Problem hitting boost targets from 3k -5k

drfrink24 · 09-13-2005, 06:38 AM

I've been playing around with my WGDC low/high, with the intent of trying to hit 18 psi in the midrange, tapering to 15 psi by redline.

I've got headers/catted TBE/panel filter.

With stage2v1.04 as a base for the WGDC and boost targets, I'd rarely see over 15ish PSI as a peak (before headers too). I've never had creep in any temps with my car, and even with stage2 AP, I'd rarely see over 16psi on the gauge, even at -30F.

So, I bumped up my targets to 18.03 (from 17.5), and did some modest bumping of the WGDC by 5% in some areas from both low/high.

Initial results were better, with some peaks in the high 16s, but, still not able to hold much more than 12 PSI by redline.

So, I bumped up my low and high even more. Boost has now dropped off signifigantly. I'm seeing 81% WGDC, with 14-15PSI peaks.

Besides mechanical reasons, what could explain this?

I'm thinking of trying to copy/paste the HWG maps from cobb into my map, or, at least comparing them. The biggest concern for me so far is that I'm seeing the highest WGDC I've ever seen in the logs, with some of the lowest boost levels I've ever seen in the midrange.

STirish · 09-13-2005, 07:05 AM

*Edit*
What altitude are you at? The higher you are the higher the shaft speeds.

Are you spiking at all? If you spike too hard the WGDCs fall fast and then rapidly clime again, but it's too late.

Can you post your boost target and WGDC low maps? It seems the VF39 is poorly quality controlled meaning that some are more efficient than others. There are guys at sea level that can't make over 12psi at read line. I make 12.5psi at read line here in Denver.

drfrink24 · 09-13-2005, 07:13 AM

Let me do this. I'll review my changes, compared to cobbs HWG (if possible), then I'll do some 3rd gear logging, and post everything up.

Come to think of it though, I have seen the boost gauge spiking (not all the time), but, no apparent spiking in the logs.

***EDIT***

Apparently, Cobb doesn't provide a HWG ST map... Or, I haven't been able to find it...

drfrink24 · 09-13-2005, 06:11 PM

I verified the correct map, resaved it even, reset the ECU, loaded the realtime map, and went of fer sum loggin'

As with my high EGT problems, the boost problems went away with an ECU reset. I don't know what the deal is with these magical resets..

Anyway.. for those curious, here is what I've got, peak numbers are good now, just not holding much. It also does look like it might be too much initial WGD?

3rd gear pull, eased into the throttle, first data is at 100% throttle.

Code:

RPM	Boost	WGD
3101	9.86	70.98
3227	12.76	75.29
3501	17.69	75.29
3669	18.42	74.9
3946	18.42	73.73
4117	18.13	74.12
4289	17.55	75.69
4550	17.4	77.65
4726	17.11	78.82
4881	16.97	79.22
5109	16.24	80
5282	15.95	80.39
5392	15.52	80.78
5660	14.65	81.18
5776	14.36	81.18
5990	13.92	81.18
6052	13.63	81.18
6165	13.63	81.18
6379	13.05	81.18
6456	12.91	81.18
6554	13.05	81.18
6801	13.05	81.18

jays05 · 09-13-2005, 06:31 PM

I would bump up the WGDC by a couple points at 4800+ on the low map and 5600+ on the high map and try again.

You could try pulling a point or two at 3600 but it doesn't look like it is overshooting target boost too much since it only reduces the WGDC by one point. I don't think that is the problem, I'd fine tune that later or just enjoy the boost spike

Adding a helper spring to the wastegate is a cheap mod that has helped me and a few others hold more boost to redline. I run a 9lb helper spring and also the perrin EBCS (which helped a lot) and I can hold 15.5psi at redline with the WGDC at 61% in my logs. Before those mods, I was running 85%+ in my logs pretty much across the board and had 14-14.5psi at redline.

WolfPlayer · 09-13-2005, 06:57 PM

My high map is very similar to yours. You might want to try setting your 6400rpm point to 95% (high) and 85% (low). Reset the ECU and go for a roll. That netted me 1/2lb+ in the upper RPMs. If you aren't happy with that then go with the Perrin Solenoid (or GM solenoid). If you still aren't happy then add the wastegate spring. I am at the Perrin Solenoid step now. Sitting on the table calling my name to install it. I also have the helper springs too ... but am waiting to install one until after the Perrin is in and tuned.

t

09-13-2005, 06:38 AM	#1
drfrink24 Junior STI Driver Car: JBP 04 WRX STi Posts: 197 Join Date: May 2004 Trader Rating: (0)	Problem hitting boost targets from 3k -5k I've been playing around with my WGDC low/high, with the intent of trying to hit 18 psi in the midrange, tapering to 15 psi by redline. I've got headers/catted TBE/panel filter. With stage2v1.04 as a base for the WGDC and boost targets, I'd rarely see over 15ish PSI as a peak (before headers too). I've never had creep in any temps with my car, and even with stage2 AP, I'd rarely see over 16psi on the gauge, even at -30F. So, I bumped up my targets to 18.03 (from 17.5), and did some modest bumping of the WGDC by 5% in some areas from both low/high. Initial results were better, with some peaks in the high 16s, but, still not able to hold much more than 12 PSI by redline. So, I bumped up my low and high even more. Boost has now dropped off signifigantly. I'm seeing 81% WGDC, with 14-15PSI peaks. Besides mechanical reasons, what could explain this? I'm thinking of trying to copy/paste the HWG maps from cobb into my map, or, at least comparing them. The biggest concern for me so far is that I'm seeing the highest WGDC I've ever seen in the logs, with some of the lowest boost levels I've ever seen in the midrange. This ad is not endorsed by this member. Please register or login to hide this ad.

09-13-2005, 07:05 AM	#2
STirish Spec C Club Car: '99 M3/'03 WRX Avant Fav Mod: Modification is wrong! Location: SLC, UT Posts: 1,026 Join Date: Sep 2004 Trader Rating: (6)	Edit What altitude are you at? The higher you are the higher the shaft speeds. Are you spiking at all? If you spike too hard the WGDCs fall fast and then rapidly clime again, but it's too late. Can you post your boost target and WGDC low maps? It seems the VF39 is poorly quality controlled meaning that some are more efficient than others. There are guys at sea level that can't make over 12psi at read line. I make 12.5psi at read line here in Denver. Last edited by STirish : 09-13-2005 at 07:44 AM.

09-13-2005, 07:13 AM	#3
drfrink24 Junior STI Driver Car: JBP 04 WRX STi Posts: 197 Join Date: May 2004 Trader Rating: (0)	Let me do this. I'll review my changes, compared to cobbs HWG (if possible), then I'll do some 3rd gear logging, and post everything up. Come to think of it though, I have seen the boost gauge spiking (not all the time), but, no apparent spiking in the logs. *EDIT* Apparently, Cobb doesn't provide a HWG ST map... Or, I haven't been able to find it... Last edited by drfrink24 : 09-13-2005 at 07:23 AM.

09-13-2005, 06:11 PM	#4
drfrink24 Junior STI Driver Car: JBP 04 WRX STi Posts: 197 Join Date: May 2004 Trader Rating: (0)	I verified the correct map, resaved it even, reset the ECU, loaded the realtime map, and went of fer sum loggin' As with my high EGT problems, the boost problems went away with an ECU reset. I don't know what the deal is with these magical resets.. Anyway.. for those curious, here is what I've got, peak numbers are good now, just not holding much. It also does look like it might be too much initial WGD? 3rd gear pull, eased into the throttle, first data is at 100% throttle. Code: RPM Boost WGD 3101 9.86 70.98 3227 12.76 75.29 3501 17.69 75.29 3669 18.42 74.9 3946 18.42 73.73 4117 18.13 74.12 4289 17.55 75.69 4550 17.4 77.65 4726 17.11 78.82 4881 16.97 79.22 5109 16.24 80 5282 15.95 80.39 5392 15.52 80.78 5660 14.65 81.18 5776 14.36 81.18 5990 13.92 81.18 6052 13.63 81.18 6165 13.63 81.18 6379 13.05 81.18 6456 12.91 81.18 6554 13.05 81.18 6801 13.05 81.18

09-13-2005, 06:57 PM	#6
WolfPlayer Moderator & ECU Tech Car: 05 CGM STI Fav Mod: mo boostaz Location: Fredneck, MD Posts: 3,702 Join Date: Jun 2004 Trader Rating: (6)	My high map is very similar to yours. You might want to try setting your 6400rpm point to 95% (high) and 85% (low). Reset the ECU and go for a roll. That netted me 1/2lb+ in the upper RPMs. If you aren't happy with that then go with the Perrin Solenoid (or GM solenoid). If you still aren't happy then add the wastegate spring. I am at the Perrin Solenoid step now. Sitting on the table calling my name to install it. I also have the helper springs too ... but am waiting to install one until after the Perrin is in and tuned. t This ad is not endorsed by this member. Please register or login to hide this ad.

09-13-2005, 06:31 PM	#5
jays05 Spec C Club Car: Blue 05 STI Fav Mod: Synapse FMIC Location: Upstate NY Posts: 1,700 Join Date: Nov 2004 Trader Rating: (0)	I would bump up the WGDC by a couple points at 4800+ on the low map and 5600+ on the high map and try again. You could try pulling a point or two at 3600 but it doesn't look like it is overshooting target boost too much since it only reduces the WGDC by one point. I don't think that is the problem, I'd fine tune that later or just enjoy the boost spike Adding a helper spring to the wastegate is a cheap mod that has helped me and a few others hold more boost to redline. I run a 9lb helper spring and also the perrin EBCS (which helped a lot) and I can hold 15.5psi at redline with the WGDC at 61% in my logs. Before those mods, I was running 85%+ in my logs pretty much across the board and had 14-14.5psi at redline.