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Old 9th March 2005, 11:33   #1
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Question carb or mpfi? which gives more power?

well since we do have a lot of tuners in this forum...i thought that this would be a good thread to discuss the various pros and cons of the carb and mpfi, also who prefers which?
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Old 9th March 2005, 12:17   #2
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well iceman91, why dont u start off by mentioning your own experiences about carb & mpfi's? i would like to know the differences as i feel you have a very good knowledge of both.
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Old 9th March 2005, 12:55   #3
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I don't know much details, and don't have practical knowledge. All I have with myself is theoritical knowledge. Based on that I'd say the mpfi is more powerful. But it all depends on how the ECU is programmed also.
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Old 9th March 2005, 13:22   #4
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Well, you can't make a blanket statement by saying MPFI produces moe power than a carb!

However, going solely by stock street cars, it is clear that the switch to MPFi produced a jump in power. Take the Esteem which went from a 62hp carb to a 85hp MPFI. Thats 20hp more by simply changing the way fuel is delivered to the engine. That gian is almost universal on all vehicles.

Tuning-wise also it would be a lot easier to work with MPFI than it would a carb, provided you have the correct equipment. Ofcourse thats the key point - correct equipment, and thats where carbs score over MPFI's. it's easier for the layman to work on a carb engine with basic tools. You need to be a software engineer to do any work on MPFI's!
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Old 9th March 2005, 13:34   #5
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with mpfi and 4valves/cylinder ,the m800 changed from 37bhp to 45bhp ,the zen from 50 bhp to 59bhp and the esteem from 65bhp to 85bhp.
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Old 9th March 2005, 13:44   #6
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well i have seen a couple of funny cars in the drag races (think thatz what they are called) running i think 1000 bhp engines with carbs. have seen advertisements for quite a few monster carbs on summit racing catalogs too.

i believe its basically upto the tuner. if its something like a DIY sort of stuff then the carb should be fine. by the way didnt we see the PUG hit quite a few rides at the bangalore speed run?

depends on the config one runs. but i think for the same engine under identical condtions the mpfi should give more power.

was that right???

Last edited by Harrie : 9th March 2005 at 13:47.
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Old 9th March 2005, 15:49   #7
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Quote:
Originally Posted by speedsatya
with mpfi and 4valves/cylinder ,the m800 changed from 37bhp to 45bhp ,the zen from 50 bhp to 59bhp and the esteem from 65bhp to 85bhp.
Well that's company tuned cars set up for just the right amount of power and Fuel Economy... Having an mpfi setup hasl allowed them to tune even further (like having a tuner under your hood who keeps resetting the fuel curves for your driving style). Another thing please realise there have been major upgrades to the engine to get them to be MPFI ready hence it would be wrong to compare them directly.

As for this topic for company produced car's yes MPFI's are definitely better both in terms of FE and Power.

But when it comes to performance tuning Carbs can be as good as mpfi systems and way cheaper(Please Note:"WAY CHEAPER"). However there is one point for which you need a master tuner for your carb setups... MPFI tends to give you a wide torquey powerband and carb setups have a narrow powerband (but this again varies on the type of carb setup used: a single throttle body carb gives a very narrow powerband, but multi throttle body carbs allow you to have varied venturies and individual jetting to manage the powerband.)
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Old 9th March 2005, 17:07   #8
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well guys...
a carb and mpfi can both achieve same kind of power. it all depends on the engine and tuning. the jumps in maruti were prominent beacuse of totally new engine designs not ONLY due to mpfi changeover.
for example the earlier honda engines from the civic which we have today in india were much more powerful and they were carb. the 1.3 civic was 90bhp same which we have in the ohc 1.3.
the issue of carb and mpfi comes in when.:
STOCK CAR
for this an mpfi unit is much better in todays times because it is easy to maintain and the power/fe is pretty good.
PERFORMANCE CAR
this is where the tuner and the required tools come into play. a tuner might prefer an mpfi or carb depending on the mods to the car.
also since we do not have a lot of equipment required to tune cars running mpfi to our requirements, carbs are preferred. they do not require a dyno,laptop, tuning software and the required experience/knowledge. also these things are way too expensive for us. thats why most of the tuners opt for carbs as they can be sourced easily and setting it up is easier.
mpfi whereas is a nightmare (trust me i know, first hand experience) to tune it you need a lot of patience and money. firstly you gotta source the right parts whih will cost you quite a bit and then teh tuning starts where you practically need a garage close to your atm. MOST important of all you need adyno or at least a lapyop with wideband afr as well as a good engine management.
after all this if the tuning is alright you have a dreamcar in your hands. the advantage is once you have got the hand of the electronics in your car it ias very very easy to do further mods.
so to sum it all up
stock car= mpfi= hassle free/good power/mileage
performance car= carb easy to tune...very cheap
performance car= mpfi tough to tune very very expensive but if done then it is awesome
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Old 9th March 2005, 17:46   #9
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Well laid out Iceman. Mpfi tuning can be very frustrating, expensive, turns your brain into mush etc etc. But at the end of the day when everything falls into place - very sweet.

Wide band afr is only the begining, EGT, fuel pressure , injector sizing etc etc. Sourcing parts is not difficult - thanx to the www, but unlike abroad where you can walk into a performance store and pick and choose the stuff you require, in India it is impossible.

Mpfi is a totally new concept and there arent too many people who you can go to for any advice. Therefore expect to blow a couple of engines before you can get things spot on. Mpfi is here to stay, and if we are looking for performance it's time to hit the books once again.

Cheers,

Sideways.
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Old 9th March 2005, 17:53   #10
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yeah sideways tell me about have learnt it the hard way...

Last edited by iceman91 : 9th March 2005 at 17:54.
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Old 9th March 2005, 18:25   #11
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Hey Ice man,

Why dont you get all the guys together and make a trip to chennai this weekend ? Theres an event at the track here for Mpfi esteems. 4 sprint races. Each race has nine laps. 2 drivers per car. 1 Compulsory driver change per race. Shud be a lot of fun.
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Old 10th March 2005, 09:57   #12
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would love to but none of us have an mpfi esteem.
is there any way we can hire one of the prepared cars?
yeah even dom and tazim were interested
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Old 10th March 2005, 15:07   #13
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Quote:
Originally Posted by iceman91
would love to but none of us have an mpfi esteem.
is there any way we can hire one of the prepared cars?
yeah even dom and tazim were interested

Iceman,

We have 3 cars but all are taken. I had told Dom about the event about 2 weeks bac but he did not reconfirm. Any way why dont you guys come down for the weekend and watch the races.

Cheers
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Old 10th March 2005, 15:27   #14
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ok. done will speakt to dom and call you.+
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Old 10th March 2005, 15:31   #15
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Hey sideways, isn't this a 3 hour endurance race? what's this about 9 lap sprint races?
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