Boost Fluctuations on Data Logger

[horndog]

I am getting a fluctuation of boost on my data log for wide open throttle. I have read on some forums that it is normal and you can smooth it simply by putting a restrictor on the MAP sensor for those engines that run timing referenced with boost.

I just wanted to ask if others have experienced this and is it normal or can there be an identified issue causing it?

Turbo Gurus?

Time Boost RPM
32.200 1.2 5590
32.300 2.8 6010
32.400 3.6 6085
32.500 4.3 6330
32.600 3.2 6475
32.700 3.6 6823
32.800 5.0 7133
32.900 4.1 6926
33.000 3.7 5516
33.100 4.8 3892
33.200 3.4 3502
33.300 3.6 3522
33.400 2.5 3810
33.500 1.7 4044
33.600 1.9 4292
33.700 2.8 4538
33.800 1.9 4822
33.900 1.7 5054
34.000 2.1 5331
34.100 3.7 5583
34.200 2.3 5858
34.300 2.6 6136
34.400 2.8 6427
34.500 4.3 6730
34.600 3.0 7046
34.700 3.7 7349
34.800 4.8 7693
34.900 4.5 8005
35.000 4.7 8343
35.100 4.7 8678
35.200 4.1 9000
35.300 6.1 9278
35.400 6.1 9593
35.500 5.2 9860
35.600 5.6 10127
35.700 1.7 8539
35.800 2.5 8393
35.900 3.6 7801
36.000 3.2 7972
36.100 3.6 8170
36.200 4.8 8348
36.300 3.7 8491
36.400 4.8 8656
36.500 4.3 8811
36.600 4.5 8965
36.700 4.3 9101
36.800 4.5 9278
36.900 5.2 9423
37.000 5.4 9567
37.100 5.6 9735
37.200 5.2 9881
37.300 5.8 10068
37.400 5.8 10187
37.500 6.9 10332
37.600 6.9 10489
37.700 6.3 10618
37.800 6.7 10783
37.900 6.5 10911
38.000 7.4 11050
38.100 6.3 10980
38.200 5.9 11104
38.300 2.5 8229
38.400 1.9 9462
38.500 3.7 8873
38.600 3.0 8913
38.700 3.4 8994
38.800 5.0 9089
38.900 5.4 9149
39.000 4.5 9228
39.100 4.5 9297
39.200 5.8 9372
39.300 4.7 9462
39.400 5.8 9540
39.500 5.2 9607
39.600 5.0 9681
39.700 6.9 9749
39.800 5.2 9811
39.900 5.2 9903
40.000 5.9 9981
40.100 6.5 9832
40.200 3.6 9560

[Matturbo]

Mine does that too, jumps 2 PSI in .1s usually sits around 8PSI with a 7 PSI spring. Not sure of cause.

[spamanglenn]

8psi and 149mph?? what going on there? is it decompressed or something.

[GRUNTMAX]

Not an expert on this, but maybe you need an AMS1000 boost controller from NLR USA, and LP air loading your wastegate instead of boost pressure. (a small electric air compressor that cuts in at 90psi & shuts down at 120 psi loadind a small volume tank such as the ones built into a bigccracing swingarm and loading your wastegate.) While your at it, you may as well install a watermist injection system so you can increase your boost pressure.

[horndog]

I think I may have found a contributing factor to my issue, I was getting some exhaust gas bypassing around the turbine through the wastegate port. I have fixed it up now and the turbo sounds like it is spooling better already just from free revving.

Some comments from the guys on the U.S forums suggest it should be making full boost quicker so hopefully this will help.

Next time out for some laps will tell if it has made a difference.