20 replies to this topic

[mariner]

Again from engine labs website an add on but a neat way of giving some benefits of FI without a whole new harness, sensors, and a  high pressure pump system.

 

https://www.enginela...ol-reliability/

 

If you already have fuel regulator in your Holley or whatever fuel lines install is mainly the wide band O2 sensor.

 

 

[Greg Locock]

So this is a low volume throttle body injector, in series with the carb, controlled by a wideband O2 sensor.

 

K&N.

[mariner]

Basically YES.

 

It is obvously not perfect but it has several posible benefts fro somebody using big Holley like the 850cfm. They are great for dumping in fuel at full throttle but poor at slow road speeds etc. 

l

If you jet the Holey down a bit you should have injector control over a  wide rang of mixture e, remembering it can only add fuel not subtract it.

 

To make Holley work n road/corners you need a pressure regulator set at about 6/7 psi so a suitable fuel supply to this thing is available  next to tthe carb.

 

there is one other possible benefit for  road racing/track days. he Holley doesn't like side G too much so mixture can vary through a corner. If this thing can react rapidly it could kept the mixture spot on for less risk of weak mixture and cleaner pick up out of corner.

[Wuzak]

So why not go to one of the throttle body injection systems?

 

I believe the Holley system has the ECU in the throttle body unit.

[Kelpiecross]

  The story doesn't say - but I presume part of the idea is to give the visual impression of a carburettor engine  on a classic car - but with the advantages of FI.   SU apparently have a full FI system hidden in a SU carb.  to suit classic cars.  Maybe they should have a full single-point injection system hidden in a non-working Holley or similar.    

[Wuzak]

That's the point of the throttle body injection systems, such as Holley's Sniper and Terminator Systems.

 

https://www.holley.c...ion/sniper_efi/

https://www.holley.c...terminator_efi/

 

And similar systems from FiTech

https://fitechefi.co...go-efi-systems/

 

And probably many others.

 

Then there are port injection manifolds which are based on carburettor style manifolds (like those used in NASCAR)

https://www.holley.c...s/parts/300-260

 

Which can be fitted with a carburettor style throttle body, or even be adapted to a fly-by-wire throttle.

[Wuzak]

Reading the article again, it seems the system does not need a fuel system upgrade, whereas the EFI systems need a higher pressure pump.

[mariner]

The main attraction is  closed loop mixture control at low cost. Summit racing sell the kit for USD 499.

 

https://www.summitra...-0001/overview/

 

 

In contrast the Holley TB fuel injection kit is USD 2,100 plus a high pressure pump for another USD200.

 

https://www.summitra...0-406/overview/

 

So it is less than 25% of TB FI for a V-8. The TB EFI is  likely to be better but none of the TBI systems offers individual port delivery and if you run a single plane manifold with a carb., TB EFI or the now K&N thing fuel distribution will not be ideal.

[Wuzak]

~650hp Holley Sniper for ~US$1300 with fuel system

https://www.holley.c.../parts/550-511K

 

~US$1000 without fuel system

https://www.holley.c...i/parts/550-511

 

 

US$925 for the fiTech 600hp TBI

https://www.summitra...30002/overview/

[mariner]

Those systems are cheaper than the Holley one above which is great but , as best I know, they all rely on a handheld tuning box and are not PC compatible which, again as I understand , the K&N thing is.

 

I'm not sure if the PC link is essential but it does give wider possibilities.

 

BTW there is really nice FI system  built into a dummy Weber 40DCOE available . from Jenvey, a well respected UK FI company. You have to look really hard to see its not a Weber and it's great for  Lotus twin  cam engines which had a  habit of dripping fuel onto the distributor beneath and catching fire!

 

By the time you have bought an ECU and sensors the cost is  about £3,000 to install it.

 

https://store.jenvey.../heritage-dcoe/

[Wuzak]

Apparently the FiTech system can be tuned with a laptop, as with the Holley Sniper system.

 

Though I have seen one video where an Chevy LS engine was fitted with the Holley TBI but controlled with an aftermarket ECU.

[gruntguru]

Reading the article again, it seems the system does not need a fuel system upgrade, whereas the EFI systems need a higher pressure pump.

No doubt this needs some minimum pressure value for adequate atomisation. Continuous pressure would be essential too, so fI don't think I would like to use an old cam and lever mechanical pump or even an impulse type electric pump.

Edited by gruntguru, 03 April 2019 - 03:54.

[Wuzak]

A while ago I considered making a thread about fuel injection vs carburetor, which is better?

 

What started me thinking about this was a video showing a Comaro Sports Sedan breaking teh Sports Sedan lap record at Bathurst during one of the "combined sedans" support race at the Bathrust 12h, 2018.

 

https://www.youtube....h?v=v90h0LatFbw

 

I thought the car sounded a lot like a NASCAR, so I looked up the rules and found that the NASCAR engines are, indeed permitted. By the shape of the engine cover this one looks to be a carburetted version, the car having being built around 2012.

 

In contrast, some of the other NASCAR powered Sports Sedans are fitted with multi-port fuel injection with individual throttle bodies. Such as John Gourlay's Audi/Chev Sports Sedan, driven by Jack Perkins.

 

https://www.youtube....h?v=lr_aqqxmwP8

 

So I looked around for direct comparison videos, where an engine has been dynoed with both.

 

This one shows small gains changing from carbs to EFI, the intake system being from a big bike can support more power.

https://www.youtube....h?v=aj-Z33MO2Gk

 

While this one shows a small loss

https://www.youtube....h?v=3Zj0RMPKquw

 

Obviously the question is always "which one makes more power?". But isn't that question like "how long is a piece of string?".

 

If you put an EFI system that flows less air than the carburetor it replaces, it is most likely to make less power. And if it flows more, then more power can potentially be made. Assuming the fuel injectors are big enough to support that power.

 

The second video is a FiTech TBI system. The base model of that is rated for 400hp, so could the loss of power be explained by it being at the upper limit of its air and fuel flow capabilities?

 

Would it be fair to say that the advantages an EFI system has over carburetors are not the peak power side, but more on the low/mid range area of the power curve and fuel economy?

 

And finally, has the carb vs EFI question been settled? Obviously almost all petrol cars sold today have EFI, but many of those have been converted to carb for racing, and there are still a lot of carburetor proponents.

[kikiturbo2]

there is no advantage with carbs.... They can be optimised around a single load / RPM, so should be good for max power... .rest of the time you are just wasting fuel...

 

Why is it used on some race cars... well in amateur racing you have a couple of issues... First, not anyone can map a EFI, and for some people it is easier to fiddle with carbs... also those look cool and when you have single carb throat per cylinder it just looks like it will make most power. Multi throttle body injected intakes are also very expensive... lots of people experiment wuth bike intakes for that reason.. Also, amateur racers seldom log and experiment to see if they actually made gains..

[Kelpiecross]

  The carb. always has the basic disadvantage that it must restrict the air flow a little though the venturi - otherwise it doesn't suck in any fuel.  Clearly EFI needs no restriction.

 Carbs certainly can look magnificent. An example is the three 2 inch SUs (especially when polished) on an XK/XJ type engine.   But it is notable that the incredibly untidy-looking  EFI on the Type 3 XJ6s actually makes quite a bit more power than the three SU types.    

[GreenMachine]

As someone who has looked at the tuning of an after-market ECU, the range of variables that can be accommodated in calculating when and how much fuel is needed seems pretty conclusive (not to mention ignition timing).  Assuming accurate/reliable sensors, and competent (preferably expert) tuner, the ECU must provide a better tune across a wide range of operating situations.  These days this includes the ability to make, on the fly, big changes to fuelling and ignition tables to allow switching between tanks of petrol and E85, the latter much favoured in boosted engines but not always available in all areas.

 

Certainly there is a lot more complexity, and therefore a lot more that could go wrong - having spent a fair bit of time (money) chasing a degraded tune on the dyno, before finally locating the failing temperature sensor, this was an uncomfortable reminder that there is a price to be paid for the enhanced performance.

[Wuzak]

A Coyote converted from EFI to carb and then back again.

 

https://www.youtube....ch?v=TgFpjQzeC28

 

https://www.youtube....h?v=l-NZIOIhUiU

 

The carb set up could not control the VVT, so it had to be set up as a compromise. Once the engine wwas hooked back up to an ECU it again had VVT, which helped with low down performance.

[Lee Nicolle]

A while ago I considered making a thread about fuel injection vs carburetor, which is better?

 

What started me thinking about this was a video showing a Comaro Sports Sedan breaking teh Sports Sedan lap record at Bathurst during one of the "combined sedans" support race at the Bathrust 12h, 2018.

 

https://www.youtube....h?v=v90h0LatFbw

 

I thought the car sounded a lot like a NASCAR, so I looked up the rules and found that the NASCAR engines are, indeed permitted. By the shape of the engine cover this one looks to be a carburetted version, the car having being built around 2012.

 

In contrast, some of the other NASCAR powered Sports Sedans are fitted with multi-port fuel injection with individual throttle bodies. Such as John Gourlay's Audi/Chev Sports Sedan, driven by Jack Perkins.

 

https://www.youtube....h?v=lr_aqqxmwP8

 

So I looked around for direct comparison videos, where an engine has been dynoed with both.

 

This one shows small gains changing from carbs to EFI, the intake system being from a big bike can support more power.

https://www.youtube....h?v=aj-Z33MO2Gk

 

While this one shows a small loss

https://www.youtube....h?v=3Zj0RMPKquw

 

Obviously the question is always "which one makes more power?". But isn't that question like "how long is a piece of string?".

 

If you put an EFI system that flows less air than the carburetor it replaces, it is most likely to make less power. And if it flows more, then more power can potentially be made. Assuming the fuel injectors are big enough to support that power.

 

The second video is a FiTech TBI system. The base model of that is rated for 400hp, so could the loss of power be explained by it being at the upper limit of its air and fuel flow capabilities?

 

Would it be fair to say that the advantages an EFI system has over carburetors are not the peak power side, but more on the low/mid range area of the power curve and fuel economy?

 

And finally, has the carb vs EFI question been settled? Obviously almost all petrol cars sold today have EFI, but many of those have been converted to carb for racing, and there are still a lot of carburetor proponents.

The Camaro is a carb LS engine. As was Kerry Baileys Jag a year or two ago. 

No Sports Sedan can use a Nascar engine, It must be stock block and Nascar engines ceased being that along time ago. Might I add nor is Supercar Chev engine.

The Audi is an efi multi throttle body SBC.  With the gearbox attached. Good car driven very well by Jack.

A 4 barrel manifold with a 4bbl throttle body and 8 injectors works quite well If sorted properly. No real power gain over a carb but usually a bit cleaner in operation

As for fuel surge in a Holley? Sorry with the right carb it does not happen. On the very odd occasion very rough roads may effect them but sort the needle and seat and float weight problem solved. And all with 7lb of fuel pressure [9 on methanol] not 60 which creates its own problems. And is far more dangerous in a crash. Or even with simple fittings come off.

But look at Speedway Super Sedans or late models or V8 Dirt Modifieds. Or even many offroaders. Rough tracks with big HP engines and no fuel surge. But efi without surge tanks etc does have problems. And factory style throttle bodies are less than satisfactory as well Leave those for the tubo drag racers!

[Lee Nicolle]

A Coyote converted from EFI to carb and then back again.

 

https://www.youtube....ch?v=TgFpjQzeC28

 

https://www.youtube....h?v=l-NZIOIhUiU

 

The carb set up could not control the VVT, so it had to be set up as a compromise. Once the engine wwas hooked back up to an ECU it again had VVT, which helped with low down performance.

35hp with a different manifold , efi, and a different dyno! Yeah right really equal!!

With that huge fabricated manifold it will never have bottom end. And it would only be good for drag racing. 

Efi and VVT helped bottom end maybe.  But totally unrequired for Drags where you leave at 3500 up and turn [on that engine] 8000 as it fell on its arse over that. On either system. Though the cams were a bit small even for that. I used similar lobe seperation and degrees on my low buck  SB Chev and made similar power as well. From 5850cc of 2 valve Chev designed in 1954!!

BUT an engine with all those very unreliable chains and quite heavy, worse top heavy compared with the LS Chev or Mopars.

Good road car engine, something Ford have generally done but not good for modification. 

The F5000s that may eventually hit Aussie tracks I feel are going to break chains regularly unless they limit them down to say 7000.

[Wuzak]

The Camaro is a carb LS engine. As was Kerry Baileys Jag a year or two ago.
No Sports Sedan can use a Nascar engine, It must be stock block and Nascar engines ceased being that along time!

The rules require stock block, except for specified NASCAR engines and those approved for V8 Supercars

The Audi-Chev and Saab-Chev do have NASCAR engines

[Wuzak]

But look at Speedway Super Sedans or late models or V8 Dirt Modifieds. Or even many offroaders. Rough tracks with big HP engines and no fuel surge. But efi without surge tanks etc does have problems. And factory style throttle bodies are less than satisfactory as well Leave those for the tubo drag racers!

Maybe it’s because the fuel system was designed for that