g2turbo

Im interested to see what boost level you guys are running in 1st and 2nd gears. This weekend in VA a few people I talked to seemed to have had problems keeping boost low in 1st gear. I saw a few cars with 48mm gates just to keep the boost controllable. I understand some of you may not want to share this information but if you dont mind please post your wastegate size/ spring rate/ and boost control method. Thanks. chris

86si

i am running a tial 44mm on my b18 with a t67 and it won't boost lower than 15lbs till bout 8k and then it creeps to 20-23 or so till 9500. i thought my boost controller was bad so i took it off and it was no diff. looks like after e-town and atco i will put another wastegate on it.

g2turbo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 86si &raquo;</TD></TR><TR><TD CLASS="quote">i am running a tial 44mm on my b18 with a t67 and it won't boost lower than 15lbs till bout 8k and then it creeps to 20-23 or so till 9500. i thought my boost controller was bad so i took it off and it was no diff. looks like after e-town and atco i will put another wastegate on it. </TD></TR></TABLE>

Art was telling me this weekend that he had problems with the 44mm gate as well, He is running the 48mm turbosmart gate now.

What boost controller are you using 86si?

Kataku2K3

Scott and I just realized towards the end of last season what most of our SFWD cars boost problems were. They all had some issue with the gate. Most of the time just being too small. We previously had always thought that it was the boost controller and tried everyone imaginable, well almost. The Blitz SBC, Innovative MSBC, XS dual stage, and back to the Blitz with the Powermeter ID on it, making it speed based. It wasn't just one car that we were changing them on, it was like 3, which got kind of old... Even the 46mm is too small in a lot of cases. What's your A/R on your hot side g2turbo? I assume yours is an .81 86si, correct? 14-20lbs seems to work well off the line, of course depending on track conditions, slick size, etc.

g2turbo

I have the gt35e/t4 with a .68 hotside.

Kataku did you guys have good results from the innovative MSBC 1? I was always under the impression that with an electronic boost controller, the top of the gate would be pressurized thus controlling boost even at lower levels??

Kataku2K3

Yea, that turbine housing is pretty small. We had a .58 on Will's T4/63 last season and it was choking everything up. Of all the boost controllers we used, I liked the Innovative the best and wish we still had them to an extent. When the surging continued up top we swapped gates (from the 46mm Tial to an Innovative ProGate), when that didn't work we ended up changing boost controllers again. Control wise, the diaphram ratio of the gate makes a huge difference. Obvioiusly when you're dealing with a larger surface area it's easier to keep shut with a smaller spring when constant pressure is applied. With the 46's we had to have ~19lbs spring combo to keep the gates shut up top (the biggest turbo was a PT67 with an .81 hot side). You really have two options that I see if that's the case, 1 - swap your turbine housing out, or 2 - run a bigger gate.


Modified by Kataku2K3 at 12:57 PM 4/27/2005

g2turbo

I think im gonna try the Turbosmart 48mm gate., hopefully that will do the trick. I have the 38mm now and can almost guarantee its not gonna do the job. Ideally i would like to have around 10-12 lbs in 1st. 15-18 in second then full boost 3 and 4.

edit: I think it would be cheaper to just purchase another 38mm gate and put it on the other side of the collector, (Lovefab Mini-me)



Modified by g2turbo at 1:58 PM 4/27/2005

SEFIxCivic

im running a 44mm wastegate with a .9 spring and at lower gears i have no problems maintaining a consistent 1 bar. im using the motec to control boost with a gm solenoid. FR top mount, GT4067

Kataku2K3

SEFIxCivic, I assume you've got the .81 turbine housing on your GT40, correct?

SEFIxCivic

haha you are so smart Ninesecteg gives me tons of advice and you know what he thinks on that subject.

Kataku2K3

Yea Nick knows his ****! The reason I ask is because Scott and I put a GT40-67 (with the .81 hot side) on Duc's car awhlie back, this was after the PT67 and it didn't do well with the Innovative ProGate at all. Took a NewGen to get it under control, and that thing is a 50mil.

SEFIxCivic

what manifold are you running? i guess on my car i can't say its exactly perfect, because i do have a .9 spring and get 1 bar consistently... but my boost doesn't creep. i do get some slight fluctaution but thats mainly because i dont have the gain and derivative perfect yet for the boost control.

Kataku2K3

That was with a Full-Race Pro Street manifold. It wasn't so much creep that we were getting (there was a little) but it was the surging that was killing us. Choking the hell out of the motor on top.

philipwight

tial 44mm wastegate and an avcr. 6psi first(needs to go up) 13psi second gear.
I have not trouble holding boost, yet.

SEFIxCivic

what does surging feel like? i wonder if i was getting that too. my top end sucked, but i mainly thought that was because my a/f was way off.

done

Im running Dual 44mm with a full race pro street manifold.. (t3/67)

It finally holds my boost right at 8psi.

Kataku2K3

It's like the motor wants to rev but it can't (in the logs we actually see the rpm fluctuate). We went though everything, reshielding the ref/sync wires on the FAST, thinking that we might have some noise inline. It also acted like the motor was misfiring, but it wasn't. We were hoping that the MSD Digi7's paired with HVC 2 coils weren't that weak. Duc's car would go ~10.7-10.8 @ 138mph (max) and would take around 6 seconds from the time you hit 4th, till the you crossed the 1320ft. mark. That's when we knew something was really wrong. I'm pretty sure I still have some of those surging logs on my USB stick, if I do, I'll post them up. It's weird ****, but in the end it was the gate...


Modified by Kataku2K3 at 4:11 PM 4/27/2005

turbo*s2k

A bit off topic, but Adam how did you like using the Blitz sbc with the power meter id??? Was it easy to setup the speed based boost?

DIRep972

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by g2turbo &raquo;</TD></TR><TR><TD CLASS="quote">

Art was telling me this weekend that he had problems with the 44mm gate as well, He is running the 48mm turbosmart gate now.

What boost controller are you using 86si?</TD></TR></TABLE>

We actually skipped the 44 all together and went straight from the 40 to the 48. We do everything bigger in Texas. I coulda got the 40 to work good enough but we went for overkill w/ the 48 and it is working great. Also u can't nessecarily pick an exact match for your combination based on other peoples combinations. As you can see in this thread there are so many variables including manifold style, turbine efficiency and motor combination, it's hard to get the exact match. You can always just go big to be on the safe side though.

Kataku2K3

I agree! BIG or multiple is good. Take John Ferguson for instance, he's running a single 60mm HKS GTII. NewGens work pretty well too. Scott and I just got done putting twin 46's on a car we just finished, hopefully they work...

About the Blitz SBC/Powermeter ID. It's super easy to setup but not as precise as I would like. That is you can only set the speed map up in the incriments it allows. If I remember correctly they're somewhere along the lines of every 10-15mph. Otherwise it works like an normal SBC.

SEFIxCivic, here's one of our logs for a while back. You can see the huge fluct. in rpm and what appears to be A:F. It was strange how it was affecting the A:F output but once we changed the gate (with the same map) the A:F was stable, just like on the dyno...

P.S. - Ignore the ignition timing if it's scaring anyone. It's a little off up there...

SEFIxCivic

check out my datalog... do my rpm fluctations looks suspicious like yours?

Kataku2K3

Yup, looks as though you have that same up-down-up-down fluct. in rpm just like we did. A motor shouldn't be doing that when you're at WOT, right? What was your Lambda like there? Dancing all around too? Looks like it's out of the range.

SEFIxCivic

yea my lambda was way off, but that was because i threw in a sx fuel pump right before the race, due to my walboro not keeping up at high boost. I knew I had to retune, but couldnt make it to the other dyno in time.

lugnuts

You guys are on the right track, but are probably overthinking a little.
The RPM fluctuations on the logs are most likely tires borderline spinning, which is actually caused by the wastegate (controller) not holding consistent boost.
The RPM and MAP fluctuations can cause a spiky A/F graph, especially if the engine is tuned to different A/F ratios vs MAP.
Andy, your boost and rpm look smooth, I bet if Kataku2K3 had a wheel speed graph it would look like the RPM

Kataku2K3

Yea, I know a lot of our A:F fluctuations are caused by spinning but in that log the car was hooked up there (at least at the very top of the gear). Here's the real short low res vid of the car... From the track to the dyno nothing was changed.

lugnuts, do you really think Andy's rpm looks smooth up there? When our cars are running correctly we don't have dips, at least with the FAST.

Just stream, there's no reason to save it and it's only 5.3mb.
SurgeSurge.wmv


Modified by Kataku2K3 at 5:34 PM 4/27/2005