Cams 'on the cheap'

7th November 2016, 12:24

So, i'm a firm believer in not really throwing money at bigger power till you've mastered getting the best from what you've got already - but now that i've got my lap times consistently hovering around the 63/64 second mark for Knockhill - i'm starting to think about where I can get a bit more power to help me out with straight line speed.

I'm going to be getting a bit more serious in terms of the weight loss over the winter in the hope that'll help be go quicker as it stands, but I think I could still do with a little bit more help up that hill!!

I'd previously written off the idea of cams on the basis of the fact that to do it 'properly' with new lifters and mapping etc to suit, its going to be knocking on the door of a grand, for what will be fairly minimal gain in the scheme of things. Its just never seemed like particularly good bang for your buck to me. I guess there always comes a point though where it gets to that stage where nothing comes cheap.

However, i'm now starting to wonder if theres any merit in doing cams 'on the cheap' for want of a better phrase and using them without the additional costs of mapping and / or on the existing lifters.......

What can I expect from running a car unmapped on, for arguments sake, a set of 743 Catcams?

What are the reasons 'not' to go down this route? I can accept a crappy idle - but i'm not wanting to shorten the life of the engine or put it at risk.

Car is solely for track use, and is standard engine wise apart from exhaust and enclosed air filter.

Any input welcomed and appreciated

7th November 2016, 14:47

what mods do you have now?
cos if its lap times you want then c/r gear kit +/or LSD will make 3-4secs minimum a lap --that is far more than bit more power will do

there is no set of ratios from ANY std citroen /pug that are anything like correct for a race track +knock hill I know very well having won may titles there a few years ago

7th November 2016, 15:45

Thanks for the reply John - appreciate the input.

3-4 seconds a lap is massive round knockhill - that would see me lapping around the minute mark. Maybe something I need to consider as well then.

Like I say, fairly standard power wise other than basic breathing mods. Hi-spec 4 pots and bigger master cylinder, bilstein suspension (unsure what the springs are - bought second hand), Peugeot sport torsion bar and some sticky ar-1 tyres.

8th November 2016, 08:26

your std gearing with equate to 140+ at rev limter in 5th --you will never see anything like that --so lowering overall gearing by 20% will drop rev limter in fifth to about 125mph --and you still won,t have the BHp to get that on knockhill
touring cars with 300+bhp only gear for 130+ for knockhill

8th November 2016, 08:56

As it stands i'm probably running about 80% of the lap in 3rd gear.

I'll briefly make 4th on the back straight before dropping to 2nd for the hairpin, and i'll see 4th again just after the start box before dropping to third for duffus and staying there all the way through to the back straight again.

Like you say, i'm not seeing anywhere near 125mph - i'd suggest current max speed is probably somewhere around 100mph give or take.

Dare say it would mean totally re learning the track again, but maybe there's merit in that.

Down side again is cost - in my head theres gotta be at least a couple of grand in a CR kit and a diff...... am I in the right ballpark?

8th November 2016, 09:58

Quote:

Originally Posted by ESD1711

As it stands i'm probably running about 80% of the lap in 3rd gear.

I'll briefly make 4th on the back straight before dropping to 2nd for the hairpin, and i'll see 4th again just after the start box before dropping to third for duffus and staying there all the way through to the back straight again.

Like you say, i'm not seeing anywhere near 125mph - i'd suggest current max speed is probably somewhere around 100mph give or take.

Dare say it would mean totally re learning the track again, but maybe there's merit in that.

Down side again is cost - in my head theres gotta be at least a couple of grand in a CR kit and a diff...... am I in the right ballpark?

Thats a fair assumption. You will have to decide the balance between lapping faster and enjoying yourself at the level the car is at.

8th November 2016, 10:01

Quote:

Originally Posted by ESD1711

As it stands i'm probably running about 80% of the lap in 3rd gear.

I'll briefly make 4th on the back straight before dropping to 2nd for the hairpin, and i'll see 4th again just after the start box before dropping to third for duffus and staying there all the way through to the back straight again.

Like you say, i'm not seeing anywhere near 125mph - i'd suggest current max speed is probably somewhere around 100mph give or take.

Dare say it would mean totally re learning the track again, but maybe there's merit in that.

Down side again is cost - in my head theres gotta be at least a couple of grand in a CR kit and a diff...... am I in the right ballpark?

less than 2 k for gear kit-- probably about 1800-inc vat--the effect of lowering gearing by 20% is 20% more power at wheels --under 3k with lsd --which you really need to get best --then think about more power
bottom line is you will get better lap time by spending it on g/box than 3k on engine alone --cos it will end up with narrower power band that wants to rev higher --which will make ratios even worse--at moment you will have a power band from 3800-to 6800 -
you could just go for a dif =lower final drive to start with which would help --then you are spending about 1k that if money is tight is probably best option

8th November 2016, 11:07

Thanks guys - must admit this is something I've not even given much thought thus far to be honest. My knowledge of gearing and ratio figures etc is as good as zero.

Having just taken a look at the options available it looks like theres two options on the Quaiffe kit - a Close Ratio one and a Group N one. What are the differences in those? (yes, different ratios is the answer here, but I ask as someone with little knowledge of what the numbers actually mean or equate to) I assume it would be the Close Ratio set i'd be looking in to?

Harking back to my original question (appreciate that this has perhaps been a far more interesting discussion than that one might have been anyway!) - is it safe to assume that chucking £300 at a set of cams and running them as the car stands wouldn't be wise or beneficial then?

9th November 2016, 11:19

If it is cams that will run with std ecu and not wild ones then ou can expect 15bhp -20bhp ,and that will not make the same difference to lap times as lowering overal gear ratios =lsd --will it be a backward step -
-no --but maybe later you will want to go t/bodies etc --so then that would be a different spec of cams --.
for me --i would always get handling +braking +gearing right first in the list of things to spend on

you can have another engine you can build at your leisure as money allows -- cos next step will be stand alone ecu anyway for serious engine mods -and you still have the option to go n/a or turbo or my choice s/c ,you will need ecu which ever way you go --
watch out for my car it is now in the hands of someone up there s/c 6 speed squential +all the goodies close to 300 @wheels

9th November 2016, 12:24

Thanks John, i'm totally with you on the handling and braking being the priority, that's essentially what I've been aiming for this year.

Ultimately, s/c is the dream. It was through my friendship with Tam which I learnt of GMC in the first place - have always said that if money ever allowed, your number would be top of the list of folk I'd want to call.

10th November 2016, 20:44

Reducing weight is priority number one until it gets too expensive. Dragging weight up the hill out of Taylor's is almost painful.
13" wheels is gong to be the cheapest way to lower the gearing and there's a ton of cheap slicks available from single seater front wheels.
You can get 280mm brakes inside 13" wheels if the design is right and you have proper calipers.
Cams won't gain much laptime without a map because the 'area under the curve through the rpm band your gear ratios force you to use' may end up being less than stock due to a loss of lower end power and the stock, ECU imposed, rev limit of 7200/7300 rpm; so you lose bottom and and can't access the top end.
The stock single plug ECU is fine up to 8128 rpm so fine for quite an aggressive engine tune. Beyond that the rev limiter is disabled so you'd probably want to fit an additional one if you were wanting to rev it beyond that.
Three plug can be used up to about 20k....

11th November 2016, 08:31

Sticking the thing on a diet is defo top of the priority list over winter now. Fibreglass bonnet, tailgate and polycarb windows getting purchased. Pondering over complete doors given the weight savings possible, but not sure i'd fancy a side impact with just fibreglass doors - cage only has single door bars as i'd originally planned to use the thing on the road - if I were buying my cage now, i'd have gone for the double diagonal door bars for sure.

13's would mean a change of brakes as they wouldn't fit over the hi-specs.

Inevitably, theres going to come a point where its going to need some kinda 'tuning' for sure though.

I swore when I started this it would remain 'fun' and that I wouldn't go chasing lap times in it.......... shoulda known better really!!

11th November 2016, 08:34

yes we had big brakes on our ax race car --but wheels to fit had to be multi piece ones to get clearance using std 283mm citreon brake parts
-- think special calipers and discs will work out more expensive than a pair of rims--
yes you could go 13 ",still going to need an LSD --so why not lower final drive at same time --
always lots of ways --the choice is yours

11th November 2016, 23:56

Quote:

Originally Posted by ESD1711

13's would mean a change of brakes as they wouldn't fit over the hi-specs.

That's a good enough excuse to get rid of them because they are pretty shit calipers.

AP, Alcon and most Brembo are good calipers, every other one I've used have been flexy garbage that open up when you put pressure on them.
Too many people replace perfectly adequate sliding calipers for crap four-pots.

12th November 2016, 12:13

Without trying to insult you, is it only the car that needs to go on a diet? There used to be a mate of a lad up the road from us who spent thousands on lightening his Toyota Starlet Turbo, yet he weighed over 18 stone & couldn't understand why a lot lower power cars left him for dead. Have you seen the size of F1 drivers these days, really surprised there are not more women in the field.

12th November 2016, 21:10

Quote:

Originally Posted by Phaeton

Without trying to insult you, is it only the car that needs to go on a diet? There used to be a mate of a lad up the road from us who spent thousands on lightening his Toyota Starlet Turbo, yet he weighed over 18 stone & couldn't understand why a lot lower power cars left him for dead. Have you seen the size of F1 drivers these days, really surprised there are not more women in the field.

I figured putting the money saved by not buying cakes could be put towards magnesium and titanium parts.

However, it's not good when you can see your teeth through your cheeks. :-)