I fancy ITBs on my '99 1.8 Mk2 Sport.... What are the advantages/disadvantages?

Am I wasting my money putting ITB’s on my Mk2?  I fancy doing it, but know nothing about it Undecided… Can anyone enlighten me please?



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I don’t know anything about it but it’ll look bloody good under the lid :slight_smile: & it would sound FAB.
will the cost be justified by enough extra power though?

Hi Tony,
Funnily enough I’m dabbling with the same idea.
Regarding the waste of money, it might depend on what your end goal is.
If you are looking for ultimate power then a turbo would give you more bang for your buck.
If it’s aesthetics, sound and character then ITBs are hard to beat IMHO.
Apparently BBR are developing an NB ITB set up that was showcased at last year’s national rally. I couldn’t find anything on their website but did spot an article in one of the mags.


Oops! Just seen when this was first posted. Sigh sorry folks.
Admin, please feel free to delete this.

Lots on YouTube regarding this.
Decent power hikes ( apparently) at hand in conjunction with remaps etc.
Darned if I can recall just now but saw a professional tune shop job ITB Mk3.5 churning out well over 200bhp sans forced induction. It may also have had modded lifters etc though.
I do know of an 1840cc Mk1 around 30 miles from me with ITBs, and it goes like the proverbial S off a S…with cracker jack sound tracks…but no idea what else was added.
Sounds like a well tuned Sunbeam Lotus on a track day.
It left me red lining the wife’s Sport totally dead. Little booger. Hissed me off good 'n propah.

I have an 1800 Eunos with 169 BHP on throttle bodies. It has taken a lot of work to get there and a few £££££s
Just fitting the throttle bodies will mean a new programmable ECU to gain the most.
The main gain will be throttle response like a car with twin 40 DCOE Weber carbs.
Until you raise the compression, change cams and do headwork you will not be gaining much power.
My engine is still on stock rods and pistons ( Mk2.5 Block fitted with Mk2 modified head rev limit 7500 rpm)

The easy path is going to Blink Motorsport and spending your kids inheritance.
The hard path is doing it yourself ( much more fun as in my case but not much cheaper )
Do your research what are your goals what is your budget and how solid is the car you are upgrading.

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As I understand it the true raison d’etre for ITBs is to keep good drivability when you fit lumpy, big overlap cams. If you keep the standard plenum the reversion pulses cause havoc with low speed running. Changing to individual bodies means there is no interaction between the cylinders.
I believe the stage 1 Blink upgrade retains the plenum, so I guess the cams are relatively mild.
I accumulated all the kit for an ITB conversion for my 1.8 Mk1 Roadster, but never fitted it due to terminal rust. You need a lot of stuff!
Parts include:
ITBs (from a Toyota AE111)
Intake trumpets
Air filter + backing plate (difficult to get it to fit!)
Manifold (Techno Toys Tuning)
Standalone Engine Management ECU (Megasquirt)
Reprofiled Cams (Piper BP270)
Adjustable Cam Gears (CatCams)
Dual feed fuel rail
Fuel Pressure Regulator (Weber Alpha)
Vacuum Manifold Blocks x 2 (1 for brakes, 1 for MAP signal)
Maybe bigger injectors (not tested so no idea of duty cycle for goal of 160bhp)
Plus head work - skim, port clean out, valve seats
Plus rolling road mapping

Dunno. Suspect a bolt on turbo kit on light boost would work out cheaper!


Fred is pretty spot on with his summary,
I have had an MP62 charged car in the past and fancied a new challenge.
At some time in the future I will be building a forged rod and piston short block so that I can raise the rev limit above 8000 Rpm.
I can say that my current set up is not yet road registered but it drove well when I took it for the MOT test it is not quite as tractable under 2000 rpm as my stock eunos but no suprises there.
Once it came on song it was a delight.
I am stuck waiting for the staff at DVLA to sort out its registration and V5 so it is not allowed out to play with the traffic yet.

Did you fit Jenveys? At one point they were making outrageous claims for the power hike on a Mk2 just by fitting their ITB kit, but I never saw any independent before/after dyno figures.
Have recently been following the Skid Factory build of a Mk1 MR2 on Youtube. 20V Black Top with big cams and ITBs. Makes all the “dort” noises. Lovely.

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There’s little doubt that forced induction is the cheaper route Fred but, does it offer the same soundtrack or smiles?
Some prefer the gasps, whistles and wheezes of turboing. Personally I prefer the rort of natural aspiration. It’s horses for courses and definitely a personal preference thing.
What did you do with all of your kit?

Gathering dust in the spare room. Was thinking about buying another Mk1 as a track toy but I can’t face another rust saga. :frowning:
Great video about the Skid Factory MR2 just gone up. Maximum ITB gargling!


Oooh, the Precious!


Oh my! That is some nice looking equipment Fred.

Seems a shame to see it gathering dust. :thinking: