4- barrel VS IR injection

[Caprimaniac]

Hi, everyone... Hope your racing season have been a success. Mine has been quite so!

Yes, it's me again. And again I want your oppinions.

As I've told elsewhere, I might leave Webers for injection. I have opted for a UK(?) based ECU: Omex 710. Sequential fuel and wasted spark EDIS using an Explorer cam sync sensor (goes in where the distributor used to be...).

Let's say the engine will go full race. Curcuit. Asphalt. (Or maybe not. A street/ race combo is still where I am. Although planning a race car "in my head".)

Should I go for a 4- barrel 1000 CFM throttle body with port- injection, EDL-29285 manifold, or a 4 x IDF throttle bodies w/injectors in barrels & an Inglese IDF manifold?

According to A. Graham Bell's book "Four- stroke performance tuning" (3. ed. 2006) in pages 161 & 163, a setup with 4 x 48mm IDA TB's (1) did make the following power compared to a Vic jr. manifold w/ 1000 CFM 4-b TB (2):

RPM Hp(1) Hp (2) Torque (1) max@5500 378,2
4500 284,9 284,8 Torque (2) max@6000 368,5
5000 311,5 315,0
5500 396,2 378,4 About the same below (1) consistently higher
6000 425,3 421,0 above.
6500 454,5 441,8
7000 439,6 431,3
7500 424,8 400,6

(Hope this comes out OK) All other components are supposed to be identical. (He also have a OE Mustang FOX manifold and a Vic Jr manifold with 750 CFM Holley in this comparison.)

I think (therefore I am): 4- barrel +'s: simpler, less hussle, port injection (?).

IR +'s: Sligthly higher Hp and torque; significantly I'd say? Maybe better throttle response? -'s: More fiddling about & more things can go wrong.

Let's hear what you racers have to say.

RuneS.

[Gaz64]

Rune,

The only advantage the plenum manifold will have is you have no linkage balance issues to contend with.

Of course you'd be used to carb balancing, so should be a walk in the park.

With an IR manifold, you would set the throttle blades all at 1/8 turn open, and with interconnecting plumbing for idle air control the cylinders should balance out.

With a plenum manifold, you're limited for injector placement, where as an IR manifold you can have the injectors anywhere, right back above the trumpets makes most power.

If cost is not really an issue, I'd go for a crossram IR manifold, 50-55mm throttle bodies, with the injectors outboard of the trumpets within their own airbox per bank.

[vector1]

don't know your engine setup but i have a complete accel dfi setup collecting dust....

[philminotti]

You didn't mention what scheme your system uses to determine air charge, ie: mass air flow sensor (MAF), speed density (MAP) or alpha-N. Assuming it's not MAF (because MAF would be overwhelmingly complex and ridiculous on a stack system), keep a couple of things in mind. Speed density systems require a manifold absolute pressure sensor. This needs to be a common plenum. So, with a 4 barrel throttle body, the MAP sensor is just a tap off the intake plenum. However, for a independent runner system, all the independent throttle body vacuums need to be mechanically averaged in a common plenum. This can be done, and there are several people on this site who have nifty systems fabbed up underneath the intake manifold. My opinion is that these complex plumbing systems generally result in a rather noisy MAP signal, although like I said, that's just my opinion. With an independent runner system, I think using an alpha-N scheme makes far more sense. The ECU calculates air charge based solely on RPM and throttle position. It's not so much fun to tune, but once dialed in, it works well.

I opted for a 4 barrel system.

Hope this helps.

phil

[bobcowan]

8 stack MAP is easy. Buy your intake manifold from Wayne Presley, and it's already built in.

IR systems can be a bugger to tune correctly. But once you get the hang of it, it's not a big deal. And they look just great. When properly tuned you get a nice flat torque curve that's real easy to drive on the track.

Maximum power from a maximum build engine will come from a large 4 barrel TB. That big plenum underneath gives you a better fuel charge.

I love my IR system. The look, sound, and power is just awesome. But if I want more power, that would have to go.

[philminotti]

I agree that 8 stack MAP can be easy. But this is definitely engine dependent. If you have a big, large overlap cam like most of the big inch big block folks have, you can get a decent size reversion pulse back through the intake runner, thus my comment about a noisy MAP signal. I suppose that if thought is put into cam selection for an IR system, this might not be an issue.

[Caprimaniac]

Hmmm. Not really convinced yet.

Think of running Alpha-N, but might also try with MAP- sensor. If interconnected plumbing is needed (I wouldn't think so?), I suppose you use tubing to connect all 8 runners from somewhere below(?) the butterflies into a common box or whatever (and that's it?). That would be where the MAP sensor would go.

When it comes to cam, I would go with quite wide lobe separation, 110 +, but there will be quite some overlap- I would guess it wil have a RPM band to 7500 or 8000.

The ECU will be of a newer model... Will run wasted spark with 2 x 4- towers and seqential injection.

I'm not sure about this: "Maximum power from a maximum build engine will come from a large 4 barrel TB. That big plenum underneath gives you a better fuel charge. " When I think of it, yes- OK- if you bulid a max Hp engine of a certain volume/stroke etc- let's say a a 800- 1500 Hp 347 drag engine, it might be so.

But let's take these facts into account:

Fullrace/ HO 4- cylinders run IR (for instance Cosworth roller barrel setups- 300 Hp and 2 litres 9000rpm?)

Throttle bodies are also popular with high output turbo- engines. (600Hp+ 4- cylinders.)

Should we assume no difference in throttle response and not very significant difference in Hp/Tq between a 4- barrel and IR?


Now I will look into crossram manifolds. Have seen them available from somewhere- athough I cannot remember where. (With a new manifold I could keep my Weber setup on a roadcar!)

Thanks for the input. Need more to be convinced!

[Caprimaniac]

Found some interesting things at the GT40 forum Cross ram intakes - Page 2 - GT40s.com Good reading, some of it.

It also seems like Moon (and also Inglese, but only as a complete package) has a croosram manifold that supports DCOE carbs/ TB's.Mooneyes Online Store - Specialty Equipment Manufacturer, Speed and Custom Parts for Motorcycles and Automobiles

How would one of those work with 50mm TB's? Are the runners too small to support 600 Hp? The downside with this type of crossram is "how to get cold air into the throats"..? Two boxes and tubes from the front area is the sollution I can see...

Ok; let's have a look at those Aussie race- intakes.... Look great, work great- but the cost is 6000$ or so.

[bobcowan]

Originally Posted by Caprimaniac

Hmmm. Not really convinced yet.

Not really convinced of what?


Think of running Alpha-N, but might also try with MAP- sensor. If interconnected plumbing is needed (I wouldn't think so?), I suppose you use tubing to connect all 8 runners from somewhere below(?) the butterflies into a common box or whatever (and that's it?). That would be where the MAP sensor would go.

As I said, Wayne Presley sells a manifold that has the plenum built in. No mods needed. If you have a manifold that doesn't have the plenum built in, you can do just what you're thinking. it looks like this:


When it comes to cam, I would go with quite wide lobe separation, 110 +, but there will be quite some overlap- I would guess it wil have a RPM band to 7500 or 8000.
Yes, that really is the key. You can run just about any "size" cam you want, in regards to lift and duration. But the wider LSA really works well to prevent the reversion.
Inglese sells cams specifically for Webers. And Comp Cams (who now owns Inglese) makes Ford stroker cams with a wide LSA. I can tell you from experiance that those cams really do make a differance

The ECU will be of a newer model... Will run wasted spark with 2 x 4- towers and seqential injection.
Easy to do with off the shelf products. I'm considering updating my ECU to something similar. I'm also consider coil-on-plug systems, with a crank trigger.

I'm not sure about this: "Maximum power from a maximum build engine will come from a large 4 barrel TB. That big plenum underneath gives you a better fuel charge. " When I think of it, yes- OK- if you bulid a max Hp engine of a certain volume/stroke etc- let's say a a 800- 1500 Hp 347 drag engine, it might be so.
Well, I'm making somewhere around 630'ish hp - 510 on the chassis dyno. I'v discussed this with Gordon and Wayne both. To make more power, I would need to go with bigger heads. But, bigger heads won't match the IR system - tried that. For bigger heads and ports, I need a common plenum. Speaking from experiance, not theory. YMMV.

But let's take these facts into account:

Fullrace/ HO 4- cylinders run IR (for instance Cosworth roller barrel setups- 300 Hp and 2 litres 9000rpm?)

Throttle bodies are also popular with high output turbo- engines. (600Hp+ 4- cylinders.)

Should we assume no difference in throttle response and not very significant difference in Hp/Tq between a 4- barrel and IR?


Now I will look into crossram manifolds. Have seen them available from somewhere- athough I cannot remember where. (With a new manifold I could keep my Weber setup on a roadcar!)

Thanks for the input. Need more to be convinced!

Originally Posted by Caprimaniac

Found some interesting things at the GT40 forum Cross ram intakes - Page 2 - GT40s.com Good reading, some of it.

It also seems like Moon (and also Inglese, but only as a complete package) has a croosram manifold that supports DCOE carbs/ TB's.Mooneyes Online Store - Specialty Equipment Manufacturer, Speed and Custom Parts for Motorcycles and Automobiles

How would one of those work with 50mm TB's? Are the runners too small to support 600 Hp? The downside with this type of crossram is "how to get cold air into the throats"..? Two boxes and tubes from the front area is the sollution I can see...


Ok; let's have a look at those Aussie race- intakes.... Look great, work great- but the cost is 6000$ or so.

Remember the movie, "Corvette Summer"? Remember the hood?

[cobrarkc]

Originally Posted by Caprimaniac

Found some interesting things at the GT40 forum Cross ram intakes - Page 2 - GT40s.com Good reading, some of it.

It also seems like Moon (and also Inglese, but only as a complete package) has a croosram manifold that supports DCOE carbs/ TB's.Mooneyes Online Store - Specialty Equipment Manufacturer, Speed and Custom Parts for Motorcycles and Automobiles

How would one of those work with 50mm TB's? Are the runners too small to support 600 Hp? The downside with this type of crossram is "how to get cold air into the throats"..? Two boxes and tubes from the front area is the sollution I can see.

Ok; let's have a look at those Aussie race- intakes.... Look great, work great- but the cost is 6000$ or so.

Do you mean these?
/MorrisonOz/Products

[Caprimaniac]

Not convinced to choose one above the other.

Nice hidden plumbing In Wayne's manifold. I'd rather have it up in the daylight, you never know when there's a leak.

Never saw "Corvette summer" I'm afraid. Although "American Graffiti" is on my shelf...

Yeah, yeah. Morrison is one. There's a couple of others. The carbon trumpet manifold I think was used in OZ V8 series as well. I think 8000$ or so. Not in my league, I'm afraid.


OK, Bob. We agree, then at one point "To make more power, I would need to go with bigger heads. But, bigger heads won't match the IR system - tried that. For bigger heads and ports, I need a common plenum. Speaking from experiance, not theory. YMMV." : High rise 4- barrel for max Hp. But: how will the switch from your 8- runner to 4- barrel affect your Hp and torque curve (not the maximum reached), and would the driveability of the veichle be altered in any way?

The curves you posted in the IR bore size- thread shows up steady rise & flat at the top. Would a 4- barrel show flat, flat, very steep & a peak?

[bobcowan]

Here ya go, Corvette Summer

The picture I showed above is not from Wayne. I bought that one from Blue Thunder, and then Momar Injection added the vacuum plenum. The one Wayne has is much better, with a cleaner almost fail proof plenum. That's what I use now.

I think the IR system creates a flatter torque curve with better throttle response. Compared to a 4 barrel carb or EFI with a carb type intake manifold you would lose some power. That's a tough call, though. If I switched to EFI with long runners and a large central plenum, I think you would lose a little bit of bottom end, but not much. And you'de gain a bunch more power at the top. You might even lose a little bit of throttle repsonse in the lower rpm range. That would be something like a Victor manifold with a 1,200 cfm throttle body and port injection. That would work, but the torque curve would probably not be as flat.

But, I really like the way this EFI system looks. It makes me happy when I open the hood, and it makes me laugh out loud when I mash the throttle. I'd like a bit more power, but not willing to lose the looks. Life's full of trade offs.

Remember that the weber 4 barrel systems were used in race cars in 60's to make more power at the upper rpm range. And that was on much smaller engines. Trying to feed 427 cubes making 650hp at 7,000 rpm is tough. That's an uncommon demand, so there's not a lot of off the shelf parts available that are affordable. How many people do you know that regularly race a 427 stroker?

[Caprimaniac]

Wow; some kind of a cold air intake on that Vette!
Mean machine, that's for sure.

I guess we're kind of converging at some point here now..... Larger volume cylinders might be choked by the small runners. I have followed Jac Mac and
and others discussion on the theme. One thing I do not understand is that alot of people say their engines run out of steam at low RPMS like 5- 6000. OK; in my 347 I have no problem spinning the engine, working uphill to 8500 rpm + with 48 carbs and 40,5mm chokes. And I have neither any problems spinning my 3- litre V6 to 7500 rpm + with 40mm carbs and 34mm chokes.

I clearly see you'll need vary large runners & TB's (52 mms) too support a 9000 rpm 427. and I'm 100% convinced that a 50 mm TB would support 600 Hp on a 347. (Not that I'll go that far....)

Anyway. How about:

+
TS body 40-50mm Pair - Jenvey Dynamics
+
Air Horn tapered 51mm x 83 - Jenvey Dynamics?

The manifold is supposed to support 50 DCOE webers.

What concerns me is the way they have curved the runners to make them clear a distributor. Not good. I would also prefer the runners to come more straight out of the heads and not slope downwards or horisontal, that is.....

I'd choose a manifold like this: 350 Chev V8 Cross Ram Setup - 350 Chev V8 - Engine which is also has a fair price of 3800$

As far as I have found the only option for a SBF showing these characteristics is the Morrison crossram injection system, which come out at double the price.

My question now is: Do anybody have any experience with this Moon inlet manifold?

And what would you think of the setup I've figured out above?

[Dimis]

Originally Posted by bobcowan

Here ya go, Corvette Summer

Sorry, but that's one of the ugliest car I've ever seen

[Caprimaniac]

For those of us who grew up in the 70's, this car is 100% spot on what was considered a hot ride back then. Today, I would never built my car like that, no. For nostalgic & historic reasons, if it was built in this period, I would not be embarrased to show up in a ride like that.

I was going to post a pic of a 70's Capri, but I couldn't find any. It's glossy candy apple red flake colour, rised rear end and a fox tail in the tall rear antennae. Built in the 70's, still visiting shows in 2010....

Off topic.

Now on topic.... However hard I try, I cannot find anyone using that Moon crossram SBF manifold. I've been talking to Moon, and they have the piece in stock.

I'm not the only one asking for info on this piece, Rick is asking here -=NEW=- SBF 289/302 Weber Crossram and that was back in 2006.

Someone please come up with some info????

(I just got my eyes wet by thinking of using short 40mm carbon trumpets atop of these 30mm badies on the moon manifold....)

[bobcowan]

Originally Posted by Caprimaniac

(I just got my eyes wet by thinking of using short 40mm carbon trumpets atop of these 30mm badies on the moon manifold....)

Your eyes?

[Caprimaniac]

Ehe... Maybe some other body parts as well; I'm so excited. Paralyzed....

[Caprimaniac]

Well. For those who's interested I now have lots of pics and details on the Moon crossram manifold for the 302.

I can post it here if someone is interested.

Let's see how this setup looks like (I've omitted the carbon trumpets because of reasons mentioned above...):



The distance from the butterfly and injector to the valve head, the distance is 13".
The spray direction from the injectors have been added. Spry pattern has 15% sread to each side (not in drawing).

How will this work: cold start and idling? (At WOT, it will hopefully work very well, uhu?)

RS

[Gaz64]

Rune,

I like your idea with the injector, but I would lay it over to aim at the centre of the runner rather than the floor.

Is that using the 30mm (thickness) Jenvey throttle bodies?

[Caprimaniac]

Hi.

Yeah, Gaz- that's the Jenvey 30mm's.

The injector angle is fixed on the bodies. The picture of the manifold has some distortion, and the angles are not 100% correct. I have tried to extrapolate to put the bodies on the manifold as they will be in the real world.

Therefore, I cannot alter the direction of spray. And that is one of the concerns....!

But let's have a look at another drawing. This is the Inglese IDF manifold with throttle bodies. This is even worse, yes?


I do have the possibility, though, to buy an IDF maniolfd and bolt on the reverse plates..... Is there someone who've tried this on the 302 and found enough room between the TB's for fuel rails????

RS