What do you guys consider "living on the edge" in terms of boost....for 93 pump. I want to run 18psi which would put the car around 400whp, but I've had some problems getting the Tial springs to actually give me 18psi. Soooo I ordered springs that are rated at 20psi.

My concern is, if the springs I have are just a bad quality batch, and the new ones actually produce 20psi, is that too much boost on 93 pump? My guess is that 20psi would be anywhere between 400-440whp. Now, I’m not worrying about it mechanically not being able to take it…because it will. I’m also not worried about the tune, because that’ll be adjusted as needed. I’m just wondering about the 20psi in case the new springs actually make that. So what’s your input?

 

Since your block is most likely built, what's the compression?

above 9.0:1 - stop right now, 400 is good for pump gas
at 9.0:1 - 20PSI should be able to be done, but going higher may be a risk. I'd say 430....MAYBE 450, but why risk it on pump gas
8.5:1 pistons you can do 500, but at what PSI?

As you probably know there is no direct answer to these, and people have pushed higher. I tuned a car to 462whp on 93 pump with 8.7:1 pistons (head gasket changed)

 

Sorry, I know it probably sounds like I'm asking a newb question haha. Yes, the motor is built and the compression is 9:1. I definitely do <U>not</U> plan to go any higher than 20 on pump. The old springs were rated at 17.4psi (big yellow & small green), but then only gave me 14. Soooo I figured I'd try the big green & small green to get that extra 3psi. Oh and just for reference this is on a T3/T4 .57

 

stupid question, but why not just use an MBC to bring the boost up a few more pounds?

 

I have the Turbo XS High Pressure one but with just the small spring the boost would go to 18psi but drop to 15 by redline. I tried the Standard controller, but it did the same thing. I also tried the Dejon Tool controller, and they are just crap haha...it would go to 18 and drop to almost 7. Maybe MBC and me are not meant to have a loving relationship haha

Sooo I then tried using the big yellow & small green which put me at 14psi and it held constant till redline. So I used the boost controller again to get it up that last 4psi, but it was so touchy that I either had no change in boost or it would hit boost cut and try to spike over 20psi. I spent about 2-3 hours trying to adjust it, but it just would not work so I decided to go with just springs.

 

Brian GET THE HMBC!
For all the dumbies(Hallmans Manual Boost Controller)

 

haha yea yea yea That's the next step if this doesn't work.

 

What are you tuning with?

 

hondata....are you about to ask what the 3bar map is calibrated at? haha I thought about that too. Any info on what it "should" be calibrated at?

 

what size waastegate are running

 

Tial 38mm....I have no spiking or even creeping issues of any kind with just the two springs. It'll hold rock solid at 14.2-14.4psi with the big yellow & small green.

 

what turbo mani you using

 

LoveFab Shorty

 

I was having the same type of problem (big spring, still low boost) it ended up being the wastegate placement, i had to cut a reweld it. but it works fine now.

 

Getting 20psi on a 1 bar spring should be very easy and you shouldn't have any problems with a turbo xs mbc. Sounds like there is somthing wrong with either the wastegate or the manifold design/wg placement.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dunc &raquo;</TD></TR><TR><TD CLASS="quote">LoveFab Shorty</TD></TR></TABLE>

 

you sure you dont have a boost leak? I never heard of a bad spring...

 

Way more likely that it's a bad wastegate than a bad spring. Valve could be sticking, diaphram torn, etc...

 

But if the valve was bad or diaphram was torn on the wastegate wouldn't it cause a 7psi spring not to really hold 7psi too? Cause the 7psi spring held 6.7psi rock solid. Oh well, we'll soon see cause the new spring just came in....tuning is Friday.

I'm 100% positive I don't have a boost leak of any kind. With just the springs it spools to 14.2-14.4psi by 4500rpm and holds it till 9000. With just the small spring and MBC it would go to 18 (where I wanted it) and would fall to 15. Then with the big spring and MBC it was either stock spring pressure or would sky rocket past 20. I would start at the minimum amount on the MBC and would only turn it like 1/16th haha.

I wouldn't really consider the placement of the WG on the LoveFab Shorty bad. And the Tial 38mm was brand new and has about 1500 miles on it.

 

is the boost reference line run to the manifold or the side of the compressor

try the manifold to get a little more boost if it isn't

 

I thought that might be it because it's tapped into the compressor right now. So I T'ed it off the BOV just for testing, and the boost was still logging 14.2psi. Now that I thought was weird since shouldn't it have gone up like 2psi or so (because of the intercooler pressure drop)?

 

hmm weird i also have a lovefab shorty however i have one of the original ones not the stainless ones i think mine is mild or cast like but it is identical to yours however my wastegate elbow faces to the passenger side where as your is towards the driver side. Will i and may this be a problem for me also?

 

Actually mine is only like 2 months old...but my wastegate also faces the passenger side.