power

[maxpaine]

yooooo
an 1.3 engine
whit forge pistons cam kit all the natural things
an weber 32/34 or 2 weber 40
whit racing exhaust manifold
how much power can i have in the engine?

[S_Gault]

how long is a piece of string.


sorry, to answer your question- power is a product of revs.

ive had over 130hp from 1300cc but you'll not do it on a road engine.

100bhp is about it for a road driveable one (no inflated dyno figures), anyone who says they have more are either lying or the dyno is miles out on calibration.

Steven

[maxpaine]

sorry but isnt only the rev
its a 1.3 rally

[dhdev (Oli)]

i had 102bhp out of my 1.3 (Head, cam, 32/34carb, 4into1 manifold). You can only fill the cylinders so much so revs are the answer, look at motorbike engines if you need proof of this.

[maxpaine]

thats why im going to put forge pistons

[m.d.]

motorbike engines are a very short stroke and have extreamly small pistons. there is no way that you would get a car engine to rev like that.

a friend of mine has spent 10,000 on an xe and it revs to 10 max.

[benji]

motorbike engines are a very short stroke and have extreamly small pistons. there is no way that you would get a car engine to rev like that.

v-tec? integra type-r's have 10k on the rev counter as standard

[Aragorn]

yer im sure the modern vtecs will rev to 9k fine

vaux lumps will have problems with lifters jacking up at that rpm so u may need to use solid lifters

might be worth looking into how the vtec lumps can rev to 9k without jacking up lifters

[m.d.]

sorry i meant to say a nova engine. lol you could allways whack a v tech in there :twisted:

[maxpaine]

i know tha a nova rally has a 9 rev od full

[BigRuss]

Posted: Sun Jun 27, 2004 12:57 am Post subject:

--------------------------------------------------------------------------------

i know tha a nova rally has a 9 rev od full




What :?: :roll: :?:

[benji]

how high does yours rev russ? could you go higher with throttle bodies instead of carbs?

[BigRuss]

My limiter is 8,250rpm, that is the highest that I've heard a 1600 8v Vauxhall engine being set at. And Yes I have hit it in fifth 8) I usually change up at about 8000.

I wouldn't gain any revs if I fitted Throttle bodies as the engine internals would still be the same, cam etc...

I wouldn't gain any maximum BHP worth talking about but would probably gain lower down the rev range with pick up. She'd pull better low down but that would be it. My car doesn't struggle low down anyway so I see no need to spend the money.

A friend of mine has a 1400 16v Nova which is on throttle bodies and revs to 9000 RPM. This however is not because it is on tb's at all, it is because it has Titanium rods, pukka pistons, titanium caps, solid lifters etc etc.... It would still rev to 9k on carburettors. It's for sale actually a snip at ?7450 complete :o

[benji]

what size chokes are you using in your carbs?? must be big if swapping to throttle bodies won't alter the top end.

[Stuart]

hes running 45'2 as far as im aware lol



oh russ, ill have 2 of those 1.4's ;) :D

[benji]

i thought he was running 45 carbs but what chokes?

ya think that 1400 will do a 15.9??? :twisted:

[BigRuss]

Didn't quite clarify that enough, ?7450 was for just the engine :o . It is 174bhp though.

Not 100% sure on choke sizes in My 45's, I'll try and have a look today and let You know later this evening.

[MC]

Two points:

TB's will not give you more low down torque. You may gain more torque, but it will be higher up the rev range.

100bhp on a road going 1300 is quite possible. What do you define as the point between road going and competition?

MC

[BigRuss]

That maybe true on a standardish/mildly tuned engine but not on mine. Remember I am running an MBE distributorless management system and My engine was mapped on a Dyno, Martin (Bowyer) has produced a few engines the same spec as mine on carbs and TB's. The only significant differences being that the TB'd jobbies produce slightly more torque between 3 + 4,000 rpm (Off cam so to speak).

Obviously if You bolt a set of tb's on to a std engine You would gain everywhere, but then again you would gain pretty much everywhere if You fitted a set of twin carb's.

And yes 100bhp 1300 is achievable relatively easily.

[MC]

I make that statement because I want to make it clear for people that have no experience of either.

If you have twin 40 webers with 30mm chokes, it will have a huge lump of torque from idle. You will not get that with 40mm TB's. As you say, you get a fair lump of torque at 3-4k, but to someone who is not a good driver and has no experience, they'll think that it feels flat low down and has porr driveability. The nature of the torque and power curves will depend largely on the diameter of the aperture and the length of the intake. The mapable ignition helps to iron out the smooth running isuues, and releases a few more hp.

Out of interest, does anybody know the restrictions/rules on a group A 1600 Nova engine?

MC

[benji]

the group a engine is in the build manual. it used 2.0 16 injectors, high compression forged pistons, a big cam, standard size valves but gasflowing is allowed. and a few other bits.


MC, i have 30mm chokes in my 1400 but below 3000rpm it is flat. and by that i mean if you open the throttle it just judders and if anything it slows down. i have a standard cam but will be getting a piper 285 soon. any idea's??

cheers

ben.

[maxpaine]

what is the engine are you all talking about ???

[benji]

http://www.novaload.net/features/viewfeature.php?ref=1095

[S_Gault]

benji- it sounds like you have it idling with the butterfly uncovering a progression hole, then when you open throttle, it goes lean.

very common, easy to sort.

Steven

[benji]

how do i fix it. it's on a set of dell'orto's

[MC]

That doesn't sound right at all, my 1400 used to pull like a train from idle and that was on 30mm chokes. As S_Gault says, you should be looking at what is wrong rather than more tuning.

How does the car idle? Does it splutter when you first pull away under light throttle? Who set the carbs up? Can you remind me what spec you are running?

MC

[benji]

velos set the carbs up but told me somting was wromg with them, they told me to look for a new set without saying exactly what was wrong.

i have a 1400nv bottom end a c14se head which has been matched to a 1300 manifold. it also has a 4-1 and system. i wan't to get the carbs sorted before i fit the cam because i will probably be re-building the engine at the same time so i want the carbs spot on.

i don't have a clue what jet sizes i am running, simply because i don't really know what i am looking for and i don't want to make them any worse. it drives great above 3000rpm but it is bad on idle and at low revs.

[Snowface]

when u've done a rebuild and got a new cam won't you need the carb's setting up again?

Sounds like its gonna be a quick 1400 N/a you're building.

[benji]

when u've done a rebuild and got a new cam won't you need the carb's setting up again?

yes but i want them working right before i start doing any thing else


Sounds like its gonna be a quick 1400 N/a you're building.

hopefully, although it will be miles behind the competiton. because the only other one will be CP's. :( i am aiming for 110bhp, shouldn't be too hard to get. i've got 92 now. add a cam and a decent bottom end and that should be over 100. then i will get some more head work done.(bigger valves, more gasflowing)

[S_Gault]

in realistic terms, I doubt youd make those numbers in a raod car.. not on my rollers anyhow.

if you want carbs sorted then pm me.

Steven

[benji]

why won't you get them figures?? CP and MC both had more than that from their 1400's.

you have pm

[MC]

S-Gault,

With the spec he is aiming for, what sort of wheel or flywheel bhp do you think is possible. I know its a broad question, but assume he is using 32mm chokes and revs to 7.5k (quite safe) with the following spec:

+1mm Overbore - CR 10.5:1
SE head (round port large valve) with enlarged valves and wasted stems.
Twin 40's with 32mm chokes on a carefully matched manifold.
BP285 piper or AST2 kent cam (timed correctly)
4branch and decent exhaust system.

I call that a moderately tuned road car, and I would be interested to hear your guestimates. I have seen different roads give different results for similar engines.

MC

[benji]

would you reccomend 32mm chokes for this set up instead of 30mm?

thats the spec i am aiming for.

[MC]

I couldn't say without trying both. I had a similar set-up without the overbore and used 30mm chokes. The engine was quite well balanced, but probably could have done with shifting the power band up a little.

MC