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'on-boost' target RPM

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Old 16 September 2004, 10:38 AM
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markwild
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Question 'on-boost' target RPM

When AndyF mapped my car, he was concerned regarding the late 'come-on' of boost -

At the time, we noted the extremely high underbonnet temps - I've now added a cold air intake scoop to the o/s side (mini scoop) and lagged the I/C pipework under the bonnet.

I've not done the engine breather mods (vta) or built a cold-air box around the induction kit yet, but I'm reaching 1bar at the following:

2nd - 4000 rpm

3rd - 3700

4th - 3100

5th - 3000

These are obviously much higher than the TD04, but are they higher than you would expect given my car's current spec ? (does anyone have any suggested 'targets'?)

I've re-fitted the OEM D/V, as it seems to be doing a better job than the forge I fitted (particularly in partial throttle lift off)

If these figures are still too high, I'll try and track down the problem (any suggestions ?) -

Thanks,

Mark

Engine Spec:

98UK Turbo

57i, with mini scoop

TD05FE

'Hybrid' FMIC

Power FC ECU (Andy F Remap) and AVC-R, with Apexi soleniod control (Peak at 1.4 bar)

550 injectors

255 Walbro Pump / FSE fuel regulator

7B plugs

wrapped TSL up-pipe

wrapped TSL 'A' De-cat Down-pipe

TSL de-cat Centre and Grp 'N' backbox

Old 16 September 2004, 12:03 PM
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john banks
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Sounds not too bad, some have had them spooling up 100-200 RPM earlier, but tachos are not always accurate.

If concerned I would think about a careful check of the headers and uppipe for leaks, also consider a boost gauge T-d off the compressor outlet to see if there are any leaks between turbo and manifold - you'd expect it to be up to say 1 or 2 PSI higher because of the intercooler, pipework and throttle. Check the throttle is fully opening. Thereafter if still worried perhaps check the compression.
Old 16 September 2004, 01:03 PM
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Thanks John - I'm fairly sure they were a bit higher than this, when I was with Andy, due to the 'hot-air' issue, but the scoop has improved that.

I must admit, I made a mental note to check the throttle this morning, so will do that. Where does the AVC-R get its reading from ? The boost reading here and at the inlet (via the current boost gauge) are the same.

I changed the up-pipe around 6 months ago, because it had rusted through - I noticed that the headers were quite bad then, so maybe they're a bit 'leaky' (!). Some time soon'ish, I'll look to replace them with either a ported set, or a new set of unequal length ones, together with a decent inlet air pipe + another map....

Cheers,

Mark
Old 16 September 2004, 02:03 PM
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john banks
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AVC-R boost reading is from the manifold to show full vacuum which only significantly occurs between the throttle and cylinders, not between the turbo and throttle (vac is present because of suction against a closed or partly closed throttle).

AVC-R's throttle reading maxxes out well before the throttle is fully open. Worth taking an intercooler hose off and looking at the throttle plate to ensure it smoothly moves all the way when the pedal is pressed. If no helper available then you could move it at the throttle body.

3000 RPM doesn't sound catastrophically bad though.
Old 16 September 2004, 02:36 PM
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markwild
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Cheers John - the 3000 rpm in 5th is OK - Andy's main concern was the lower gears -

I notice that it pulls very well in 4th and 5th, but 4K (i.e. 2nd) seems quite high, (when I'm used to the TD04 ...) Its better now the cold air is being supplied (was more like 4.5k before), but I was unsure whether this was now a more acceptable (i.e. usual) level.

Cheers,

Mark
Old 16 September 2004, 02:46 PM
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john banks
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TD05 on a MY00 UK with FMIC and headers usually gives a fairly insistent push in the back in 2nd gear at about 3800-4000 RPM. Where exactly it reaches 1 bar I haven't datalogged.
Old 16 September 2004, 04:07 PM
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OK _ Thanks John - I suspect that it'd be a bit lower on mine if I had the headers sorted too - Something to look forward to then, eh ?

Mark
Old 16 September 2004, 05:55 PM
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What does the 'sol' reading show (avc-r) ? (solenoid ? - if so, what about it ?)

Ta,

Mark
Old 16 September 2004, 06:59 PM
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john banks
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Usually spools later with aftermarket headers.

Solenoid duty cycle. Read the AVC-R manual. Search google on duty cycle. Think of it like a dimmer switch.
Old 16 September 2004, 08:40 PM
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wrt headers - is that due to the better gas flow, so slower gas speeds ?

Solenoid question was a bit lazy - sorry - haven't used the display at all, other than for revs/boost, (its all hidden in the cubby box on the dash, under the lid) - and was 'experimenting' tonight in the traffic ... I'll read up - as I'd like to know more anyhow (I won't be altering the settings !!)

I'm hoping to improve the car 'in details', because I'm aware that I've just done a 'phase 2' upgrade and its a bit ragged around the edges, due to my concentration on the bulk, rather than minor items - e.g. no cold air box, .

Thanks for your help,

Mark
Old 16 September 2004, 09:57 PM
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john banks
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Slower gas speed during spool up, less retained heat perhaps.
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