Thoughts on my Turbo Upgrades

Paisan · Post by **Paisan** » Mon Sep 06, 2004 5:20 pm

113K miles on my '94 Legacy Sedan Turbo

I'm planning on putting on the following and would like to hear from some folks more knowledgeable than I on the viability or if you think I'll need anything else...

VF23 Turbo
V4 STi Intercooler
Bosal Downpipe
Custom DP back exhaust
VDO EGT, Boost, Oil Temp, Oil Pressure Gauges
MBC

There has been debate if I need to add in some kind of engine management such as a SAFCII or similar. What kind of reliable power do you think this setup will yield?

I've already done the suspension, tires and brake upgrades which I always believe in doing before adding power.

-mike

BAC5.2 · Post by **BAC5.2** » Mon Sep 06, 2004 9:28 pm

Sounds like a good idea. If you want to make a lot of power (or have the potential to), you should ditch the TMIC and go FMIC.

Get a good downpipe (CES for example), and that's about it.

You could safely make about 260 or so on the stock fuel system (in terms of total flow of the stock injectors).

What color is your car, by the way?

Paisan · Post by **Paisan** » Mon Sep 06, 2004 9:54 pm

Nah no FMIC for me, hate lag-mounts...

Also don't want to go too crazy i figure about 250 at the crank will be fine for me.

http://azpinstalls.com/miscpics/azp-05-15-04/index.html

Mine is maroon, pics in the link above

-mike

legacy92ej22t · Post by **legacy92ej22t** » Mon Sep 06, 2004 11:41 pm

Mmm, nice ride! Looks very good.

You're mod list sounds nice but if all you're looking for is 250 chp then IMO the VF23 is a bit of an overkill. You could achieve 250 chp with a TD04L out of a rex and get it for probably around a $100. Not only that but it'd most likely have really low miles on it.

You can actually achieve around 250 chp on the VF11 too but you'll have no high end. The VF11 can't hold more then 10-11 psi after 4800 rpm.

IMO, you're fine with stock engine management at 250 chp but you may (should) want to add a Walbro 255 FP to that list.

Paisan · Post by **Paisan** » Tue Sep 07, 2004 12:01 am

Well I have the VF23 already got it cheap and low miles. I have a TD04 around too so I might use one of them.

Fuel Pump is easy to drop in, not a problem.

I figure 250-280, it is my daily driver so I don't want to totally kill my gas milage.

-mike

heelhooker · Post by **heelhooker** » Tue Sep 07, 2004 11:29 am

for what it's worth...
stock injectors: 330cc/min
LHV gasoline: 44 MJ/kg
density gasoline: 780 kg/m^3
assume fuel conversion efficiency of .3

max mass flow rate fuel= (330)*(4)*(1/60)*(1/1000000)*(780)=0.017 kg/s

power=efficiency*LHV(fuel)*flow rate(fuel)=(0.3)*(44000)*(0.017)
=227kW

=304 hp

now, is that 330cc/min at 100% duty cycle? if so, I guess 300 hp would not be "safe" on the stock system. Is a 30% fuel conversion efficiency a reasonably assumption for this engine? I would guess it's in the ballpark.

legacy92ej22t · Post by **legacy92ej22t** » Tue Sep 07, 2004 12:26 pm

Aren't our stock injectors 380cc?

rsstiboy · Post by **rsstiboy** » Tue Sep 07, 2004 1:38 pm

Paisan wrote:Nah no FMIC for me, hate lag-mounts...

Also don't want to go too crazy i figure about 250 at the crank will be fine for me.

http://azpinstalls.com/miscpics/azp-05-15-04/index.html

Mine is maroon, pics in the link above

-mike

pfft, i get no lag, plus I'd rather have a intercooler than a interheater.

vrg3 · Post by **vrg3** » Tue Sep 07, 2004 2:26 pm

1) I don't believe that front-mounts are inherently laggy. The volume contained in any decent intercooler piping should be easily consumed by the engine in a small number of revolutions.

Of course, there are a lot of people out there without decent intercooler piping. Too many bends -- especially if they're not mandrel bends -- hurt flow. So do transitions between pipe and hose. If pipe is welded together from short pieces, it can be hard to avoid ending up with jags from the welds coming through the surface of the pipe and interfering with airflow.

2) I'd say turbocharged engines on boost are a good deal less efficient than 30%.

3) The stock injectors flow around 370cc according to the flow tests RC Engineering did for magnux, at 100% duty cycle.

Paisan · Post by **Paisan** » Tue Sep 07, 2004 3:46 pm

I also don't want to hack apart my car... So lets stick with TMICs that can be put in with my AC working for this discussion

-mike

heelhooker · Post by **heelhooker** » Tue Sep 07, 2004 11:30 pm

If stock injectors flow 370 cc/min at 100%, then 0.017 kg/s flow rate seems reasonable.

As long as fuel enrichment is not the main charge cooling mechanism (good intercooling, water injection, etc), and timing isn't backed off too much, efficiency at max output will be close to that of a n/a engine. I don't think ~30% is unrealistic based on literature I've seen. If charge temp is high, and timing is backed off due to knocking, of course efficiency will suffer.

Anyway, I plan to find out...

Paisan · Post by **Paisan** » Wed Sep 08, 2004 1:35 am

Cool a good friend sells water injection kits

-mike

shemoves · Post by **shemoves** » Sat Oct 21, 2006 12:51 am

Just reading through this searching for some answers and figured it was better to post in an old thread than start a new one.

Regarding the stock injectors, what is the most boost you would run a 16g with them-assuming most of the other related parts(walbro/em/fcd/IC) were upgraded.

Adam West · Post by **Adam West** » Fri Oct 27, 2006 5:09 am

Yeah, I'd like to know that too.

To the list...yes, FCD I've heard is a must.

But I'm still in the planning stage too.

Any consensus on clipped wheels? Thinking of adding that to my deadbolt order...

Splinter · Post by **Splinter** » Fri Oct 27, 2006 5:25 am

hate to drag this offtopic, but arent gasoline engines below 50% efficient?

I remember reading something about how almost half the power the engine makes is lost in the exhaust heat

Splinter · Post by **Splinter** » Fri Oct 27, 2006 5:26 am

Adam West wrote:Any consensus on clipped wheels? Thinking of adding that to my deadbolt order...

Clipped wheels = sacrificing bottom end for top end.

I wouldnt bother unless you are planning on rebuilding the valvetrain for a higher redline

Adam West · Post by **Adam West** » Fri Oct 27, 2006 5:19 pm

Hmmm. Is that the same as lowring spool time, i.e. time to boost aka turbo lag? I thought that was the beni of clipping wheels? And if that was true then you'd be sacreficing top end for bottom end. What think?

Post by **Legacy777** » Fri Oct 27, 2006 6:09 pm

Splinter wrote:
Adam West wrote:Any consensus on clipped wheels? Thinking of adding that to my deadbolt order...
Clipped wheels = sacrificing bottom end for top end.

I wouldnt bother unless you are planning on rebuilding the valvetrain for a higher redline

This is one of those common internet folklore things.

If you want to know the real scoop talk to a vendor or shop that deals with turbos a lot. Deadbolt would qualify as one of those shops.

The main thing clipping helps with is overboost at higher rpms. Depending on the setup, it can also aid in spool up by allowing the engine to breathe with less restriction.

Like I said, if you have questions, call and talk with Jerry.

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Thoughts on my Turbo Upgrades

Thoughts on my Turbo Upgrades