Craigorypeck
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| posted on 24/5/11 at 10:40 PM |
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Determining my redline
I reckon my engine is now broke in and FINALLY able to rev without pinking up to 6000rpm, but what max should I set my megajolt rev limiter??
If I supply the ingredients of the engine, anyone care to tally up what they think is safe..?
YB lump and head on bike carbs, balanced crank, newman fast roads, no solid tappets- still on hydraulic, Single opel VS30 valve springs, ARPs
throughout.
I think the steel innards could handle 9000? but the weak link are the tappets/springs?
Also does a T9 have a limit to the amount of revs put through it? Apparently a T5 can handle more BHP but no good for a screamer? Sneaky suspicion my
box is on its last legs at the min, fresh T9 or what?
Many Thanks 
[Edited on 24/5/11 by Craigorypeck]
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coyoteboy
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| posted on 24/5/11 at 11:12 PM |
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Revs usually stress the rods, main and big-end bearings and valve springs first, springs are not such an issue - you just get valve float. If the rods
haven't been uprated and have not been proved elsewhere to be good at higher revs I'd not be raising the limit over stock personally?
Sorry, I've no experience with the specific engine.
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snapper
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| posted on 25/5/11 at 06:53 AM |
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The rods are good to 8,500, what piston have you fitted, if Cosworth or forged then 9,000 if cast just under 8000.
Fast road cam will probable peak much earlier therefore no reason to rev much past peak power, what your set up will give you is a missed gear safety
margin.
Hydraulic litters and single springs will limit your usable revs.
If your Type 9 is on it's last legs a proper rebuild with better bearings or fit the Cosworth T5, much stinger than Type9 and MT75 and has much
better ratios
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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atspeed racing
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| posted on 25/5/11 at 07:26 AM |
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Rev it till it goes bang....then its less a few hundred!!
As already said, the lifters are your limit.
Where is peak power? no point in reving beyond peak power really
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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mcerd1
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| posted on 25/5/11 at 07:40 AM |
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if I remember right the des hammill book rates single valve springs to 8000 (not sure how much the hydraulic lifters will limit that)
the cossie bottom end should easily be as strong as that with forged pistons
but the powerband on the newmans cam is quoted as ending ~7000, so personaly I'd set it between 7000 and 7500 to play it safe or nearer 8000 if
you have to have a bit more and accept the risk
gearbox wise you've got a few options - the T5 is a good option and probably the storngest
but BGH do some uprated type 9's with ratio's of you choice that should be plenty strong enough for an NA cossie
there HD boxes have stronger bearings and oiling mods that the say are plenty for 9000rpm or more 
(I've got an BGH 'E8' for mine)
(I'm going to try for a limit of 7000-7500 if I can convince myself the head will take it on my pinto with its cossie bottom end )
]
[Edited on 25/5/2011 by mcerd1]
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40inches
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| posted on 25/5/11 at 08:10 AM |
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As said above, rolling road it, find peak power revs and you have found your rev limit.
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JimSpencer
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| posted on 25/5/11 at 08:16 AM |
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The 'No need to rev past peak power' comments are a bit unusual?
It really depends where the power comes in, and the rev drop through the gears.
If you've got a cammy twin cam that has power coming in at say 6k, with a 2.5k rev drop, even if peak power is only at 8k you'll be
wanting to rev through to 8.5 so you're in the power band when you change up - yes
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mcerd1
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| posted on 25/5/11 at 04:03 PM |
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^^^I'd agree with that (as long as the head is strong enough)
also thats the way most tin-tops I've driven are geared, the red line is a bit passed peak power / the end of the power band, but if you change
up just before the limit your revs will stay in the power band
of course if you have a nice close ratio box you should hardly have to leave the power band at all....
[Edited on 25/5/2011 by mcerd1]
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Craigorypeck
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| posted on 25/5/11 at 09:32 PM |
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Thanks peeps! I have accralite forged pistons in it, bottom end will out rev the head no probs I think so with a rolling road session soon I'll
get a good compromise between the head components and power graph.
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