What rpm is full boost?

Riceball777 · 09-03-2015, 09:16 PM

I have a e90 with fbo running 91 octane on map 5. My car hit full boost about 14psi at 4,000rpm. It seem kind of late and laggy to me. What rpm are you supose to hit full boost in these cars on say 3rd or 4th gear?

spxxx · 09-03-2015, 09:55 PM

Depends on boost target, age of turbos, boost leaks but full spool is generally around 3k RPM for an aggressively tuned car from what I've seen

ATTN · 09-03-2015, 11:32 PM

what he said above best to check your logs and you'll know exactly

mojobmw_e90 · 09-03-2015, 11:34 PM

I'm hitting full boost at 3k 16.8psi on map 2 with jb4 and hexon turbos that have 2k on them.

JasW · 09-04-2015, 07:06 AM

If by full boost you mean the end of the steep ramp up from 2500 RPM on a pull, I hit that at about 3100 RPM. That's 17 psi, but I hit peak boost (18.8 psi) at 4100 RPM.

mike@x-ph.com · 09-04-2015, 04:24 PM

Quote:

Originally Posted by spxxx

Depends on boost target, age of turbos, boost leaks but full spool is generally around 3k RPM for an aggressively tuned car from what I've seen

+1
Post logs

Riceball777 · 09-04-2015, 05:04 PM

Just by the jb4 fuel gauge hijack for a boost gauge it shows me hiting 12-14psi somewhere between 3,500-4,000 rpm in 3rd or 4th gear. Seam to spool slow. I will log will mbd later today and post it up. Thanks.

matthewo · 09-04-2015, 05:46 PM

15lbs at 2700rpms and 20lbs at 3700rpms

20lbs to 5200 rpms drops to 15 at redline

Stock turbos, e85 and stock inlets, 100k mile stock turbos

I'm quite surprised by them

Jeff@TopGearSolutions · 09-04-2015, 06:31 PM

Is the question when do the turbo's spool up or when do you hit peak boost? Would depend on tuning and other things but peak boost is usually right before 4000PRM.

jwebb335xi · 09-04-2015, 08:28 PM

Check logs; compare request to actual. When I was looking at a boost issue a while back, I looked at requested boost to actual boost and noticed it took almost 2 seconds at WOT to hit very near requested and stay there. Once I resolved my issue with diverter valves and logged again, I'd hit near request in well under one second..

Evil///M · 09-05-2015, 02:37 AM

21psi at roughly 4k

Odan.be · 09-05-2015, 06:20 AM

Depends,

This is what my boost curve looks like till 18.2 psi target.

http://datazap.me/u/odanbe/mhd-stage...=0&data=4-6-22

09-03-2015, 09:16 PM	#1
Riceball777 Lieutenant 163 Rep 466 Posts Drives: S2000 618whp/ e90 335i Join Date: Jul 2012 Location: Los Angeles iTrader: (0)	What rpm is full boost? I have a e90 with fbo running 91 octane on map 5. My car hit full boost about 14psi at 4,000rpm. It seem kind of late and laggy to me. What rpm are you supose to hit full boost in these cars on say 3rd or 4th gear? __________________ 2007 e90 335i pure stage 2 DD turbos, rb inlets
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09-03-2015, 09:55 PM	#2
spxxx Boost 1355 Rep 3,697 Posts Drives: 135i M-Sport Join Date: Feb 2014 Location: Valley of Silicon, CA - United States iTrader: (9)	Depends on boost target, age of turbos, boost leaks but full spool is generally around 3k RPM for an aggressively tuned car from what I've seen
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09-03-2015, 11:32 PM	#3
ATTN Major 96 Rep 1,031 Posts Drives: 335 E92 DCT Join Date: Jun 2013 Location: Sydney, Australia iTrader: (3) Garage List 2009 BMW 335i [10.00]	what he said above best to check your logs and you'll know exactly __________________ Certified Australian
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09-03-2015, 11:34 PM	#4
mojobmw_e90 Major 380 Rep 1,497 Posts Drives: 2014 E63S Join Date: Oct 2014 Location: Chicago IL iTrader: (3)	I'm hitting full boost at 3k 16.8psi on map 2 with jb4 and hexon turbos that have 2k on them.
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09-04-2015, 07:06 AM	#5
JasW Captain 255 Rep 554 Posts Drives: 2013 335is E93 6MT Join Date: Jul 2015 Location: South Florida iTrader: (0) Garage List 2013 BMW 335is E93 [8.00]	If by full boost you mean the end of the steep ramp up from 2500 RPM on a pull, I hit that at about 3100 RPM. That's 17 psi, but I hit peak boost (18.8 psi) at 4100 RPM. __________________ 2013 335is E93 6MT \| LeMans Blue/Saddle Brown BQ Tuning MHD E60 flash \| Cobb catted DPs \| ETS 5" FMIC \| BMS DCI \| Fuel-It Stage 2 LPFP \| MMP inlets/outlets \| Forge DVs \| N20 TMAP sensor Vibrant 1790 resonators/mid-cat delete \| MPI CP \| Spec Stage 3+ clutch and steel SMFW \| Wavetrac LSD \| M3 rear subframe and diff bushings
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09-04-2015, 05:04 PM	#7
Riceball777 Lieutenant 163 Rep 466 Posts Drives: S2000 618whp/ e90 335i Join Date: Jul 2012 Location: Los Angeles iTrader: (0)	Just by the jb4 fuel gauge hijack for a boost gauge it shows me hiting 12-14psi somewhere between 3,500-4,000 rpm in 3rd or 4th gear. Seam to spool slow. I will log will mbd later today and post it up. Thanks. __________________ 2007 e90 335i pure stage 2 DD turbos, rb inlets
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09-04-2015, 05:46 PM	#8
matthewo First Lieutenant 58 Rep 319 Posts Drives: 335i Join Date: Mar 2015 Location: SC iTrader: (2)	15lbs at 2700rpms and 20lbs at 3700rpms 20lbs to 5200 rpms drops to 15 at redline Stock turbos, e85 and stock inlets, 100k mile stock turbos I'm quite surprised by them
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09-04-2015, 06:31 PM	#9
Jeff@TopGearSolutions 3442 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Is the question when do the turbo's spool up or when do you hit peak boost? Would depend on tuning and other things but peak boost is usually right before 4000PRM.
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09-04-2015, 08:28 PM	#10
jwebb335xi Major 199 Rep 1,070 Posts Drives: 2008 335 XI Join Date: Jun 2014 Location: Chicago Burbs iTrader: (0)	Check logs; compare request to actual. When I was looking at a boost issue a while back, I looked at requested boost to actual boost and noticed it took almost 2 seconds at WOT to hit very near requested and stay there. Once I resolved my issue with diverter valves and logged again, I'd hit near request in well under one second.. __________________ JWebb335xi MHD / Wedge / 93 Octane/ xHP / FMIC / Inlets / Catted DPs / CP / DVs
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09-05-2015, 02:37 AM	#11
Evil///M Professional Hitman 162 Rep 998 Posts Drives: R8 V10+ \| Colorado Z71 Join Date: Feb 2011 Location: 602 iTrader: (12) Garage List 2014 Audi R8 v10+ [10.00] 2021 Ford Ranger Tr ... [0.00] 2019 BMW M2 Competi ... [9.50]	21psi at roughly 4k __________________
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09-05-2015, 06:20 AM	#12
Odan.be Private First Class 26 Rep 84 Posts Drives: Bmw E91 3351 Join Date: Mar 2014 Location: Belgium iTrader: (0)	Depends, This is what my boost curve looks like till 18.2 psi target. http://datazap.me/u/odanbe/mhd-stage...=0&data=4-6-22
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