Mumbles
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| posted on 17/1/15 at 11:38 AM |
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How many is too many RPMs?
I'm considering some engine modifications and want to know how far I can go with the current bottom end I have.
Currently I have a black top 2.0 zetec with balanced crank, lightened flywheel, balanced rods and Pistons, race bearings big and little, 45 weber
carbs and a standard head with weber alpha engine management.
Currently limiter is set at 6,800.
I'm considering upgrading ECU to the latest alpha fully map able system and considering a new head and cams.
Questions:
How hard can the engine Rev with standard top end and current spec bottom end?
What would people's suggestions be regarding heads, cams, valves etc? And what other bits do I need to go with it?
Or for bigger rpm do I need to forge bottom end?
The car is only used on track but I don't want to run the engine on the ragged edge, it's only a track day toy so reliability is very
important.
Any thoughts/advice is greatly appreciated.
Matt
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ian locostzx9rc2
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| posted on 17/1/15 at 12:00 PM |
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Go to the burtonpower.com website lots good info on ford engines
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coozer
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| posted on 17/1/15 at 12:08 PM |
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ARP big end and rod bolts will help raise the rev limit. Balanced and matched crank rods and pistons will help as well.
1972 V8 Jago
1980 Z750
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Mumbles
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| posted on 17/1/15 at 12:24 PM |
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Forgot to mention I've got ARP bolts.
What would you say is a safe Rev limit in current form?
I'll have a look through burton to see what I can find. I need a clutch from them so might be tempted for a few other bits too
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Ugg10
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| posted on 17/1/15 at 12:34 PM |
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May need heavy duty valve springs, I know the zetec se needs them over about 7500rpm. Also may be worth investigating what cam you have as there is no
real benefit from reving the nuts off it when the max power point is only say 6500 rpm. On a standard cam I suspect just over 7000rpm is all you need.
---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com
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loggyboy
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| posted on 17/1/15 at 12:44 PM |
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Depends on where your peak power/torque is, and how your ratios dictate time in each gear. Pointless upping to 7.5 if peak power is between 5 and 7,
and between 3rd and 4th you onky use 1000revs.
Edit, should finish my reply quicker!
[Edited on 17-1-15 by loggyboy]
Mistral Motorsport
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Mumbles
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| posted on 17/1/15 at 12:57 PM |
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So with current bottom end my best plan is to upgrade head, cams and springs and increase limit to around 7,500 and this will all work well together
and not be too close to the edge?
Something like the 210/220 option from Raceline...
http://www.raceline.co.uk/products/part_section.asp?SectionID=53&CategoryID=4
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rusty nuts
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| posted on 17/1/15 at 12:57 PM |
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Is the new Alpha ecu user friendly or is dealer only mapping?
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snapper
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| posted on 17/1/15 at 01:02 PM |
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The rods tend to be the weak link, rod bolts let go
ARP bolts are the least you should do, balancing does not increase the Rev limit
I would also use ARP bolts for the flywheel and probably double dowel if 7500 is going to be visited frequently
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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Mumbles
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| posted on 17/1/15 at 01:10 PM |
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Rusty - yes the new alpha ECU is mappable by any rolling road or even yourself. If you have a current alpha they will take your old ECU as a trade
in.
Snapper - so only going forged will allow frequent use of 7,500? I'm guessing putting a fancy head and cams in is a little wasted without the
higher rpm?
So to sum up I need to save up some more if I want to upgrade the engine.
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johnemms
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| posted on 17/1/15 at 01:27 PM |
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Description
My standard 2.0 Blacktop - anything over 5230 rpm is not doing very much
 
Description
My max torque is at 4140 rpm
I could squeeze more out of it with fuel injection I suppose . 
Own chassis & Build - First time pass!!
"7's" aren't really "cars", they are 'experiences"
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coozer
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| posted on 17/1/15 at 02:06 PM |
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quote:
Originally posted by johnemms
Description
My standard 2.0 Blacktop - anything over 5230 rpm is not doing very much
Description
My max torque is at 4140 rpm
I could squeeze more out of it with fuel injection I suppose .
In hindsight, been there (carbs) done it (injection) and looking back wish I'd spent the money on head work and cams.
After I'd spent time and a lot of money on going to injection I was at a rolling day and a guy rocks up in an MNR like mine, 2l dunnel engine on
45,s... One power run later with 210bhp Mine made 178 and that was a st170 engine, his was a silvertip with ported head and cams..
DONT DO IT!!
1972 V8 Jago
1980 Z750
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Mumbles
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| posted on 17/1/15 at 02:12 PM |
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So stick with current Rev limit and do head and cams with no need to upgrade bottom end.
Thanks for everyone's advice and the £1,000 bill you've just convinced me of on head and cams!
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snapper
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| posted on 17/1/15 at 03:03 PM |
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You can go to 7500 with ARP bolts
The Black top 170bhp engine has forged rods silver top does not
Most cams even rally cams produce peak bhp around 6000 to 6500 only serious rally or race cams peak higher
For road use and some track you'll be fine but if you hold very high revs for a long time that's when problems start
Rods are limited by revs
Pistons limited by compression
Cams with more duration that produce peak power high up the Rev range need compression
So your then into the circle of bottom end rebuilds
I have run standard Pinto rods with just ARP bolts and 1 flywheel dowl to 7500
My other engine has Cosworth forged rods and will go to 8,000 the Pistons however are limited to 7900 and 10.5 to 1
The cam I like the most is the FR32, the FR33 may be a bit better but I do run an RL31 in one engine, it looses upto 3500 then flys
Horses for courses
I would recomend building an engine to your rods capabilities
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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Mumbles
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| posted on 17/1/15 at 03:19 PM |
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Thanks for the advice.
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whitestu
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| posted on 17/1/15 at 04:46 PM |
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Mine is a standard blacktop except for arp flywheel bolts and I have a limit of 7500. Nothing has broken yet, and I've gone over a couple of
times by mistake (8100 when the throttle stuck!).
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chillis
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| posted on 17/1/15 at 06:25 PM |
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A stock black top zetec with stock rod bolts and valve springs was rated at 6675rpm max intermittent and 6500rpm max continuous.
Note: not all black tops have forged rods, only the ST and Turbo have them - You have been warned!
[Edited on 17/1/15 by chillis]
Never under estimate the ingenuity of an idiot!
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snapper
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| posted on 18/1/15 at 09:26 AM |
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Some further research says 7000 on standard rid bolts
ARP bolts good for above 7500 some say 8k but I wouldnt
Yup I go for ARP rod and flywheel set limit to 7500
Dunnel and Scolar don't go much above 7400 soft cut and 7600 hard
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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matt5964
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| posted on 18/1/15 at 09:42 AM |
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quote:
Originally posted by snapper
Some further research says 7000 on standard rid bolts
ARP bolts good for above 7500 some say 8k but I wouldnt
Yup I go for ARP rod and flywheel set limit to 7500
Dunnel and Scolar don't go much above 7400 soft cut and 7600 hard
My engin was full done by Paul at dunnell and has a soft of 7400 and hard of 7600
We made 221.3bhp and 179ft/lb with Dave mapping it at emerald.
Runs perfect every time weather it be on road or track.
Luego velocity XT 2.0ltr 221.3bhp 178.9lbft
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Mumbles
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| posted on 18/1/15 at 10:26 AM |
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quote:
Originally posted by matt5964
quote:
Originally posted by snapper
Some further research says 7000 on standard rid bolts
ARP bolts good for above 7500 some say 8k but I wouldnt
Yup I go for ARP rod and flywheel set limit to 7500
Dunnel and Scolar don't go much above 7400 soft cut and 7600 hard
My engin was full done by Paul at dunnell and has a soft of 7400 and hard of 7600
We made 221.3bhp and 179ft/lb with Dave mapping it at emerald.
Runs perfect every time weather it be on road or track.
Matt, can I ask what spec your engine is?
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matt5964
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| posted on 18/1/15 at 02:50 PM |
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Created 2.0 blacktop
Jenvey throttle body's
440cc injectors
Lightened flywheel arp dowels
Arp head bolts
Arp rod bolts
Balanced crankshaft
Ported and flowed head inc manifolds
Custom dunnell cams
Competition valve springs
Raceline sump
Lightweight crank pulley
Comp ht leads
Full custom simpson ss exhaust
K6 ecu
Think that the lot
Luego velocity XT 2.0ltr 221.3bhp 178.9lbft
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