OUR CARS The To­tal MX-5 fleet

We’re as pas­sion­ate about MX-5S as you are be­cause, as you can read on the fol­low­ing pages, we’re own­ers, too. Each is­sue To­tal MX-5 brings you the highs and oc­ca­sional lows of our var­i­ous own­er­ship ex­pe­ri­ences

Total MX-5 - - CONTENTS -

Edi­tor Fraser tests new Dave­fab in­duc­tion kit on the rollers. Ben­nett tarts up his new mk2 and Si­mon Fox fits an ECU

AT BLOOMIN’ LAST

Af­ter many months – maybe close to a year – I’ve fi­nally got­ten around to fit­ting the Dave­fab cold air in­duc­tion kit. When I say ‘I have’, of course what I re­ally mean is that Michael Clev­er­ley has. He as­sures me that I could prob­a­bly have done the work my­self, de­spite my me­chan­i­cal in­ep­ti­tude, but the prospect of cut­ting a hole through the bulk­head, which the kit re­quires, sim­ply con­firmed to me that this was a job best left to the pro­fes­sion­als.

Just to re­cap the point of a cold air in­duc­tion kit of this na­ture: it pulls cold air from the wind­screen side of the bulk­head, which is com­pletely sep­a­rated from the heat of the en­gine bay. The cooler your in­take air, the greater its den­sity, so there’s more oxy­gen go­ing into the com­bus­tion cham­bers, help­ing cre­ate ex­tra power. Hope­fully.

Dave­fab sup­plies its cold air in­duc­tion kit not only with com­pre­hen­sive in­struc­tions, but also a printed pa­per tem­plate for cut­ting the afore­men­tioned breach in the bulk­head, com­plete with po­si­tion­ing holes, through which you in­sert the washer bot­tle’s two fix­ing bolts on the bulk­head to en­sure it’s in pre­cisely the cor­rect po­si­tion.

Be­fore any of that could hap­pen, though, there was the ex­ist­ing air­box and its as­so­ci­ated plas­tic pipework to re­move, as well as the washer bot­tle, which was sit­ting right where the hole needed to be. My ear­lier ob­ser­va­tion that some things are best left to the pros was borne out by the speed at which Michael dived in, un­did bolts and clips, pulled out pip­ing, and left ex­posed a con­sid­er­able chunk of en­gine bay. Left to my own de­vices I would still be fid­dling around in the dark, try­ing to dis­cover what it was doggedly hold­ing a big bit of plas­tic in place.

With the as­sis­tance of the pa­per tem­plate Michael scribed the ap­pro­pri­ate di­am­e­ter cir­cle into the metal of the bulk­head, at which point he re­alised that he didn’t have a 64mm di­am­e­ter hole saw on the premises. Ever one to rise to a chal­lenge, he set about cut­ting the hole ‘the old fash­ioned way’. That is, by us­ing a reg­u­lar metal drill bit to cut closely spaced holes all the way around the di­am­e­ter of the scribed cir­cle, then us­ing a punch to chisel through the

re­main­ing metal be­tween the holes, then fi­nally per­fect­ing the cir­cle and smooth­ing away rough edges with a small abra­sive disc. It might have taken longer than do­ing it with a hole saw, but I get the feel­ing that Michael en­joys the more hands-on, man­ual ap­proach.

The Dave­fab air­box is a cu­ri­ous-look­ing thing, but beau­ti­fully welded and fin­ished, and crowned by a badge that’s etched onto a lit­tle metal plate that’s cop­per pop-riv­eted to the top of the de­vice. Get­ting its cylin­dri­cal in­let pipe to poke far enough through the bulk­head

(in the di­rec­tion of the base of the wind­screen) so that Michael could af­fix its al­loy bell­mouth col­lar on the other side of the bulk­head was trick­ier than we thought it would be.

En­larg­ing the main hole slightly gave us a lit­tle more wig­gle room, but still an in­suf­fi­cient length of pro­trud­ing pipe to at­tach the bell­mouth to. Even­tu­ally Michael had the brain­wave of elon­gat­ing one of the bolt holes on the box’s fix­ing plate, al­low­ing the whole thing to shuf­fle back­wards a cou­ple of mil­lime­tres, which did the trick. What you must re­mem­ber to do, though, be­fore bolt­ing every­thing firmly in place, is pull the air­box back out slightly so that you can open it and in­sert the air fil­ter.

With every­thing in place, at­tached, and bolted se­curely, Michael turned his at­ten­tion to the Dave­fab scut­tle-mounted re­place­ment washer bot­tle. It’s an­other neat piece of steel fab­ri­ca­tion and is sup­plied with every­thing re­quired to get wa­ter to and from it, plus the rel­e­vant elec­tri­cal con­nec­tions. Even Michael was im­pressed, es­pe­cially with the heat-shrink plas­tic sleeves for pro­tect­ing the elec­tri­cal con­nec­tors. He did point out, though, that for all the bot­tle’s stylish looks, it doesn’t ac­tu­ally hold much washer fluid, but then I don’t ever use much washer fluid.

Prior to get­ting the Dave­fab gear fit­ted, I’d been back to see Sam and Matt at nearby Hy­brid Tune to get ‘be­fore’ power and torque read­ings. In fact, I’d first

gone there last Au­gust, on a day that was gen­uinely hot, but Sam in­sisted that what I re­ally must have was win­ter tem­per­a­ture ‘be­fore’ read­ings. And back on a nippy day in Fe­bru­ary my MX-5 achieved a max­i­mum power fig­ure of 121.8bhp with the bon­net down, and 123.4bhp with it up for greater cool­ing. The torque fig­ures were 111.9lb ft and 114lb ft re­spec­tively, both at just over 5000rpm.

An­noy­ingly there was quite a gap be­tween Michael fit­ting the Dave­fab kit and me be­ing able to get back to Hy­brid Tune: I re­ally wanted to know those ‘af­ter’ fig­ures. Par­tic­u­larly as my MX-5 now sounds awe­some, all deep-throated and old school twin-cammy. Rorty you’d have called it back in the day. You don’t get the full audio the­atrics un­til the tacho nee­dle passes 3000rpm, but then it builds steadily in vol­ume and ag­gres­sive­ness, turn­ing al­most to a shriek as you reach 7000rpm and need an­other gear. Even if there were no power in­crease from the kit, this evoca­tive sound­track should en­sure you’ve no re­grets about splash­ing out on it. And this is in con­junc­tion with just a stan­dard mk1 ex­haust.

It’s all very much sub­jec­tive, I know, but a good in­duc­tion sound can trans­form what you feel about your car and af­fects the way you drive it. I’m now much more in­clined to rev mine out to near the lim­iter in ev­ery gear, and I’m driv­ing it quicker point-to-point, too, a fact I know not from keep­ing an ea­gle eye on the speedo, but be­cause I’m hav­ing to brake far harder on the ap­proach to fa­mil­iar cor­ners. The MX-5 is more sat­is­fy­ing to drive, sportier.

As a con­se­quence of the dis­rup­tion caused by the Beast from the East, Hy­brid had a spare slot to put the MX-5 back on the rollers once the snow had cleared. And the re­sults were in­ter­est­ing. The Dave­fab kit pro­duced 126.7bhp at 6500rpm re­gard­less of whether the bon­net was open or closed, prov­ing the value of sourc­ing your in­take air from out­side the en­gine bay. Com­pare that with the 121.8bhp achieved bon­net down with the stan­dard in­duc­tion setup: Sam, how­ever, reck­ons the com­par­i­son should be against the bon­net up fig­ure of 125.8bhp from the fac­to­ryspec in­duc­tion sys­tem, rea­son­ing that an en­gine gen­er­ates more heat on a rolling road than it would on the open road, and there­fore is ‘owed’ as much ex­tra cool­ing as it can get.

Now I know Sam’s the ex­pert – and I’m sure many of you will share his opin­ion – but I’m stick­ing with the 4.9bhp in­crease from the bon­net down sce­nario. Makes me feel hap­pier. Frankly, though, the kit’s worth it for the noise it makes alone.

Thanks to: Sam Weller and Matt Will­goss at Hy­brid Tune (07552 238737), and Michael Clev­er­ley of Cleverely Re­paired Cars (01379 384046).

Stan­dard in­duc­tion ap­pa­ra­tus seems huge once you’ve re­moved it from the en­gine bay

Dave­fab cold air in­duc­tion kit draws cool air from the other side of the bulkead, away from the heat of the bay

Pa­per tem­plate for hole’s po­si­tion

…and get chis­elling

No hole saw? Start drilling…

Edi­tor Fraser’s mk1 gets the rolling road treat­ment cour­tesy of the lovely chaps at Hy­brid Tune: owner Sam Weller is the man be­hind the wheel

The Beast from the East couldn’t stop Fraser’s mk1 from trav­el­ling

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