"stage 2" VF40 to VF52, stock fuel.

[scoobydoobie]

So after reading a bit, it seems a pump upgrade is recommended for safety/tuning issues when upgrading to a VF52?

[bigjweb]

i went stage 2 with a BNR 16g turbo, FMIC, DW fuel pump, GoFastBits Manual boost control. Intake, pro road tune and up and down pipe and stock exhaust, just about 325, i could go for more but dont want to risk blowing the 5eat till i do the valve body upgrade.

 

Just out of curiosity, why'd you go with a manual boost controller over a 3port?

With all the 3ports available relatively cheap, I wonder why people still use the manual controllers

[spc2125]

Theres actually a vf52 for sale.

Get a tmic/ grimmspeed ebcs/ dw65c fuel pump/ oil supply line with oil filter from infamous and you can make some serious power.

 

Regarding the turbo oulet, they rip easily so if you dont rip it when installing the new one then dont worry about getting one, but be prepared.

 

Heres my mod list with the vf52

Vf52 Turbo*

Perrin TMIC

TGV Delete

Dw65C fuel pump

Gimmick Turbo Inlet

CNT Catless Downpipe*

Indivia Catless Up Pipe

*Magnaflow Cat Back*

Grimspeed 3 Port Boost Solenoid

Forge BPV

 

Making 325whp

 

Its a lot of fun, just dont into trouble with it

[bigjweb]

As a general rule of thumb your wastegate actuator should be able to hold boost pressure to about double what it's opening pressure is. IOW, if you a stock 10psi actuator it should be able to hold about 20psi. The problem is that on turbos with restrictive hotsides (small turbines or exhaust housings) you can easily run the turbine close to it's choke point during spool or approaching peak revs. Very high exhaust gas backpressure will 'help' the actuator bleed boost off by pushing on the gate. IOW you might have bled much of the boost pressure away from the actuator via the restrictor pill and solenoid, but boost won't rise any further because EGBP is pushing the wastegate open.

 

I've read about the double boost pressure rule before. Does this apply more as the engine gets closer to redline? And hold more true as a turbo increases in size?

 

The reason I ask is because I was able to hold 22psi with the stock VF40 actuator, but not as much to redline as a 1bar actuator. mweiner actually argued with me about not needing an upgraded actuator at my elevation (5280'). I tried explaining to him that the little actuator, having a small spring, just can't physically stay shut as the exhaust gasses pass by. However, after reading the double psi rule over and over, I wonder if other factors play into the accurateness of that rule since I was able to run more boost then 2.5 times the stock spring pressure (with an HTA68 on e85).

[fahr_side]

I've read about the double boost pressure rule before. Does this apply more as the engine gets closer to redline? And hold more true as a turbo increases in size?

 

The reason I ask is because I was able to hold 22psi with the stock VF40 actuator, but not as much to redline as a 1bar actuator. mweiner actually argued with me about not needing an upgraded actuator at my elevation (5280'). I tried explaining to him that the little actuator, having a small spring, just can't physically stay shut as the exhaust gasses pass by. However, after reading the double psi rule over and over, I wonder if other factors play into the accurateness of that rule since I was able to run more boost then 2.5 times the stock spring pressure (with an HTA68 on e85).

 

I believe there is quite a tolerance range on the non-adjustable OEM actuators as to their operating pressure. I've tested supposedly identical parts, some of which opened at 9psi and some as high as 11psi. Double actuator pressure is a rule of thumb, it's not carved in stone.

 

If you look at EGBP through a pull there is a hump during spool where exhaust flow spikes but turbine speed is low. Pressure has to rise in order to overcome the turbo's inertia. EGBP then falls as the turbo passes through it's efficiency sweet spot, only to rise again in the upper midrange. If you log WGDC that will roughly mirror EGBP.

On smaller turbos, or those with hotside flow a bit small compared to the compressor, you'll then see a steep rise in EGBP as you approach redline.

This I believe is more about the match between hot and cold side flow than absolute sizing. People going to larger turbos seem less willing to hobble them them too-small exhaust housings

[BigTDogg MA]

This might help. the 52 car had a stock tmic fwiw. Sea level cool air 93octE10 blah blah blah

 

 

http://www.brentuning.com/dyno/graph.php?gb=0&hp=1&torque=1&rpm=1&sl=1&sln=1&sat=0&cb=0&dgr=1&smm=0&sg=1&runid1=25&rgb1=&runid2=15&rgb2=

 

AWHP? I assume a roller dyno or is this a Mustang style?

 

I found this thread searching for info/opinions on the combination of a VF52 and TGV deletes. The purpose of the TGV is to more evenly mix air and fuel for better MPG, is that right? So deleting them is strictly for performance reasons? My mech said that "the vf52 typically comes very close to the rear TGV" so I assume it's a tight fit?

 

If they don't fail, and actually give better MPG, then I'm probably going to leave them be.

 

Thoughts?

[spc2125]

I had to do a TGV delete when my mech installed the vf52. He said it might have been because of the invidia uppipe. I wish I didnt have to do it because it doesnt really gain anything, just really had to do it for clearance.

[Nrw]

AWHP? I assume a roller dyno or is this a Mustang style?

 

I found this thread searching for info/opinions on the combination of a VF52 and TGV deletes. The purpose of the TGV is to more evenly mix air and fuel for better MPG, is that right? So deleting them is strictly for performance reasons? My mech said that "the vf52 typically comes very close to the rear TGV" so I assume it's a tight fit?

 

If they don't fail, and actually give better MPG, then I'm probably going to leave them be.

 

Thoughts?

 

Dynapac, stock 5mt lgts put down 190-200 depending on health. I wouldn't go out of my way to do deletes, gains are hardly noticeable. I've heard of some people needing to delete them for clearance, others no problem.

[lee07]

Did my tgv because of the check engine light was coming on every month

 

Put the grimmspeed 8mm spacer on and it seems to help stay cooler then before but I just did it to get rid of the "Check engine"

 

Not sure about better gas mileage but I get 22-23mpg on E85

[BigTDogg MA]

I'll see if he can leave them in. I don't want to buy deletes if I don't HAVE to. I didn't want to replace the turbo either, but I'm not wagering my engine.

[Nrw]

FWIW most of them we see come in still have them. I plan on keeping mine when I get around to buying a vf52

[spc2125]

I'll see if he can leave them in. I don't want to buy deletes if I don't HAVE to. I didn't want to replace the turbo either, but I'm not wagering my engine.

 

You dont necessarily have to buy them. You can do a sort of "ghetto" delete. Im not too familiar with the whole process but you can just leave some rod in there I think Because I remember I didnt have to buy mine.

[Nolmers06LGT]

You dont necessarily have to buy them. You can do a sort of "ghetto" delete. Im not too familiar with the whole process but you can just leave some rod in there I think Because I remember I didnt have to buy mine.

 

No.. You pull the rods, grind everything down, and seal with JB Weld.

[Sbui]

I'm planning to do this project next week here is my list of mods new vf52, Cobb intake, full cobb catless turbo back,cobb bpv,Perrin tmic, Perrin inlet, iNvidia down pipe, gtspec uel header and up pipe, warbro255 fuel pump, and a wideband o2 sensor.....

Hopefully it turn out good oh yea I'm getting a Street tune, I would like to put it on a Dyno but beside all this I just got some rce Tarmac and doing the dual din navi set up way to much $$$ I'm putting in the car all at once

[Cone_Killer]

Just a heads up, due to the boost creep issues of the VF52 (actually all large VF's) you may run into needing more fuel or an EWG. I opted to go with larger injectors with my 52.

[Sbui]

Just a heads up, due to the boost creep issues of the VF52 (actually all large VF's) you may run into needing more fuel or an EWG. I opted to go with larger injectors with my 52.

 

So wait I need bigger injector too?

[Cone_Killer]

Not necessarily. Some people may experience boost creep more than others. Its just something to be aware of when doing an upgrade like this.

[BigTDogg MA]

You dont necessarily have to buy them. You can do a sort of "ghetto" delete. Im not too familiar with the whole process but you can just leave some rod in there I think Because I remember I didnt have to buy mine.

 

I appreciate the heads up, but I don't do ghetto on any of my cars.

 

Regarding fuel and boost creep. Would a 3-port EBCS help with that? I'm running a Cobb downpipe (bellmouth) so I wouldn't anticipate that causing any creep issues. Typically I've seen creep more with divorced style downpipes.

 

So the interference is with the motor outside the TGV which actuates them?

 

Does the delete improve MPG or is strictly a performance oriented improvement? You'd think more flow = less resistance and better MPG (like UP and DP), but what was the purpose of the TGVs in the first place, fuel economy right?

[Cone_Killer]

I appreciate the heads up, but I don't do ghetto on any of my cars.

 

Regarding fuel and boost creep. Would a 3-port EBCS help with that? I'm running a Cobb downpipe (bellmouth) so I wouldn't anticipate that causing any creep issues. Typically I've seen creep more with divorced style downpipes.

 

So the interference is with the motor outside the TGV which actuates them?

 

Does the delete improve MPG or is strictly a performance oriented improvement? You'd think more flow = less resistance and better MPG (like UP and DP), but what was the purpose of the TGVs in the first place, fuel economy right?

 

Unfortunately, a 3 port won't help. I am running the largest downpipe made (TXS 4") and it is creeping pretty badly so DP shouldn't be a factor either. In order to counter the creep you would need to run either an external wastegate to eliminate the issue or upgrade the fuel system to compensate for it. In my case, I was hitting 10psi creeping to 16ish on 0% wastegate duty cycle with my injectors were hitting 110% duty cycle at the same time (all on a base map ). I decided to do injectors for added safty rather than control the boost and max out my injectors early. In reality, I should be doing both but I'm poor.

 

Having said all of that, you may not even have an issue like this. Lots of people have been fine on stock fueling.

[fahr_side]

I am running the largest downpipe made (TXS 4") and it is creeping pretty badly so DP shouldn't be a factor either.

Um, maybe it's the size of the downpipe that's exacerbating your creep problem. Lower resistance in the DP is lower pressure post-turbine, which is more pressure drop across the turbine. Since that's what spins the wheel...

[Nrw]

Um, maybe it's the size of the downpipe that's exacerbating your creep problem. Lower resistance in the DP is lower pressure post-turbine, which is more pressure drop across the turbine. Since that's what spins the wheel...

 

This, I know on some platforms a catless downpipe will create boost creep. Welding in a cat solves it. I haven't really heard of 52's having a tendency to creep.

[cryo]

I have seen the majority of vf52's be fine with stock fueling but some end up creeping to an unsafe level. There are a million threads on nabisco about it since its a common stage 2 problem for them. Some have cured the issue by installing a catted dp like mentioned above, fahr side hit the nail on the head on the reasons why.

 

Its uncommon but does happen and you normally have 4 choices but some will be guaranteed to help where some are a possible option.

 

1. Install ewg to eliminate the creep guaranteed

 

2. Install injectors and supply enough fuel for the creep as long as its moderate and tune for it.

 

3. Install catted downpipe- no guarantees but helps some and doesnt help others depending on the severity. * some creep to 22-24psi by 4500rpms and 0% wgdc!*

 

4. Have the turbo professionally ported as this seems to help *i have yet to see a professionally ported vf52 have issues with creep, keep in mind if you port it on your own and screw it up you end up with a worthless turbo*

 

Obviously this is just my opinion based on my experiences as i have tuned quite a few vf52's on many subaru platforms.

 

Hope this is helpful

 

Dave

[BigTDogg MA]

Thanks guys. My engine has 141K on it now, so I'm not going to be maxing out my stock fuel system and pushing this bitch too hard.

 

My DP is catted, and I really don't plan on running more boost than I could get away with 85% duty cycle or so on my stock injectors.

[spc2125]

I appreciate the heads up, but I don't do ghetto on any of my cars.

 

 

Not ghetto by all means. That was the wrong choice of words.

[fahr_side]

My DP is catted, and I really don't plan on running more boost than I could get away with 85% duty cycle or so on my stock injectors.

 

I think you're being overly conservative. As long as the injectors are supported with enough pump, they're quite happy even at 96 or 97%. The problems come when the pump cannot maintain a full 3bar above manifold pressure or when you tune to such an IDC in air that isn't the coldest / densest day of the year.