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 Post subject: ITB discussion
PostPosted: February 15, 2020, 5:09 pm 
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Joined: January 20, 2020, 2:48 pm
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I’m investigating the reality of ITBs on the 3.4 DOHC ford SHO V8 which looks like the candidate power unit in the Type 33 build. The nature of the beast says V8 and ITBs have to be the Heart and Soul of this car. The ITBs most likely will be Kawi, Suzuki, Honda using car injectors. The TBs will go into an air box because the car will be street legal and needs to have a working PCV so the crankcase air has to go to the intake and the system needs a MAF sensor too. The 3.4 has split port intakes with a butterfly operating big secondary ports that close under 3000 rpm and over redline. The stock injector squirts under the smaller primary port. My plan is to retain the secondary butterfly system and the stock injectors and operate a second injector on top of the Bike ITBs. Both will be controlled by an ECU operating in parallel with the native PCM. PCM is needed for the street.

The unknowns are the length of the runners, TB bore and trumpets. Those are critical and millimeters matter in terms of performance. Those detail depend on cam lobe separation and duration as those create the wave that’s going to supercharge the intake air. I’m online with the SHO forums hoping somebody knows that info.

That’s where I’m at, anyone care toss in their 2 cents?
EDIT:
The SHO guys found the cam info for me and short answer the engine is cammed at a 112 LSA 215 degrees duration on both intake and exhaust valves. That got me searching for the best runner length. Then the story promptly turned full circle when I saw a conversation on the Integra Forum which asked the same questions I’m asking. A knowledgeable guy suggests the correct way to go is with a plenum to use the Helmhotz Effect for supercharging the air into the port that he says can’t be achieved with ITBs. He has data to back that up. So in my case that simplifies matters greatly by removing 8 butterflies and going with 1 TB. Still a lot of math to do but an interesting development. Now to work out the ideal runner sizes in that scenario.


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 Post subject: Re: ITB discussion
PostPosted: February 16, 2020, 7:41 am 
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It sounds like you are focused on tuning an engine you may not have for a car that doesn't exist yet.

However, it is winter and I am not working on my stuff much either. :cheers:

I suggest you get it running and driving with the stock engine. Then you have a base line to compare how much area under the curve /every day drive ability is lost with the modifications for peak power improvement.

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 Post subject: Re: ITB discussion
PostPosted: February 16, 2020, 8:34 am 
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That of course makes infinite sense, but the problem with the stock set up is packaging. The 3.4 in the SHO Taurus is a transverse mount and this build will be longitudinal. However since I’ve learned there’s other options to the ITBs. Interestingly I ve found a couple of sites, SAE Formula where guys analyised the ram effect and conclude that the Effect on a V8 is marginal, but by treating it as 2-4s it’s works well. (Holley image attached). I can build something similar using stock carbon fibre tube and mate them to the bits and pieces of the stock manifold and play with the runner lengths to find the sweet spot and building a cf plenum is within my capability. And if the tubes are vertical it’ll have the retro look the project needs

I like the remark about Winter and planning though and that’s exactly what this is about. But planning isn’t a bad thing though. When I built the LS into the 968 there was a lot of hit and miss that cost a lot of time and money so getting into the details now will pay off as it moves forward.


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 Post subject: Re: ITB discussion
PostPosted: February 16, 2020, 8:40 am 
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Just leave room above for whatever you might want in there. Seeing what is behind you is not so important with the availability of rear view cams.

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 Post subject: Re: ITB discussion
PostPosted: February 18, 2020, 12:02 pm 
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When you say that you need certain things 'for the street', like the PCV and PCM, does that mean they are required by your municipality?

Does the factory PCM operate in such a way that it can handle multiple (regardless of 2 or 4) throttle bodies? I understand that the MAF should generally be fine, but could something like the TPS running at substantially different values than expected for any given MAF reading cause it any operational issues?

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 Post subject: Re: ITB discussion
PostPosted: February 18, 2020, 2:21 pm 
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This thread tickles my fancy in a lot of different ways - I love the V8 SHO engine and would love to do something with it someday. I'm also currently adapting a pair of Hayabusa throttle body racks to a V8.

If you need a cheap, small-displacement 32V V8, the SHO is certainly an option. The 1UZ can be had all day every day for a couple hundred bucks and it's waaaay more ubiquitous. But if you don't have any of those restrictions, there are certainly better options out there. The Mustang's 3.7L V6 is smaller, more modern, sturdier, has better aftermarket support, native longitudinal (cheap!) six speed transmission, and makes 70 more horsepower. An aluminum 5.3 LS is more compact, just as cheap, likely no heavier, and I don't need to extol any other virtues of the LS family, as those are well known.

Don't get me wrong, I want to see an SHO V8 in something cool, as I've never seen anyone actually push that engine and reeeeally want to. If you're doing it because it's cool and different, you're absolutely right. But you can't get head gaskets for them at all, or intake gaskets, and other bits and pieces are drying up, so keeping the thing going will be a challenge.

I bought my 2 Hayabusa ITB racks for $70 (complete with all wiring and injectors) and $50 (minus wiring and injectors). Apparently Honda S2000 injectors will swap in place of the stock Suzuki units. Stock Suzuki injectors are in the neighborhood of 260cc - eight of them will support 400hp.

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 Post subject: Re: ITB discussion
PostPosted: February 20, 2020, 11:44 am 
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Location: central Arkansas
> 112 LSA 215 degrees duration

That's teeny-weeny smog/grocery-getter cam timing. You're not going to see any real advantage with IR.


> Helmholtz

For every point it works for you, it works against you. And it's incredibly sensitive to exhaust configuration. It's mostly useful for twiddling the stack length to get a spike in the power curve for bragging rights.

What you'll find is that IR helps low and mid-range torque when you're running a big cam, that a properly-sized plenum usually makes more top-end power, that stack lengths in the range of "what will fit under the hood" don't do much, and that the guys who write the textbooks are mostly talking through their hats. It will be a useful learning experience.

You'll still be able to realize some benefits from the independent runner setup once you put some decent cams in, but fuel injected engines are much less sensitive to IR effects than carbureted ones.

Note that if you keep the MAF system, the airbox is going to have to be very large, otherwise the induction path is going to look like an ordinary plenum and runner system to the air flow. OEM plenums range from 1/2 to 1-1/2 times engine displacement, with big advantages at 3x displacement, and still seeing benefits at 5x displacement.

I don't want to rain on your parade, but I went down that same route and couldn't be talked out of it, and I've never been able to talk anyone else out of it either. It's not a complete waste of time, but if you already have an adequate, even if not optimal, plenum intake to start with, the benefits are very small without some really rumpity cams.


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 Post subject: Re: ITB discussion
PostPosted: February 20, 2020, 2:10 pm 
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Location: Cornholio OR "Where the magic happens"
One aspect of IR intakes most focus on is tuned length.
Dr Frankenstein wanted to make a trombone intake operated by oil pressure.

But if you think outside the box,
That tuned length changes with the weight of the air, if you introduce some fuel at the top of the runner, you have effectively changed the length of the runner! 8)

However in the end, IR systems are not the magical things folks think they are, it is like drag pipes on a Harley, it is difficult to convince folks there are better solutions.
I will also urge you to consider a long runner with a plenum and a single air valve. Life becomes so much simpler then.

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 Post subject: Re: ITB discussion
PostPosted: February 20, 2020, 3:32 pm 
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Location: FL
I like the SHO, too. Enough to buy one last week with 200K and plan on a complete rebuild. It is narrower than most V8s, as it has a 60 degree "V" and a balance shaft . Chain driven cams, sturdy block and saddle for the mains. I plan on a turbo and maybe 500HP (we'll see what happens). Post your work on the engine so we can see how it develops.

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 Post subject: Re: ITB discussion
PostPosted: February 20, 2020, 5:02 pm 
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Joined: September 19, 2009, 12:33 pm
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glenbinegar wrote:
I like the SHO, too. Enough to buy one last week with 200K and plan on a complete rebuild. It is narrower than most V8s, as it has a 60 degree "V" and a balance shaft . Chain driven cams, sturdy block and saddle for the mains. I plan on a turbo and maybe 500HP (we'll see what happens). Post your work on the engine so we can see how it develops.


It's wider than any small block pushrod V8 - it's 23" valve cover to valve cover, where a Ford 302 is 19" wide. Like I mentioned before, you can't get parts for it anymore. Many of the bolts are TTY and you can't get head gaskets, so a "complete rebuild" isn't possible. Any V8 SHO engine without the cams welded is a ticking time bomb.

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 Post subject: Re: ITB discussion
PostPosted: February 20, 2020, 5:58 pm 
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All I know about ITBs is what I read, and keep reading that for all out performance, they can't be beat. But, they suck for everything else, like the other 99% of the time when you're on the street. I suggest before spending the money, do a lot of reading where people have used these on street cars and go from there.

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 Post subject: Re: ITB discussion
PostPosted: February 24, 2020, 8:07 pm 
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Joined: October 3, 2009, 1:33 pm
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Location: FL
SHO rebuild kits are available from: DNJ EK4199 Engine Rebuild Kit For 96-99 Ford Taurus 3.4L V8 DOHC 32v Cu. 207, check Ebay. My SBC is 26" across header to header, I'll have to get back to you with the width with the turbo manifolds. Let us not hijack this ITB thread. G;-)

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