Tur­bocharged and Su­per­charged

Total MX-5 - - NEWS -

Amer­i­can MX-5 tun­ing spe­cial­ist, Flyin’ Miata, has been kick­ing its way into the head­lines with the an­nounce­ment of a pos­si­ble ‘twin­charger’ con­ver­sion for the 2.0-litre en­gine in the mk4. Twin­charg­ing in­volves stick­ing both a tur­bocharger and a su­per­charger un­der the same bon­net.

Those of you with long mem­o­ries may re­call that the most fa­mous ex­po­nent of this forced in­duc­tion dou­ble-act was Lan­cia, which fit­ted both sys­tems to its stun­ning 037 Group B rally car – the fact that the mid-en­gined mon­ster won the 1983 WRC man­u­fac­turer’s ti­tle for Lan­cia rather val­i­dated the po­ten­tial of the tech­nol­ogy. More re­cently, Volk­swa­gen has used twin­charg­ing on very small en­gines to pro­vide de­cent per­for­mance com­bined with good econ­omy and emis­sions.

Flyin’ Miata’s in­ten­tion for the twin­charger setup is purely per­for­mance, but there’s a way to go yet be­fore we learn pre­cisely how much power it might make. How­ever, it should be north of what the com­pany’s tur­bocharger con­ver­sion – sup­plied by Bri­tish spe­cial­ist, BBR – on its own achieves, which is in the re­gion of

250bhp. The twin stum­bling blocks to an­nounc­ing some­thing more de­fin­i­tive on the power front, ac­cord­ing to Flyin’ Miata’s Keith Tan­ner, is that the car’s ex­ist­ing fuelling ar­range­ments can’t keep pace with the hun­gry de­mands of the twin­charger sys­tem, and that the en­gine’s in­ter­nals are likely not strong enough and need more ro­bust re­place­ments.

The cre­ation of the twin­charger con­ver­sion came about by ac­ci­dent. Flyin’ Miata’s tur­bocharged RF demon­stra­tor ar­rived in the work­shop to have its turbo re­placed by an Edel­brock su­per­charger. But then some­one sug­gested leav­ing the turbo in place, just to see if in­stalling a su­per­charger as well could be done. It could.

Forced in­duc­tion du­ties are ini­tially han­dled by the tur­bocharger, which feeds air through an air-to-air in­ter­cooler; the air’s then in­tro­duced to the su­per­charger be­fore pass­ing through an airto-wa­ter in­ter­cooler and into the en­gine. Find­ing room in the nose for both in­ter­cool­ers was one of the key pack­ag­ing chal­lenges.

We look for­ward to see­ing the com­pleted ma­chine.

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