Peak boost

[WiNgNuTz]

Ive seen a few people comment that they hit peak boost at around 2-2.5k rpm, but mine seems to build slowly and only peak just as im about to change gear at 4.5k.

Before i go any further, could it be due to the fact i'm still running the Lucas pump that came on the car? Im sure the others that ive spoken to have been Bosch'd already. Either that, or could my turbo be nearing the end of its useful life?

Any suggestions would be appreciated, it doesnt really bother me, as im still loving just having boost, but its one of those niggling little things in the back of your head, just thought id get your take on things. Cheers guys/gals!

[Tom]

Boost leak maybe?

[WiNgNuTz]

Not that ive found so far, peaks at 18-19psi, but as i say, its only as i change gear.

[Tom]

Im no expert but you should be at full boost and holding by 3K atleast... I think.. lol

[WiNgNuTz]

Thats the problem, im not an expert either....far from it!

Im learning though, albeit as i go along, but im learning!

[4WayDiablo]

I dunno why it would take so long to hit peak boost. I take it you have tinkled with the pump? It may be that your not delivering enough fuel low down.
Mine hits peak boost(28psi) around 2.6-2.9 and holds till 4.5+ but I'm changing by then anwyay

[londondan86]

Agree with 4way, it should make peak boost by 2.5-2.8k. I would be looking for a boost leak. Does it smoke at all when on blow?

[4WayDiablo]

Agree with 4way, it should make peak boost by 2.5-2.8k. I would be looking for a boost leak. Does it smoke at all when on blow?

Thing is though with a boost leak you'll still hit peak boost but it will be a lower peak. Mine still hits peak at pretty much the right time with or without a leak

There must be something up with the turbo or fuelling if its not getting boost

[Ryan@306]

mine also does this gets to around 20-21psi at around 4k but is at around 14psi at 3k but it smokes like a bitch in the lower revs i.e. 1200-2200 due to max fuelling and boost compensator (although 80% is probably boost compensator as its wound out to around 3 threads showing)

[londondan86]

Agree with 4way, it should make peak boost by 2.5-2.8k. I would be looking for a boost leak. Does it smoke at all when on blow?

Thing is though with a boost leak you'll still hit peak boost but it will be a lower peak. Mine still hits peak at pretty much the right time with or without a leak

There must be something up with the turbo or fuelling if its not getting boost

Yes but if its chuffing black smoke then surely there is fuel. You still may be right though, just need a few more details me thinks.

[4WayDiablo]

Putting out shit load of black smoke? Didn't see that bit lol but that could be some epic bogging? Not sure tbh

[WiNgNuTz]

Chuffs out black smoke like nothing ive ever seen before low down the revs, but is pretty much clean on blow. I tried adjusting the boost compensator after reading these posts, and its helped a bit, gonna tinker some moar tomorrow when ive got some light to work with. Turned the fuel down a bit earlier as well to try and reduce the epic smoking habit, but all ive done is lost boost, only peaking about 17psi now, so that'll be turned up again tomorrow.

Any more details needed, just ask, im here to learn all i can!

[WiNgNuTz]

Well, ive pretty much sorted it, may just need a little extra adjustment to get it just so. I believe the issue was due to the boost compensator (or whatever the Lucas equivalent is called) being wound too far in, thus restricting fuel at lower revs. At least, thats pretty much how i read it.

Rep has been given to both 4way, and Ryan@306 for saying the things that made the connection in my head. Cheers guys!


/thislesson

[CJ_Derv]

the boost compensator pretty much does naff all on a lucas anyway to be honest, your always going to get off boost coal on a lucas and cant realy control it much.

Best thing to do is get a Bosch and Gov mod it and then youl be able to hold boost right up to 5.5k easily and boost compensator is soo much better to adjust i have hardly and coal off boost and non on boost and running TD04L with lots of power