band.We would now try to match it with the Boost Graphic.
The Boost Graphicis an electronicboost pressure adjusterand mappingdevice.It hasa mastersliderto set maximumboost level whereveryou want it; 5psi, 30psi,wherever.The master slider then actslike an
e went to Middlesex Tuning's rolling road in Northolt to fit and test the Boost Graphic from
Superchips.Its nameis derivedfrom the Boost Graphic's ability to alter boostpressuresand, well... it lookslike a graphic equaliser.The red lights,sliding buttonsand plasticcasewere certainlytacky,but there'ssome cleverthoughtbehind it. For the purposeof our test,we usedthe SierraCosworthof Dave Guildford at MTC. The first dyno run showeda very standard205bhp at 6600rpm.We alsoplotted the boostcurvewhich showedlpsi at 2650rpm.Itthen roseto 6psiat 3000rpmand Tpsiat 3100rpm, whereit remaineduntil6600rprn. This curveis superblyflat and gives the Cosworthits continuouspower
adjustable boost setting. The other seven sliding controls are calibrated with engine speed. As the engine reaches the rev band indicated, you adjust the slider to give a percentage of the maximum boost selected. It's an aftermarket version of what Ford spent millions programming into the Cosworth's ECU. It's ideally suited to turbo vehicles such as the Renault 5GT, Uno and the Nissan Silvia and Cherry, all of which don't have mapped boost. Those cars tend to peak early and boost falls off rapidly,limiting top end power. We aim to fit the Boost Graphic to one of these cars, but first we wanted to prove it against the Ford system.
flow fDoes It Work? The Boost Graphic works by electrically operating an amal valve to control boost pressure,bleeding off what isn't needed. The instructions suggest it can operate the standard valve on cars fitted with such a device. However, a
It lookstacky butactually hasa lot of potential lor certainturbo'dcars special amal valve, called a boost control valve is also supplied with the fitting kit. This is for vehicles without a factory valve or electronic mapping, such as mentioned previously. Unlike the Cosworth valve, which is either open or closed, the boost control valve can be open, closed, or slightly ajar, allowing precise adjustment.
itting First connect the wires to the circuit board by disassembling the box. There are five connections which, taken in order, are aIZY feed, a tacho supply from the coil, two wires for the amal valve and an earth. The tacho wire allows the unit to calibrate its 500rpm increments from 2500rpm to 5000rpm with a jump to 6000rpm. Although there are two valve connections the second is for twin turbos only. Next step is to tell the unit how many cylinders you have, using a combination of three switches on the board. Alongside this is the trim screw to set maximum boost
on the master slider. At this point we encountered several problems which took hours to resolve. Initially, the graphic wouldn't operate the Cosworth's amal valve so, after experimentation, we fitted the boost control valve supplied. It now worked but the trim screw gave us either 5psi or 20psi and nothing in between. Consulting Superchips, we reversed the wiring on the valve and everything was fine, becoming
TheBoost Gnaphic hnings electnonic boost contnol totnefikesofRenault bGT andUno Tun[o owner$, aswediscouen inthelinst
Tpsiboostcurve. With the masterslider set at maximum (representing 10psi), we moved the seven rpm sliders to minimum and proceeded to run through each 500rpm increment on the scale.Dave held the
revs at 2500rpm,while we adjustedthe first slider until the boostgaugeread7psi. The engipewasthen held at 3000rpmand the procedure repeated.This wasdoneright up to 6000rpm and a full power run confirmed the engine was holding /psl. Again it's easy to write but not so simple in practice. The problem is turbos generate massesof heat and there's no way of removing it effectively. The more tests we carried out, the more heat we had. Over the course of three power runs we lost 3psi and 15bhp from previous settings, and severe pinking began to occur. Bear in mind, we were running low boost levels. To increase performance we might typically aim for 15psi across the board which would produce greater heat, and dangerous detonation. There are two solutions. Firstlv. allow long periods between each dyno run to cool the engine, or set the Boost Graphic on the road. This second option needs a very straight road and could be extremely dangerous while you hold precise engine speedsin fourth gear for prolonged periods.
Thisisthe valvebit, which controls how muchboost youget.lt's controlled by thesliders on theboosl graphic, don'tyou know!
fully adjustable from 5psi to 20psi
The instructions said: "Turn the trim screw fully anti-clockwise and move all the sliders to maximum." With an accurate boost gauge measuring vacuum, you adjust the trim to whatever maximum boost value is safe for the engine. We chose 10psi since we were attempting to match the original
Here's themanthatdoes, fiddling with thethingtosetit up.Hope heknows whathe'sdoing
GWHICTERMS BOOST CONTROT
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1psi.We lost out slightly in mid range but pulled out again to draw level at 6600rpm,were we recorded204bhp. After a day unravellingthe Boost Graphic we were pleasedto achieve theseresultsand are now confident we could match the Cosworthpower curve almost exactlv. given more practice. But Dave Guildford SECOND didn't feel the system VALVE FOR wasfully exploited on BI.TURBOS the Sierra;hewanted EARTH to try a Renault 5GT or LJnoTurbo to see what it could really do.
Inevitably, the driver must concentrateon revs and wouldn't be looking where he's going.
The Results Eventually we programmedthe sevenrpm slidersto Tpsibut the Cosworthwasnow shagged.A power run confirmed the Boost Graphic had programmedTpsi from 2500-6000rpm.The power curye showedmore bottom end power sincewe had Tpsiwhere the Ford programmeonly allowed z1.g t:fs l?'n 158 13a 116 9B ?g 5E 38 10
The Boost Graphic hastacky packaging but is a clever engine managementsystem with full control over boost pressuresacross the useful rev range.It could be a revelation on vehicleswithout this facility asstandard,sinceit should be possibleto overcomeinherent problems at low and high engine speeds.Essentiallywe fitted it to the wrong car, but intend to rectify that in a future issue. Dave Guildford wasvery enthusiasticabout the product. He claimed:"I've never seenanything that mapsboostlike that.It manipulatesthe turbo better than anything else.However, we need to find somethingwith horrible boost Here's the powerGurve. WiththeBoost Graphic wegot morepower lowdown,lost a bitinthe m i d dland e gained again attheend.A lairresulton lheday,the ladswillbe happy with that,Brian
curves,sincethe Cosworth systemis just too clever. Readerswill need to useimagination to seethe full potential of this box becausewe haven't appliedit properly... yet. It's very clever, though." Although we didn't fit it properly, the plasticcase must be drilled for the wires to exit. A suitablemounting positionmust then be found. The dashboardis an obvious location but, after severalhours on the dyno,I'd be annoyedto have passengerssliding the buttons and wrecking the mapped boost curve. It would, however,give the driver accessto adjustableboost, for wet or dry conditions,via the master slider. Locating under the bonnet wouldn't be clever sincethere's no water-proofing.So the ideal solution callsfor mounting within reach of the driver. awav from passengersand with therpm sliders disconnectedso that the map can't be disturbed.The driver could then control maximum boost by the
master slider. Unfortunately, this facility is not available,so beware of passengersattempting to detonateyour engine. As for cost,the Boost Graphic is f2T6tncluding VAT from Superchips'dealers,suchas Middlesex Tuning. On top of that you should allow for fitting and rolling road costs. MBP