ITB's on 8V

[nyabinghi]

Hi,
I can see a lot of 16V engine (c20xe, c16xe...) with ITB's or a lot of 8V with carbs. Why not a C16SE or E16SE with ITB's ?
Do you think it will be better than carbs ?

Thanks

[craig green]

It ought to be, but the general opinion is that the 8v engine does not offer a wide enough power band to make full use of them. However seeing as the TB's are always accompanied by a mappable ECU, it ought to be mappable to be nice & driveable. However I guees the 16v heads can flow far more air & make much more economical sense bhp per ?.

I knew of a Nova hot hatch race car some years ago that ran a 1600cc E16SE with TB's & was pushing out 189bhp. That car won its class 2 years running & the owner went on to continue winning the class in the 1.6XE Corsa he built afterwards.

[Stuart]

its largely to do with gas speed. With 8v engines the gas speed simply isnt high enough to warrant a 40mm TB fully open... you get T40 DCOE's but they are choked down to 34mm etc.

[Adam]

ITBs will be fine on a 8v, if you can find small enough ones.

[nyabinghi]

OK,
Thanks for your replies.

My idea is to build a C16SE with MegaSquirtII and a non-common setup.

I was first thinking about a 1.6l turbo, but since mvaux.com have closed I can't find custom-made forged piston for 1.6l at a good price and I have a limited budget.

That why I'm interesting in a C16SE with ITB's with a home-made inlet manifold and bike throttle bodies, so I think this kind of setup isn't too expensive.

As you say, a 40mm TB may be too big for the 8V head flow, so I have to find the bike which has the good TB size, let says 34mm what do you think about this ?

[Adam]

Yeah, id go with about 34mm. Might be difficult to find tho as most bikes are 38mm+

[Nick]

If you look around, there a plenty of people who build 8v race engines on TB's !

But, in terms of this site.. it's not common practice at all ! For the reasons above.

[craig green]

Might aswell use a 16v head & have another 30-40 bhp or even more.

Only costs are the base engine & potentially another camshaft 8 lifters & followers etc.....

[meritlover]

i have to respect your wishes to take the time to craft a manifold and use the throttle bodies to get the engine you want.
a lot of time it is not common practice because most consider the time,money and effort compared to doing a x20xe swap (which can be done in an afternoon) and write off the idea of doing a 1600 properly.
it would be fair to say that if courtney offered a bolt on kit for so many so called 'nova tuners' there would be hundreds of fast 1600s around on our wonderful roads.
yes on a std 8v the torque curves do not merit the work, however with tuned length runners, intake trumpets, exhaust manifold length, cam timing lift and duration, all these things can be altered to gain power more effectively. and increase the 'gas speed' that seems to concern so many text book tuners.

most would be feared at the prospect of even converting an SRI or GSI to a megasquirt....which would be probably be the most sensible first mod of all!!

i wish you well with your project and have pictures of home made manifolds that may be of a help to you.

happy nova tuning!!
please be happy.

[Stuart]

lmfao you of all people are a text book tuner/talker ;)


yes race engines have been seen on ITB's but thats mainly due to the fact the live at 7.5Krpm + all the time and can justify the ITB's, but for road use I cant imagine them to work at all well unless you sleeved them down to something like 34-36mm

[meritlover]

oh mr Stuart. its so clear you dont know me. lol
he didnt ask if large throttle bodies would be rubbish. it was clear that if the right size throttles were found then it would work well. you even say yourself that 34-36 mm butterflies are ideal. therefore if he obtains the correct size....then he will have a good engine. nor was there any mention of whether it was to be used on the road/track/rally or other.

do not feel threatened by me stuart. i do not mean to intimmidate you.

please.

[mikey14sr]

mmm, any 400cc bikes running on fuel injection I wonder? If so, they might be around 34mm? (based on the observation that 600cc tend to have at least 36mm choke sizes).

[meritlover]

correct Mikey now your thinking outside the box, contrary to what Mr stuart says. i can vouch for thae fact that they work very well when set up properly ;)

[Stuart]

lol oh how little you know me too ;)

odds on you could get 99% the same results with tuning the std inlet manifold + aftermarket ecu compared to the hassle of sourcing and fitting correctly sized ITB's

[nyabinghi]

Might aswell use a 16v head & have another 30-40 bhp or even more.

Yes that's right but for me 16XEs are not known for their reliability



Only costs are the base engine & potentially another camshaft 8 lifters & followers etc.....
You put the finger on : this involve that I purchase an engine which price is higher than the C16SE price. The rebuild of a 16v is more expensive too.

At the mo I have a stock 20XEJ in my nova, I want to sell it to go back to a small block with about the same power (140-150) and a non-common particularity. I know I will never have the red top torque with a non turbo 8v.

[craig green]

Theres no reason why you cant go ahead & do it (TB's on an 8v).

It just makes no sense. Keep the 2.0 XE unless the understeer has finally done your head in.

[nyabinghi]

odds on you could get 99% the same results with tuning the std inlet manifold + aftermarket ecu compared to the hassle of sourcing and fitting correctly sized ITB's
This sounds right.
It seems that the ITB sizing will be a problem, and I don't have the knownledge to choose them correctly.

If I can't find small ITB and I don't find anyone to help me choosing them I will go for a C16SE with cams and megasquirt. Simply.;)

Thanks for your replies :thumb:

[craig green]

Good thread.

[Adam]

Yes that's right but for me 16XEs are not known for their reliability

Since when?

[mikey14sr]

I know thw earlier C16XE were known for having under-sized rings, but that's as unreliable as I've heard about them.

[Adam]

Aye, most were sorted under warranty anyway.

[Mike]

odds on you could get 99% the same results with tuning the std inlet manifold + aftermarket ecu compared to the hassle of sourcing and fitting correctly sized ITB's

Agreed, the standard inlet manifold is identical to that used on the Group A rally engines, therefore adequate enough for use on a 150bhp ATF engine, coincidentally that was a boggo inlet setup with aftermarket management too.....

Leads me to beileve whats quoted above also....

[mikeoxford]

At the mo I have a stock 20XEJ in my nova, I want to sell it to go back to a small block with about the same power (140-150) and a non-common particularity. I know I will never have the red top torque with a non turbo 8v.

I disagree. I know both myself and Dan (apart from transmission) ran very similar engine spec and were pushing 140BHP+. Jim managed to push the boundaries even further and saw some phenomenal results for both power and torque from an 8v engine.

However, im not about to start another big block small block debate, each to their own :thumb:

[Nick]

Do the E16SE.. they're great !

I'm probably the most indecisive person ever, and i'm never content with anything... But i don't think i'l be changing it for a 16v in a long time !

Again, As mike said.. this isn't a Small/Big block debate.