HUGE increase in boost after FP 17PSI actuator install...is this safe??

[Rice Over Wheat]

Hey guys, I just installed a FP 17psi actuator. My AGP Big T28 was using the original stock actuator up to this point and I was previously running 15psi. The dyno #s in my profile are with that configuration. At open throttle I would spike to 18psi, then bleed off quickly to 14 ~ 15.

I removed the stock actuator and could pull out on the shaft quite easily. I think it was very worn. The FP 17psi actuator's shaft can't be pulled out by hand at all. After the bolt on replacement, I took the car out for a test run and there is a HUGE difference! The boost quickly hits 25psi now and stays there rock solid not wavering even a single millimeter throughout the band, the car pulling like a mofo now.

BUT I'm worried that it isn't safe to be running my car at this setting based on my previous tune. I gained about 10psi in boost over the stock actuator which is just insane and I do not want to blow my engine or turbo or whatever. What is your advice for what I should do now? Thanks!

 

[jwahl425]

does that actuator have an adjustable arm? (a nut that can be tightened or loosened) if so mess with that until you get the boost down, otherwise just re-tune the car

just looked at your mod list, are you using the stock injectors? if so you will DEFINATELY lean out even with the 255 Walboro at 25PSI, I would reccommend finding a way to turn down the boost somehow before you break something.

 

[elfroggo]

Boost Controller?

 

[Rice Over Wheat]

does that actuator have an adjustable arm? (a nut that can be tightened or loosened) if so mess with that until you get the boost down, otherwise just re-tune the car

just looked at your mod list, are you using the stock injectors? if so you will DEFINATELY lean out even with the 255 Walboro at 25PSI, I would reccommend finding a way to turn down the boost somehow before you break something.

Yes it has an adjustable arm with threads and a nut. I basically just removed the stock one and bolted up the new one, assuming that the length of the arm are the same.

See this is why I don't do my own work usually, as I am not 100% clear on how the actuator works. Do I want to shorten the arm or lengthen the arm?

And what is the danger of running at the current boost levels? I thought my 1G BOV wouldn't be able to hold these pressures like this. I definately need a re-tune though I'm sure...I have no idea how lean/rich I am running.

I tell you what though, this $100 bolt on part is the biggest bang for the buck for people running T25 or T28s.

 

[jwahl425]

good point^, are you using a Boost controller?
the dangers of running this boost level are:
massive counts of knock -> FMIC, Bigger Injectors, HIGHER OCTANE
Inernal Damage: the dreaded Crank Walk, Higher boost will Dramatically quicken crankwalk in your 7Bolt 2G, running lean for too long can also damage the stock pistons. ->turn down the boost or build up your engine
leaking BOV would only cause you to run richer so right now I wouldn't even worry about that since you need all the fuel you can for that PSI

 

[Rice Over Wheat]

just looked at your mod list, are you using the stock injectors? if so you will DEFINATELY lean out even with the 255 Walboro at 25PSI, I would reccommend finding a way to turn down the boost somehow before you break something.

Yes I am still on stock injectors. Are you saying I need to get 550 or 650 injectors now asap?

Yes I am using a mbc...I could dial it back but I don't like to mess with it without a dyno. What if I just stay off the throttle until I can find a dyno in town this week and someone to tune my car?

Btw, untuned I was running rich and my SAFC setting are now at -5% fuel after tuning. Maybe I should reset to 0 across the board.

 

[jwahl425]

What if I just stay off the throttle until I can find a dyno in town this week and someone to tune my car?

probably the best thing you could do period, if you connect a line from the outlet of the J-Pipe to the actuator you won't run anything higher then the PSI spring rate of the actuator, check FP's site and see, if it's too much of a difference then 25PSI you might just wait till you get it tuned but be warned, everytime you push the pedal just think about your engine going to s***, that should keep you from boosting.
just go get it tuned at 18-20 PSI with 550's should be fine, the SAFC can tune that easily.

 

[donmagicjuan]

If you change your actuator spring pressure without adjusting your MBC setting, your boost should change by the same amount as the difference in actuator pressures. Your previous tune was for whatever boost you were running before (15 psi?), not the MBC setting. If you don't want to retune the car, I would definitely suggest lowering the boost until you're as close to the original setting as possible.

And yes, 25 psi is more than likely pissing off your stock injectors. If you have a logger you can confirm this.

 

[Rice Over Wheat]

I REALLY appreciate the advice guys, I'm regretting I did this mod now.

I'll order some new injectors tonight to take care of this. This may be stupid to ask, but will my ECU compensate with the larger injectors after swap out. Meaning, will just upgrading to bigger injectors help me run richer as soon as they are swapped in? [edit: answered my own question]

Noob question: knock = lean, but how does knock feel like? I've never experienced this.

Yes, I will not be boosting over 15psi until I get a retune.

 

[Rice Over Wheat]

Ok, I checkout ot RRE's website and according to their chart:

http://www.roadraceengineering.com/eclfuel.htm

...at 25psi on 93 octane I should be running 660s or 550s with high pressure. So I will order some 650s.

Edit: I called FP and talked to them about my situation and their actuator. He said that I could turn down the mbc or just stay off WOT while I commute around town. I ordered their 550 injectors which he recommended over the 660s because of sacrifice in ride quality. So in two days I'll pop those in and he said with my old SAFC settings I should be mostly good to go as everything will richen across the spectrum. Then all I need is a re-tune to find the optimum settings.

He said that running 20 to 25 lb boost on my setup I'll easily push over 300 whp, which has been my goal, so that'll make me happy. Then all I need is a fmic.

Thanks again for the FAST advice everyone, it potentially saved my ride!

 

[jwahl425]

no problem, have fun w/all that HP!

 

[daren_p]

Do you have a logger? If not turn that boost back down with the MBC ASAP, as you are more then likely knocking like crazy & can do major damage to the motor. Main problem is lack of fuel with those stock injectors & heat soak with the stock IC. Without a logger I'd turn your boost back down to 15 until you get one. If you turned your mbc all the way down and the boost still isn't low enough, you will have to lengthen the actuator. Don't waste your time with the 550's, go with the 650's as this is the size you will be limited to with the SAFC (because of the timing advance you get by compensating with SAFC).

 

[Rice Over Wheat]

Well I already ordered the 550s on express delivery so it's too late to go bigger. They were only $260, so no big deal. I'll upgrade again later when i get a larger turbo.

I dont have a logger, however I just wont boost over 15psi while commuting to class and work. I shouldn't have any problems as long as I keep my lead foot on a leash for the next few days. Friday I will be heading to a dyno for a re-tune on the new injectors. Then I'd like to keep the boost 20 ~ 25 to get closer to maxing the T28.

 

[oldman]

I'm confused.

1. What psi do you get if you bypass the mbc?

2. What was the purpose of the 17psi actuator when your stock injector maxes out at around 16psi?

3. Please get yourself a logger.

4. I will not comment on FP's comments without knowing the full context but you will not be running 25psi for many reasons, most notibly 550s and stock sidemount.

What happen to your "professional mechanics"? Perhap learning things from ground up isn't such a bad idea after all.

 

[Ricardo]

Kevin, you should dial the boost controller all the way back until you get your injectors in. If this is done properly you should be reaching 17psi all across the board. To ensure safety, it is also a good idea to set your AFC all to 0 as you have more air going in now than before you don't want to run as lean as you were when you did the dyno tune at 15psi or less.

If this is done, you should be safe.

Once you get injectors you can give it more boost and I'm sure the car will pull a lot harder-- especially when u get a larger intercooler to cool all that air. As for injectors, I would recommend 550's if you plan on staying with the t28. 660's only if u plan going bigger later, like a 50trim or something similar.

 

[Ricardo]

and yes, you can just take it easy on the throttle for now.

 

[Rice Over Wheat]

I'm confused.

1. What psi do you get if you bypass the mbc?

2. What was the purpose of the 17psi actuator when your stock injector maxes out at around 16psi?

3. Please get yourself a logger.

4. I will not comment on FP's comments without knowing the full context but you will not be running 25psi for many reasons, most notibly 550s and stock sidemount.

What happen to your "professional mechanics"? Perhap learning things from ground up isn't such a bad idea after all.

1. Bypass mbc should drop boost to 17psi thanks to the new actuator.

2. The AGP Big T28 is a rebuild on the stock T25 housing. It was using the same T25 actuator from stock which is rated for 11psi. The stock actuator was preventing me from holding high levels of boost because it would spike at anything over 15 and drop quickly under to 13 ~ 15 on WOT. It may have been worse than stock because the arm was easy to pull out so it may have been shot.

It's not like I intended for my boost to spike this much. I was aiming for 17psi on stock injectors. I never expected to break 20 let alone hit 25.

3. This is where I pay others to tune for me. Too busy and too risky to do the tuning myself.

4. It holds 25 already and solid. Though obviously it wont be optimum there. Wherever it tunes best will be fine...I'll update when I find out this week. Btw, FP says 25 is the limit on 93 octane, while RRE says they recommend 660s with 25psi OR 550s with high pressure (walbro 255). I should be fine for my applications. For my engine's sake I will be looking for 20 though.

As for professional mechanics, today is exactly why I prefer shops do my work for me. Notice this happened because I decided to do a simple bolt-on myself, and it's not like there's a lot of literature on the forums about this part. There is nothing wrong with paying for warrantied work if you have the $ to blow. And I do. In hindsight, I should have had a tuner shop install and tune my car for me. Which is what I will be doing on Friday with the new injectors -- seeing that no regular shop will touch aftermarket injectors around here for liability reasons.

If that makes me a DSM owner rather than a DSMer, so be it. To each his own.

 

[Rice Over Wheat]

Kevin, you should dial the boost controller all the way back until you get your injectors in. If this is done properly you should be reaching 17psi all across the board. To ensure safety, it is also a good idea to set your AFC all to 0 as you have more air going in now than before you don't want to run as lean as you were when you did the dyno tune at 15psi or less.

If this is done, you should be safe.

Once you get injectors you can give it more boost and I'm sure the car will pull a lot harder-- especially when u get a larger intercooler to cool all that air. As for injectors, I would recommend 550's if you plan on staying with the t28. 660's only if u plan going bigger later, like a 50trim or something similar.

This is along the lines that FP was recommending as well. You know all the mods on this car and how it was running before, so this only confirms the advice. Thanks...I also thought resetting my SAFC would be wise. I'll do that.

 

[oldman]

You know all the mods on this car and how it was running before, so this only confirms the advice.

I feel that this comment was directed toward me so I'll repeat myself again, you will not be able to run safely with 550s and SMIC with a T28 @ 25psi on pump. Don't take my teasing so seriously.

 

[zippyshoe]

Just to give you an idea - I am running a FP Big28 at only 17psi with 660cc injectors, and I am already reaching a maximum injector duty cycle of 75%. At 25psi of boost, with 550cc injectors, you will probably risk running lean due to maxing-out your injectors.

 

[siceclipse]

after listening to Bruce bi*** for the past year on the correct way to install a MBC, i decided to change mine from the manifold to the pressure source located on the T-28


Right after i noticed that my WG was blowing the #### open

So now im gonna take my Original Hahn Racecraft adjustable WG out of storrage and hook that up.

 

[oldman]

after listening to Bruce bi*** for the past year on the correct way to install a MBC, i decided to change mine from the manifold to the pressure source located on the T-28

Please keep it clean, we got women and children in here.

Right after i noticed that my WG was blowing the #### open

If you're making this determination because boost dropped after you switch from manifold to compressor with every else being the same including mbc adjustments, you have boost leaks. Don't blame the actuator, if the actuator is the problem, it would have been blown open either way.

 

[donmagicjuan]

There is nothing wrong with paying for warrantied work if you have the $ to blow. And I do.

Do you have the money to blow on a road trip to Seattle? Then you can blow some more to have me tune your car. I'll even warranty it!

 

[siceclipse]

Bruce:

I do have a small leak at the TB shaft, but would that really make me drop from 22-15psi starting at 4500RPM?

I really thought it would have been from the direct boost source blowing open the weak wastegate.

 

[Rice Over Wheat]

I feel that this comment was directed toward me so I'll repeat myself again, you will not be able to run safely with 550s and SMIC with a T28 @ 25psi on pump. Don't take my teasing so seriously.

I wasn't offended. I was talking to Ricardo as he was the previous owner of my car and quite knowledgable about such things...former mechanical engineering student I believe. He was recommending much the same things as FP so I thought that was a good sign. The FP guy doesn't know my setup but Ricardo does.

Btw, I agree with you. Those numbers by FP and RRE were based on supporting mods of course. I'm not quite that ignorant to run 25 psi on my stock sidemount.

Oh and I ended up going with 660s because FP was sold out on 550s. They'll be here wednesday, so I ended up going the largest injectors my SAFC can handle.