What rpm limit would you set

[Thumbs]

Looking for a bit of advice

I have a Caterham with the following build and am interested what RPM limit would be sensible if I am looking for good reliability balanced with reasonable performance. The car is used mainly for road but with the odd track day thrown in for fun.

1.9 Evo2 scholar block
Forged Pistons
Dual tang rods
Standard crank
Ported VVC head
Cams??? (I need to check)
Jenvey TB’s
Lightened flywheel
Apollo


Any thoughts

Thumbs

Edited by Thumbs on Saturday 7th November 06:44

[BertBert]

do you have a rr plot to see where the power and torque are? That'd help.

Just on reliability, I'd be no higher than 8k.

Bert

[Thumbs]

Unfortunately not, I am planning to get it on a RR but have not yet done so.

My thoughts at the moment is soft at 7500 and hard at 7750 but I was wondering am I being too conservative or even too aggressive.

Thumbs

[mickrick]

It's the standard crank that will kill it, especially if pistons and rods haven't been blueprinted, and the crank balanced with the flywheel and clutch.
I'd keep it conservative, and see where your curves are after the RR.

[Thumbs]

It has been balanced and was built DVA; at some point I will ask him what he recommends but as the former owner had it built I think it is cheeky to ask lots of questions given I have not paid him anything.

And just to note I am not after silly BHP I am looking for 200 ish

Thumbs

[Epimetheus]

Thumbs said:

It has been balanced and was built DVA; at some point I will ask him what he recommends but as the former owner had it built I think it is cheeky to ask lots of questions given I have not paid him anything.

I shouldn't worry about that . . . I have dealt with engine builders who have built engines in cars I have had and they have been happy to tell you stuff like that. They want people to be happy with their engines and any communication may lead to more work in the future. DVA will have all the info on the engine in his records and is better informed than anyone to recommend an appropriate rev limit.

[Red Seven]

Thumbs,
Drop DVA a line. I'm sure he will be more than happy to advise, regardless if he built the engine or not!
But if he did build the engine, then he's the best to advise!

[Mars]

Very much depends on cams but if you've either the 1227 or 1444 then you won't benefit from anything above 8000rpm. If it's been balanced then you **can** take it to 8000rpm so set the hard cut at 8K and the soft cut at 7800.

[Shaun_E]

My engine is very similar to that - I have single tang rods though, BP285H cams and it produces 226bhp. I used to run 7800 soft, 8000 hard but last year changed to 8000 soft and 8200 hard. The crank, flywheel and clutch were all balanced at Vibration Free.
Peak power is between 7800 and 8200 so there would be a benefit in running to 8500rpm but i would only do that if I had steel rods and would probably want a higher spec crankshaft as well.

[sfaulds]

I wouldn't be putting it under any significant load or RPM until it had been mapped.