight exhaust, just like everyone is saying, your wastegate MUST get ported. you have to be spiking if you do not have a cat, and therefore yes your are probably running lean. and just remember that in the case of fuel management the more money you spend now the more you will save later and you will much happier. i recommend that you get a boost gauge FOR SURE if you dont already have one and getting a wideband o2. this can save you an engine very easy. As far as engine management to each his own. i have megasquirt on my turbo fb(i would not recommend this for a beginning tuner) and Apexi Pfc on my FD(easy to use for the most part but not an FB application) so i would recommend you go browse the engine management sections and decide what is right for you as far as price and ease of installation. like it was stated before, dont fix your boost problem by adding more fuel, that is just asking for trouble. And for port sizing it all depends on what type of port and how aggressive and even then it can vary alot for your fuel. it for the most part should be done in a one off fashion. Your injector size will also vary by how much boost you want to run and ect. hope this helps a little

 

i do have a cat but i'm pretty sure the boost isn't spiking. it runs as normal as you could expect. when i said port it i only meant the wastegate i'm not porting the motor at all. i was gonna get an safc but heard u can't adjust the timing with it. but with an rtek isn't that a complete ecu?

 

so you have a cat? then it is not straight exhaust so that clears that up. do not remove the cat until you have the WG ported. so do you have a boost gauge?

 

no gauge. without the wastegate port what psi would i be in the range of?

 

my question is this. wouldn't i just leave the wastegate alone to run alot of psi and then get larger injectors and a fuel management system? my goal is to be around 260-280 hp. not sure if its even possible with stock turbo or stock intake/exhaust ports.

 

that is not a good idea. this is why i think, your wastegate is there to limit your boost at a point that you want reliably. if you set your boost to 15psi with a boost controller and a ported wastegate it will build fast to the psi and release as soon as you are off the throttle. the wastegate allows the exhaust gasses to flow past the turbo and therefore not spool it anymore when you dont want it/need it. If the wastegate isnt big enough to bypass the gasses when you dont want them the turbo will continue to spool more boost because the exhaust is moving so fast because there is no restriction. the boost will continue to rise and your engine will lean out and pop. if you just try to run off of a spike it will also not reliably be the same and it is the number one way to blow your motor. heres my advice. send out your turbo and maniflod to get ported and the turbo rebuilt. I used Rotaryshack and Robert did a great job for me. use whoever you want. Then get a boost controller and injectors and Fuel management. then you will want a FMIC and the problem is this is all expensive and will keep adding up when you need all these parts and your stock motor will not last that much longer depending on mileage. to answer your question, yes that should be an achievable power on stock ports but it will only last so long and you will need to add alot more parts. remember you will need money for tuning and making your fmic piping because this cant really be an out of the box part.

 

alright. i rebuilt the turbo already so thats cool but my flow is low so i'm gonna have to port it all myself. how big would i want to port the wastegate to achieve near or above the numbers i'm hoping? i'm gonna have to do this myself but since the wastegate can only be as large as the flapper around how much psi would it push if the gate was ported as large as it could be? near 12 psi or so? thanks for all your help i just want to get my car running right

 

Porting your wastegate isn't going to net you any power gains. It is just to help prevent you from overboosting.

S5 wastegate porting: http://fc3spro.com/TECH/HOWTO/KWG/kwg.html