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Old 5th April 2007, 00:51   #76
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I'll be coming over with Rs 7 tomorrow.
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Old 5th April 2007, 00:53   #77
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I'll be coming over with Rs 7 tomorrow.
Me too .. Me too .. Ritesh arent you joining us too ??
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Old 5th April 2007, 01:02   #78
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Originally Posted by mclaren1885 View Post
I guess its the ratio of the rod length to that of the stroke ..
rod length and stroke are same ..

I think what rocam was saying..
engine was designed for a rpm and corresponding to that rpm the rod length/stroke was selected, the length of the stroke from TDC to BDC determiones the crank angle which makes the best pressure for the best explosion. so if we are running very high rpm the original stroke may not be suitable for this range..
e.g shorter rods may be at diff angle to the crank pin as compared to a long rod for a power stroke. (a)so the angle determines how much torque it can supply to the pin, (b)also the length determines how much time the piston is going to be near to the TDC or BDC affecting how hard it sucks in air or how hasrd it pushes it out
so if we are going for very high ranges we may be just making noise and not much power
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Old 5th April 2007, 01:35   #79
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Originally Posted by mclaren1885 View Post
I guess its the ratio of the rod length to that of the stroke ..
yes you are right rahul but i will try to explain what exactly is that

The Rod to stroke ratio has direct relation with piston speed & torque curve it produces take an eg of Honda 1.5Vtec it has bore of 75mm & stoke of 84.5mm i dont know how much exactly is the rod lenght but compare it to rod length with stroke of motor it has a lower Rod/Stroke ratio this combination produces very good torque at low & mid rpm range cause the angle at which the piston exerts pressure on crank is more but as rpm goes higher & higher the torque curve starts falling cause piston speed has increased tremendously & intake manifold,cyl head is not able to cope up with air flow demand also with higher piston speed it becomes difficult to get perfect ignition timing by the time it ignites & pressure is created at higher rpm the piston already passes the peak cyl pressure angle and going down.
where as in higher rod/stroke ratio eg 84.5mm bore & 75mm stroke the stroke is less but compared to rod lenth it has higher rod to stroke ratio the angle at which pistons exerts pressure on crank is less hence it has rev happy nature since angle is less the dwell time i.e the time piston travels BTDC TDC & ATDC is slow compared to the above hence controlling ignition timing is much more easier this combination has low low end torque but has torque at higher rpm & can carry it to redline.

as a rule of thumb lower rod to stroke ratio produces better low to mid range torque & higher rod to stroke ratio can carry torque to the redline.
hope it explains.
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Old 5th April 2007, 01:43   #80
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Originally Posted by chetanhanda View Post
if u are not staying with NA engine
going crazy extreme with cams,turbos ,ITB's and NOS you cannot use saturated type they have a max capacity they can supply fuel upto..
tuboing it to extreme will need more fuel and bigger injectors and then the "peak and hold" come into the picture...if we want to go all out crazy

so definately type of injectors have a relation with NA or turbo application.. if this is the context u were referrng to ..
There are plenty of high HP engines running saturated injectors, they have a rating like 650cc,750cc,1000cc injectors depending upon the application.
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Old 5th April 2007, 01:47   #81
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Originally Posted by mclaren1885 View Post
Me too .. Me too .. Ritesh arent you joining us too ??
Hehe...I have a standalone so I wouldnt need this one. My RD0601 Race ecm gives me the flexibility to set my revv limitter wherever I require precisely and a lot more without any hazzles!!!

Mcl/V1p3r: Take your 7 bucks and stock ecm, knock RDKarthiks door...you wont be disappointed I reckon.

Lets stick to the topic guys...

Last edited by The Wolf : 5th April 2007 at 01:48.
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Old 5th April 2007, 02:06   #82
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Quote:


Originally Posted by mclaren1885 (FAQ for tuning fuel injected cars - Step by step virtual buildup!)
I guess its the ratio of the rod length to that of the stroke ..

Originally Posted by chetanhanda
rod length and stroke are same ..




No they are not, read post # 79

Last edited by Ford Rocam : 5th April 2007 at 02:12.
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Old 5th April 2007, 02:31   #83
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Quote:
Originally Posted by Ford Rocam View Post
Quote:


Originally Posted by mclaren1885 (FAQ for tuning fuel injected cars - Step by step virtual buildup!)
I guess its the ratio of the rod length to that of the stroke ..

Originally Posted by chetanhanda
rod length and stroke are same ..

No they are not, read post # 79
ok.
read post #72 by Wolf, im saying the same what wolf is..
its bore x stroke .. instead of rod x stroke which relate to the same.

Rod/Stroke Ratio is a different thing
isnt my post #78 and ur post #79 explaining the same thing in diff words..

Last edited by chetanhanda : 5th April 2007 at 02:35.
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Old 5th April 2007, 02:45   #84
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Well, this link should help explain rod to stroke ratio...

Rod Ratio Effects - Page 1

p.s: pardon me for my ignorance on post num 72

Last edited by The Wolf : 5th April 2007 at 02:48.
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Old 5th April 2007, 06:47   #85
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Originally Posted by Ford Rocam View Post
There are plenty of high HP engines running saturated injectors, they have a rating like 650cc,750cc,1000cc injectors depending upon the application.
ok.. then peak hold can go upto even 1600 cc capacity..more than saturated type..
1] saturated type are used due to cost constraints and simplicity in being compatible with stock circuitry , for hi peformance the "peak and hold" are better..
2] saturated injectors are slower than "peak hold" type nearly 1- 2 ms faster..and also they are more accurate and mantain continuity from cycle to cycle..

why dont you compare the internal workings of both and see which is better ? there wont be many reasons supporting saturated for hi end applications..

also for eg.. companies saying peak and hold is better are MSD ignition ,RC enginering and AEM , AEM even came up with a special 10 channel injector driver for eliminating slow saturated injectors..
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Old 5th April 2007, 08:33   #86
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Originally Posted by The Wolf View Post

Mcl/V1p3r: Take your 7 bucks and stock ecm, knock RDKarthiks door...you wont be disappointed I reckon.

Lets stick to the topic guys...
That info was for you. I think its inappropriate to put it up on the forum.

We do not offer them as a service/product either. We have however built them for various benchmark testing.

Let us pls not deviate from topic.

Last edited by rdkarthik : 5th April 2007 at 08:49.
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Old 5th April 2007, 08:50   #87
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Originally Posted by rdkarthik View Post
That info was for you, not for the forum.

We do not offer them as a service/product either. We have however built them for various benchmark testing.

Let us pls not deviate from topic.
Ritesh , you are in trouble for leaking out classified info it seems ..

Jitu , so according to my understanding if your rod length increases then theoretically the rod ratio too increases which amounts to an engine revving faster .. So say , a replacement rod is about 2mm longer than the OE one .. What would this amount to in terms of performance ?? Also what are the advantages or disadvantages of oversquare blocks then in terms of rod ratio ??
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Old 5th April 2007, 09:03   #88
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Quote:
Originally Posted by chetanhanda View Post
2] saturated injectors are slower than "peak hold" type nearly 1- 2 ms faster..and also they are more accurate and mantain continuity from cycle to cycle..
It has been widely acknowledged that peak and hold are better.. Inj open times on saturated can be less than 1ms at optimal voltage.
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Old 5th April 2007, 09:35   #89
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Arent high impedance injectors also called as saturated type and low impedance as peak and hold type ??
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Old 5th April 2007, 09:49   #90
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WOW! this thread has really become 5 star
Very very informative indeed.

so as for as my understanding goes:
1. We can either use stand alone ECU (which will replace the OEM ECU) or use a piggy back ECU (stand alone seems to be better because you will get PC software with it and better flexibility)
2. We can modify the fuel maps on laptop and then download to ECU
3. We can use dataloging with PC software to see the effect of changes in the fuel maps and make changes accordingly
4. Need to use wide band AFR and EGT sensors/gauges to get correct mixture
5. I think all these will be open loop systems, can we have a close loop system with any standalone ECU?

please tell me everyone if I am going in correct direction?
sorry guys if I am quoting very basic things here trying to learn form all of you

Quote:
Originally Posted by mclaren1885 View Post
So say , a replacement rod is about 2mm longer than the OE one .. What would this amount to in terms of performance ?? Also what are the advantages or disadvantages of oversquare blocks then in terms of rod ratio ??
can we replace a con roads? wont it increase the compression ratios of the cylinders?
as far as my understanding goes, crank diameter = stroke length
increase in con road length will just push the entire stroke towards the cylinder head,
yah, it will decrease the angle at which con road pushes the crank, this will improve the abality of con road to carry more power/load at higher rpm
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