Throttle bodies vs carbs

Just thought I'd quote this from the other site where Skiddy's been posting :

"if you are looking for an expensive mod to literally knock like 2 seconds off your 1/4 mile time, a custom intake manifold and fuel managment is where its at. i still cant believe the difference in power this thing makes....im going to go sit in it now

**im not even going to post the cars ive whooped in it since i got her running
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1976 280Z 2+2 with: fully rebuilt performance engine, all new performance suspension, and a sexy 19yr old driver...running a sub 14 second 1/4 mile, NATURALLY ASPRIATED and no NOS...har har har *cough* custom EFI manifold and SDS *cough*

"Yes laides, you can ALL fit in my 2+2""

Should keep Grolls happy ! And Grolls, if you see more than 200 bhp, I'd be surprised - like I said earlier, you'll need at over 250 bhp to even try and match Steve !

Rob, sorry, casually meant traditionally, as in Grolls engine and most 2.8s running on triples on the roads !

Steve, as I said previously - accepted mate, but for bhp / £, triples are still the leader but I'll generously concede :)-) that TBs deliver a smoother response all through the rev range with potentially a better fuel economy (can you give us some figures for mpg ?). Personally, I have no problem with the look, I'm no purist Count, and I think if the science can be brought down in price, they will be the future.

BUt before all that, people'll have to know what else needs to be done engine wise to get the most out of the TBs and that, you're not willing to share ---at this moment :) for reasons I can well understand and accept !

You've done all the hard work, investment, time etc, no reason to share that without some return !
Who're you choosing to work with to market the next range of super S30s ?
 
Carbs have made there mark in the history of motor cars,they have been
versatile in their requirements.
Throttle bodies,are still in the development stage,If they achieve the
longevity that carbs have achieved then,that will be a good thing.
2+2's,260's are mentioned,due to them being portrayed as none
entities or non-existant in the modification stage. A case of:
"My bike has more gears than yours".
Are Throttle bodies just being developed for the quarter mile or do
they have use elsewhere?
Sometimes (especially on the quarter mile & on the straight) extra
weight might be an asset Its about Thrust & velocity.
Weight alone cannot be argument to fail,( i.e Bluebird) that weighed
more than a 2+2. So my point is good show,keep up the good work,bravo
but dont dismiss something until it is accuratlly & catagorically recorded
as such. DJZ 60.:cool:
 
Throttle bodies,are still in the development stage
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Nope, been around a long time :confused:

Are Throttle bodies just being developed for the quarter mile or do
they have use elsewhere
Click to expand...
Nope been around a long time :confused:

Its about Thrust & velocity
Click to expand...
Only if you have a jet car (thrust is a product of a jet engine) -- remember secondary school physics "every action has an equal and opposite reaction"

Weight alone cannot be argument to fail,( i.e Bluebird) that weighed
more than a 2+2.
Click to expand...
Bluebird also had about 3000 horse power:confused:

Weight is a huge factor second only to power hence the term "power to weight ratio" the vehicle with the greater power to weight ratio, usually measured in Bhp/tonne (all else being equal) will nearly always win.

As I have mentioned before, the drag strip is one big laboratory and can be mathematically modelled with extream accuracy ----- claims of fast times can be somewhat verified purely on the maths, all you need is mass of vehicle (inc driver) elapsed time and or terminal speed and you can work out (within reason, say within 2 or 3%) the force or "power" required to do this, so if someone has for instance a 3000 lb car (+ driver weight) and claims to run say a 14 second 1/4 then they must have somewhere in the region of 240 rear wheel horsepower -- minimum. Its then up to you to decide if that is feasable or not:D
 
Nicely put Steve,
Why then, do we need identical engine componants/gear
in a match for match comparision in the Throttles v carb debate?
If, as stated, a result can be achieved by mathematical equation,
& aritmical competance,why go on the strip in the first place.
The anwser to all the questions & quest for figures can be derived
simply by calculating power to weight ratios.
Job done everybody's happy,present end figures (including estimated
cost's)& then whomever so desires can consider the upgrade.
I am not challenging You (Steve)at all . I think if people are given the
pros & cons of such a project then they will be convinced. DJZ 60.:rolleyes:
 
This has been a fascinating thread because it has shown up different peoples' preconceptions of what technology is all about, some fair and accurate and some wildly off the mark. Throttle bodies are not brand new black magic, they have been around for a long time as Steve says.

At the end of the day you pays your money and you takes your choice.

The idea of triples is very appealing if for example you want a period modification, whereas ITBs are a more modern, controllable and predictable take on the same theme..........however..... don't forget that FI was used on some of the works cars so it could even be argued that FI actually is a period modification in itself, the ITBs merely being a state of the art version of the original.

Whichever way you cut it, ITBs are a step forward in the evolution of tuning the L Series engine, they offer so much more in terms of flexibility and reprogramming that they make a great deal of sense. For example, if touring around Europe for 3 or 4000 miles it would be easy to load an "economy" map, if on a track day or drag strip it would be easy to load the appropriate map. Of course carbs can be reset and retuned but it would be more trouble and take longer.

Vive La Difference - there is room for every modification and idea no matter how controversial. Of course once the ITBs are setup beautifully, there is then the quest to shed weight......
 
Agreed Zhead !

DJ, still out there flying on the edge I see - nice comeback though !

Skiddy, I'm crap at maths so, given a 240Z weighing (with driver and enough fuel for the run 1200 kgs), with 225/50/15s, std 240Z gearbox and 3.9 LSD R200, what might I expect as a 1/4 mile time ? Do you need to throw into the equation factors such as a lightened flywheel, lightening reactions etc :) ? Oh yeah, power - let's say 270 bhp at the flywheel. 13.5 at the very quickest ?
 
ZHead your pretty much spot on there

DJZ
Why then, do we need identical engine components/gear
in a match for match comparison in the Throttles v carb debate?
Click to expand...

Because (as has been posted) its not just about a single brake horse power figure (that nearly everyone get fixated on :mad: ) its all about the delivery and characteristics of the engine, scientific testing methodology is all about measuring against a "control" and repeatability of the results, what we are trying to do, is make a direct comparison of carbs to ITB's in order to do this you have to rule out ALL other variables such as driver, traction, aerodynamics and engine components/mechanical differences. These comparisons have been done before by various scientists and motor racing teams and what really confuses me is why there is any debate at all, dont you think guys that if carbs performed better than ITB's then the motor racing world would be buying Webers, delloro's et al, like there was no tomorrow -- but no their not, in fact everywhere you look there are ITB' in fact its really only on period motorsport vehicles that carbs are mainly used.


Maybe we are all wrong, maybe carbs are the future and the entire motorsport world is wrong ----- NOT.

DJZ
The answer to all the questions & quest for figures can be derived
simply by calculating power to weight ratios
Click to expand...


Just working to a power/weight ratio will get you close but ideally you need the vehicles speed or elapsed time over a known distance this will factor in rolling resistance, power train loses and aerodynamics, if your not going to run it down the strip then how do you get these.
 
sean it is nice to note that in your opinion the engine that is sat in my car is not only not technologicaly up to the standard of steves engine but also is not capable of dropping into a road car and being used on the road. Maybe you could clarify those 2 points at some stage as I fail to understand why you think that. The engine has been developed as an engine that is capable of being driven through a wide rev range, just like a road car engine and deliver a useable powerband, just like a road car engine. By design and the use of technology it can also be run at continuous high revs, just like a race engine, and deliver a wide useable powerband, just like a good race engine. The car has been developed specifically as a hillclimb car. The sweeping statements that occasionally appear in your posts dismissing others ideas, projects or achievements do nothing to fight your corner for you. I appreciate that you are passionate about certain subjects and topics butmaybe sometimes it would pay you to sit back and take stock of what is happening or being said. The more this thread goes on the more it looks like a direct dig at skiddy and attempt to belittle or discount what he has achieved. 100 hp / ltr in a normally aspirated engine is a realistic top end figure to achieve from a well developed and tuned engine
 
ben240z said:
I have given you a direct comparison between an engine running on tripples and then the same engine running on injection, and before you say that it is a race engine so doesnt count, a race engine is only a road engine tuned. My engine could be dropped into a road car as is and be as drivable on the road as a standard 240z engine
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Sorry Ben,

I really have trouble accepting your last statement - if you say so, ok but allow me the grace to remain sceptical unless proven otherwise :) !

And your staement that a race engine is 'only' a tuned road engine - that is one understatement, can you compare a std 240Z engine and a road-sports 200 bhp engine ? Or are you saying that with your FI, your engine is as driveable ON THE ROAD as a std 240 engine ?

Does that really bother you that I believe that your engines' induction system is not at the same technological level as Steves ? You are getting excellent results and doing this your way, going down your own route ! That is something to be proud about ! I was referring to all the computer mapping that Skiddy does (and I suspect will increase as it apears to be very effective) - not block machining, lightweight materials etc !

I am not digging at Steve Kiddell and before you defend him, please ask him yourself if he feels that I am :).

ps I'm not digging at you either - life's too short friend !

Another sweeping statement : if Skiddy put his TBs on a bog standard 2.8, he'd get no more than 200bhp, same thing with triples. Add computer mapping and suddenly the TBs come to life giving 220 - the carbs need more engine mods to match this. The last 30 bhp that Steve has got has cost him the most ! The last 30 bhp from any engine will cost the most - it's logical and what I've been trying to say for yonks is that :

don't be misled by the association of 250 bhp and TBs, it's the driveability that counts - he can go higher but at what cost for road use !

Racings' gone for FI for perfect mixture and therefore economy, only trusted old methods use carbs - us dinosaurs.........
 
Is the argument about today’s car using FI a valid one, as there are only FI cars today!?

All cars in Europe/USA/Japan, etc have to run on FI to pass restrictive smog tests… Hence their racing version must run on the same set-up! The fact is that it’s not a limitation anymore… and being able to map it to your need is a MEGA +

But remember the 80’ most of the FI version of the era sports cars where loosing 20/30 hp… not gaining one pony! Until the boost in hp from the GTI, injection was an expensive device to pass smog test…

If you think that today’s carburettor are way behind in term of technology… just have a look at one of those 2 wheeled road rockets. Most of them are running on … carburettors! And they can make a lot of hp/ltr. True a lot are going to FI to pass the same restrictive law… And yes today there are not loosing power doing so! But they are more expensive!
 
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""100 hp / ltr in a normally aspirated engine is a realistic top end figure to achieve from a well developed and tuned engine"" - very doubtful from a two valve per cylinder, SOHC engine or if possible, undriveable on the road !

Ditto Boomer ! No smog :)
 
once again mon ami you are missing a massive point. The amount of computor mapping that steve is doing is part and parcel of the multi point injection route. What do you think took three days to complete on the dyno with my engine? He wasnt just running it in for me. There was a complete map to construct for the fueling, another map for the ignition. I will try to download a map from the ecu and put it on here and then you might just begin to understand what is going on with these engines. The only way to prove to you that this engine is as drivable as a standard 240 engine is for you to drive it!!!!!!!!!!!!!
 
We seem to have a re run of the V8 debarcle going on here - a focused attempt to show why this is the wrong way to go, yet diluted by quite some agreement along the way.

The whole point of sophisticated ECU mapping is that the power can be brought in from lower down the rev range to higher in the rev range with as much smoothness or "full on / full off" behaviour as the programmer and driver decide. The infinitessimal adjustment allows for driver style, engine behaviour etc etc to be taken into account for maximum benefit.

What started out as a good debate seems to have turned into a witch hunt somewhat, which is a little sad as these guys are pushing the envelope which will undoubtedly benefit the Z community in terms of knowledge and reference points for further developments.

These may be the state of the art today but they will undoubtedly fire imaginations and springboard ever more sophisticated developments tomorrow. I think it fair to say that both Steve and Ben's engine have a good chance of being surpassed in years to come but for now they are leading the way......way to go boys !

If there were more people trying to be creative and developing their cars the whole Z thing (particularly S30s) would stay vibrant for years to come. In my humble opinion this is a very good thing and something to be encouraged and applauded.
 
Zhead,

Name those who've turned this into a witch-hunt - it aint me, I want to discover all I can about TBs, I confess I'm learning all the way !

The whole Z thing (particularly S30s) WILL stay vibrant for years to come which is down to the exposition on many fronts, of the great diversity that our cars are capable of : road, rallye, circuit, drag-strip, hill-climb, hybridz and the undertaking of technological advances all in what is a car of more than 40 yars of age .......what have I forgotten ?

Ben - yes please :) and I hope this year I can return the favour ! Then you'll know how a real road car should behave - tongue in cheek friend :) !
 
I think that this thread is a revelation to those people (like me) who did not
(but now do) have an in depth awareness of what is involved in the TB
concept. I think also,that an ongoing,explanatary discussion brings out the
detail/info in a way that otherwise would be kept under closed doors.
I don't think anybody has been out of order,in fact questions have
been asked,returned & have been soaked in by the readers.
This is,what this club is about? being informative to those that are
not informed? My personal reason for asking the 'teacher'the Question is
purely for selfish reasons...I want to TB-map my transit van.
God Bless................DJZ 60.:cool:
 
Thanks DJ !

If I come across as hard - that's me, but this is an open discussion and the way to 'convert' people is to discuss openly and freely !

Stop being so sensitive guys, let's get on with the fight, sorry discussion :) !
 
SeanDezart said:
Zhead, Name those who've turned this into a witch-hunt - it aint me !
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Sorry if I got the wrong end of the stick Sean but it has felt a little like a digging exercise at times to undermine someone's effort and bravery in trying to go down a new path. Glad it was not and I misread it.

What have you forgotten ? Style, elegance, sexiness, pose factor - the S30 (my favourite) is a stunning looking car (again, just a personal and humble opinion)
 
I would like just to add that if anything good has come of this rather meandering thread at least people can see that

The drag strip is a useful credible diagnostic testing tool and a cheap dyno
ITB's are more than just EFI
Horsepower is more than just a number
The L6 is bl**dy hard work (and expensive) to get good power out of
Carbs are still retro cool with performance street cred.

And if anyone does turn up at the POD wanting to get an "idea" of Hp I will bring my laptop along (need it to tell the car what to do :( ) and will do the maths with you.

I also have another neat bit of telemetry (AP22 race technology accelerometer) that you can borrow, this is a great bit of kit -- accurately measuring acceleration and time against weight of car -- thus giving you real time performance figures of 0-60, 1/4 mile 0-100 etc and turning/cornering G's it will even give you fairly accurate rear wheel Hp figures based on the acceleration G's it measures, claimed accuracy to within a single percentage point
 
SKiddell said:
Carbs are still retro cool with performance street cred.
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yipee, gotcha!:D

I think any one that says Tb's are no good performance wise has to have their head tested to say the least!

My personal opinion is that I prefer the look of carbs with all its linkages and chrome filters etc, call it a little bling if you like but I feel it is more in keeping with a 70's car feel.As for knocking TB's, well only in jest as Skiddy well knows and anyone that thinks I would go ahead to head with him firstly to suffer a weight advantage and then poor fueling in comparison is simply mad.


OOPS, nearly forgot that obviously the reaction times would be much longer for Skiddy being that much older!:p


I will go and have a look to see if I can find a pic of typical fuel injection map for those that have never seen one, it's very interesting to see how it works!
 
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