Toyotec presents...the effect of ITBs on a bone stock 16V 29/11/11

Interesting read Toyotec.

Something I've considered for my old bus at various times. Only issue for me is cost of the whole system including SEM.
I've not priced the whole lot for many years now but what ball park figure are we looking at nowdays?

I love the sound of ITB's as I remember (B6) from days of old.

I'm going to pop up to Vince at Stealth for a set up soon as it's long overdue but CFJ is in hibernation at the mo.

 

The cost for a complete 'turn key' system varies and this example is the extreme opposite to paying out where mostly everything for the exercise was resourced, researched, developed, integrated and validated "in house".

Based on various studies, I am confident a correctly selected system, along with methodical tuning, on a vehicle like yours will certainly change its character, making it a different car to drive in terms of response, drivablity and and all out power.
It will also be very repeatable as well due to electronic controls.

But...the above is all well if you have the skills and time to dial in the package. If you are paying out to external parties for services, and I can see why some folk would be justified in sticking with what they got.

 

You've hit the nail on the head.....it's all about cost and the time for the labour for an expert or a company that are capable of this type of set up.

For me the Kjet system is certainly adequate and having had knowledge of B6 there would be little gain in it's current spec v the cost of changing the whole system.

So what are the ball park figures for a drive in drive out job including all parts?

 

You should probably ask Badger Bill that question - he'll be able to supply what you need, I'd think.

 

I would say based on some of the pictures Andrew has put up recently of said car testing on a dyno system that I familiar with, improved mid range torque to begin with due to the ability to custom calibrate fuel and spark angle for the conditions.
With the correct sized throttles and lengths, as I have demonstrated in this thread vs the std inlet, you will find a reduction in torque decay in the very uppermost rpm band which will measure as greater power or axle force for those 6K rpm bends .
Overall your engine would have more torque in the midrange and then more power due to torque decaying slowly from that old baseline.
To find someone who would be willing to assess the engine as it is and for what it is, subjectively, then conduct a controlled experiment to move it to throttles and demonstrate the above would very time consuming and I imagine costly.
So if the current set up is well quick for you at the moment it may not be worth while the expense and hassle as you will be paying out.

This project was done in my spare time with assistance from other interested parties who also freely contributed their time. Their contribution was very instrumental in the creation of this write-up. I had no interest in selling the knowledge when it was written.

 

Any updates on this?

 

The car was returned to plenum setup to complete the ABF intake thread

and the Toyotec ITBs were put in storage in the Toyo-cave



personally I think he needs to have a bit of a garage sale / ebay selling frenzy

 

I see, cheers for the heads up!

Would of loved to have seen what power it was making with them!

 

You can have an educated guess if you take

the green line (forwards Gs) from the following:




which is following the torque curve from this graph:



The plenum has a peak power that give or take a few bhp lasts from 6200 to 6600 rpm
The Gs and therefore torque of the ITB setup is only slightly higher at where the plenum peak begins, 6200rpm, but then by 6600rpm upwards the torque is significantly higher.
It is probably safe to safe that the ITBs comfortably make more than 180bhp from 6600rpm to 7100rpm

 

Thanks Ben, just trying to think what my mk1 will make, I have a standard abf on Jenveys waiting to be fitted.

If it makes 180 I will be happy!

 

We never had the opportunity to test the car back to back at Garage Streamline due to time constraints and various small challenges we had with hardware leading to the track day.

Myself and Ben agreed that the dyno would only tells us the percentage increase/decrease over an established baseline. So we opted to test using the G meter instead again with a set of controlled conditions for each engine config and tune. By doing it this way Ben's other investigation on manifold lengths could validated, saving precious time.

In your case you would have to first know what baseline your engine would have before just simply targeting a number like '180bhp'. In this case we have significant data from the same dyno and one test on another of similar make to, backed up by these acceleration runs, to make an intelligent guess at what the 'number' could have been, where and why, if tested at Garage Streamline or a similar correlated source.

 

Thanks, I'll just have to wait until its in and mapped!

 

Cool. Do not get hung up on numbers unless you have good back up data. Just get it sorted to deliver the best response everywhere and what ever it reads on your local machine will be you baseline for future mods.
It is a nice looking MK1 you got there and should be relatively quick car once the once the hardware is correctly mapped.

 

Cheers Toyo, its good fun to drive as it is, I won't know myself when I fit the new stove!

 

worth pointing out bore size of bodies vs their suitability

42mm in this example..

 

Yes I did say in the opening comments it was 42mm.
In this example we worked hard on the vehicle response and was able to make the throttles work as well as the plenum calibration in terms of driveablity.
No issues on Ben's stock engine IMO. And the data we were after was captured.
For an application with that would require higher flow and possibly more output, suitability does become a good question. At what point the throttle size (and length) would compromise torque we will see on another exercise. I also got a set of 45s just incase

 

Can Jenvey Dth throttle bodies be got in 48mm?

 

Yes but make sure you have a reason to flow that much air, else you will kill off your torque on a stock motor.

 

Yes

RobT has them fitted on his 250bhp NASP Ibiza

 

As does infinity .

However RobTs is a significantly modified engine and far from the spec of murph81 OE unit.