NA8 vs NB8

Engines, Transmissions & Final Drive questions and answers

Moderators: timk, Stu, zombie, Andrew, The American, Lokiel, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

NA8 vs NB8

Postby Myata » Fri Dec 30, 2011 3:35 pm

Hey all

Am going to convert my NA6 to a BP as soon as i find one available

Are there any major differnces between NA8 and NB8?

Does the NB8 need the NB gearbox etc?

Planning on turboing the BP mid next year, so is one better then the other for forced induction?

Did a bit of searching, but couldn't find an answer

Cheers, Jared
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death

project.r.racing
Speed Racer
Posts: 3722
Joined: Sun Jan 18, 2009 10:16 pm
Vehicle: Non MX-5
Location: Glasshouse Mountains, QLD

Re: NA8 vs NB8

Postby project.r.racing » Fri Dec 30, 2011 4:03 pm

massive differences. and 2 versions of the NB BP motor. google didn't turn up anything?

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: NA8 vs NB8

Postby NitroDann » Fri Dec 30, 2011 5:08 pm

If its street dríven go a 99+ motor and ms3.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: NA8 vs NB8

Postby NitroDann » Fri Dec 30, 2011 5:11 pm

Sorry I should specify, I meant a VVT motor, so 01+.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

Re: NA8 vs NB8

Postby Myata » Fri Dec 30, 2011 5:18 pm

Google didn't give me anything decent.

What's involved in a VVT conversion from NA6?

Is going to be street dríven, and then a snail put on mid next year.
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death

User avatar
geofiz
Racing Driver
Posts: 583
Joined: Fri Jun 11, 2010 1:04 am
Vehicle: NA8
Location: Perth Hills

Re: NA8 vs NB8

Postby geofiz » Fri Dec 30, 2011 5:30 pm

NitroDann wrote:Sorry I should specify, I meant a VVT motor, so 01+.

Dann


Why VVT overs VICS?


NA8 - BP4W IHI VJ35, 3.9 Torsen2, Adaptronic - SOLD
NB8A - mostly stock for now

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: NA8 vs NB8

Postby NitroDann » Fri Dec 30, 2011 5:44 pm

Spooling a turbo.

Vics helps increase port velocity at low rpm which helps a little but restricts total flow at high rpm.

VVT give much more volumetric efficiency at lower rpm, and more exhaust port timing spooling a turbo hard and fast.

Also, an NB motor has solid lifters, making cam swaps much better.

And 99+ heads flow much better than 94-97 heads.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

Re: NA8 vs NB8

Postby Myata » Fri Dec 30, 2011 6:17 pm

Ohk. So how much is involved in a VVT transplant?
cheers
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death

User avatar
bensale
Racing Driver
Posts: 1984
Joined: Tue Sep 11, 2007 7:38 pm
Vehicle: NA6
Location: Melbourne Australia
Contact:

Re: NA8 vs NB8

Postby bensale » Fri Dec 30, 2011 9:03 pm

Lightyear has just done a complete transfer of all the running gear from an nb8b (vvt 1.8) into an na6. Saw it yesterday, seemed to fit well !! I like the idea of a Frankenfive :)

Aren't the vvt engines more difficult to turbo though? I vaguely remember it being a complication for the SP's development.

NA & NB gear boxes, diffs etc are all interchangeable too.
www.othersideproductions.com
NA6-Phillip Island 1:57.7, Winton 1:42.9, Winton Short 1:12.4, Sandown 1:35.2, Wakefield 1.15.9, Nurburgring 9:17.0

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: NA8 vs NB8

Postby NitroDann » Fri Dec 30, 2011 9:25 pm

VVTs have 10:1 compression, almost high enough for an E85 turbo engine at 15psi. And they have VVT which a lot of ecu's have trouble effectively controlling.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

User avatar
bensale
Racing Driver
Posts: 1984
Joined: Tue Sep 11, 2007 7:38 pm
Vehicle: NA6
Location: Melbourne Australia
Contact:

Re: NA8 vs NB8

Postby bensale » Fri Dec 30, 2011 10:19 pm

Makes sense. Cheers for the explanation.
www.othersideproductions.com
NA6-Phillip Island 1:57.7, Winton 1:42.9, Winton Short 1:12.4, Sandown 1:35.2, Wakefield 1.15.9, Nurburgring 9:17.0

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

Re: NA8 vs NB8

Postby Myata » Mon Jan 02, 2012 11:03 pm

OK so the NB VVT motor is the way to go then. do they bolt up to the NA6 gearbox? or worth doing complete swap (gearbox diff tailshaft etc)?
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

Re: NA8 vs NB8

Postby Myata » Mon Jan 02, 2012 11:04 pm

Also, does that mean custom crossmembers etc?
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death

User avatar
NitroDann
Forum sponsor
Posts: 10280
Joined: Thu Nov 05, 2009 12:10 pm
Vehicle: NA6
Location: Newcastle NSW
Contact:

Re: NA8 vs NB8

Postby NitroDann » Mon Jan 02, 2012 11:09 pm

Straight bolt in. But the diff wont survive a week and the gearbox will make it 6 months. Do the full swap. Neither of those time frames are exaggerations.

Dann
http://www.NitroDann.com

speed wrote:If I was to do it again, I wouldn't even consider the supercharger.

Myata
Learner Driver
Posts: 18
Joined: Mon Aug 08, 2011 8:20 am
Vehicle: NA6
Location: Central coast

Re: NA8 vs NB8

Postby Myata » Mon Jan 02, 2012 11:14 pm

Sweet as

NB VVT engine, gearbox, diff and tailshaft.
Does that then require NB C.Vs and hubs, brakes etc?
FASTER, FASTER, FASTER. Until the thrill of speed overcomes the fear of death


Return to “MX5 Engines, Transmission & Final Drive”

Who is online

Users browsing this forum: No registered users and 88 guests