Old school hottie build or forced induction?

[StanTheMan]

I have to say though....ITB's are scary. or I should say I find them scary. i haven't dared entertain the thought.
your Astina sounds great from inside the cabin. are you running them with filters on them?
i guess because they are right in front of the firewall the poetry & Opera are probably just a little better?

[3gress]

Yep i was running 40mm trumpets and the jenvey sausage filter. The gopro was mounted on the interior b pillar and the sound is intensified as it was reverberating off the side of the mountain. I removed the firewall insulation and the intake is aimed right at you in an astina I4 so no need for a stereo thats for sure!
In sedate driving they are not overly noisy unless you step on the (very) loud pedal.
I was never pulled over though i was parked in grafton maccas once with the bonnet open just checking things over ( showing off to the bro's...jokes ) and a paddy wagon in drive through helped push a broken down car into the carpark. They came over for a look and lavished compliments on me about 'doing it properly' and not attracting attention by leaving exterior standard looking. They did suggest enclosing the "pod filter" though in case the police pull me over!

A shot of the engine in east/west orientation.


Here is a shot from the dorrigo run just before the gopro video started.


Oh and patchy sounds bloody awesome climbing up the revs for sure!

[rascal]

I have to say though....ITB's are scary. or I should say I find them scary. i haven't dared entertain the thought.

I think ITBs get an undeserved bad rep, mostly due to lack of tuning making them run poorly.
I fitted ITBs to my NB8A a few years ago now and it was a very painless process. In fact, removing the factory inlet manifold was the hardest part of the whole install.

My tuner wasn't available at the time, so I had to tune it myself (moving from a MAP tune to a MAPxTPS tune in the process and then road tuning), and it was quite easy to get it 90% of the way there. Especially given I had almost zero tuning experience prior. I've since taken it to my tuner to sort it properly, and it runs exactly as I would like it to.

As a side benefit, it now starts way easier than it ever has, and idles better too.
Add in the protection against broken throttle shaft issues you can get with the std TB, and the sound(omg) and I'm a big fan of ITBs.

I'd recommend them for anyone that was thinking of going that way.

[Magpie]

The biggest issues for ITB's in the MX5 is getting the correct/optimum runner length in the space available. The brake booster restricts the space available.

[lucmor444]

The biggest issues for ITB's in the MX5 is getting the correct/optimum runner length in the space available. The brake booster restricts the space available.

Too right - pity we don't have the booster on the other side like in the LHD model.

[NitroDann]

You just add the length using a mandrel bend and aiming the throttle wherever they need to go to fit.

Its been done to death but you dont get internet points and mad hardparking cred without those short shiny CNC trumpets.

[3gress]

The option of removing the booster, altering brake pedal leverage point and installing an appropriately sized brake master cylinder still deprives me of sleep. The main consideration being liability issues on a street dríven car in the event of an accident whether at fault or not. Optional extra Insurance policy complications don't factor in, apart from CTP I'd prefer to stash a' just in case fund' rather than rely on a promise that will be aggressively avoided by teams of well trained, bonus seeking, morally deficient minions. Not strictly truth, the quip about preffering to stash cash, more a rant aimed at those companies that wiggle out of their obligations with little regard to the suffering of their policy holders.

[speed]

You just add the length using a mandrel bend and aiming the throttle wherever they need to go to fit.

Its been done to death but you dont get internet points and mad hardparking cred without those short shiny CNC trumpets.

I've always thought this but have never seen it done on a mx5, even when I had a quick search moments ago.

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[NitroDann]

Tonnes of factory cars have bent ones.

heres a good pic.

[speed]

I did come across that pic and also some bent trumpets on a mr2.

I like the concept of itb's and even twin TB's as we used to do in the 90's.

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[lucmor444]

Wow - that is an interesting option, how is the best way to have this done locally (ie work out best runner length etc)?

[hks_kansei]

I'm with Dann, no idea why people don't do it.

Hell, even the factory Toyota trumpets on the 4ag are curved.

[StanTheMan]

I'm with Dann, no idea why people don't do it.

Hell, even the factory Toyota trumpets on the 4ag are curved.

cause.....I'm scared

* Pussy

[Magpie]

Mine are curved and 111mm trumpets and will work with OEM booster.

[93_Clubman]

Wow - that is an interesting option, how is the best way to have this done locally (ie work out best runner length etc)?

Sam Q of SQ Engineering @ Endeavour Hills might be able to assist & there's some info on his website:
http://www.sq-engineering.com/index.php ... -throttles
http://www.my-acoustic.com/Car/intake_e ... intake.htm
http://www.my-acoustic.com/Car/intake_e ... ntake2.htm
Recall when he was developing trumpets that he posted about the development - think it was on ozclubbies:
http://www.ozclubbies.com.au/topic/3070 ... 0v-engine/
http://www.ozclubbies.com.au/topic/2986-4age-trumpets/