Mk1 race car (Ex slick 50) and Mk2 daily.

Sounds pretty lairy if the power band starts at 4800 - 300* or more I reckon. However, that's also a feature of KJet and lairy cams. When I went to Megasquirt the power band got wider at the top and bottom end - It ticks over like a little shopping car now - because of the greater flexibility in mapping the ignition curve. 'Only' a 285 cam though.

Are you allowed to change the management and stay in the current class?

As for the bottom end, I'd suggest you should pop the sump off and see what you've got in there. You might be able to spot fancy rods, forged pistons, modded crank...

 

Hi Mike.
thats it with the filter, no panel in there. Dont think they are available, although Chris said he had one that came with his slick 50 car...
I need to divert some more cool air onto it though, as it is drawing air from 360 at the moment.

I would have to up my weight limit to 950kg if I remember correctly - to make induction and injection 'free'. I may look into that, as there is no chance I can loose 60kg to get down to 850... Although 'car investment $$$$' has all gone! It may have to stay as it is this year.

I should take the sump off really, and check it out. I know the pistons are 'KS' from the spec sheet from 'Longman and Co', which I have read (on here) are fragile in the slick 50 engines I'm guessing there is nothing special in there unfortunately.
I know he used pugeot competition valve springs! Ha.

 

KS = http://www.kspg-ag.de/index.php?fid=1093&lang=3 I believe.

My old Slick50 engine was a lovely motor, revved beautifully, but did crack a piston in the next owners hands. I believe they were cast pistons, with the compression upped, hence the fragility.

Longman I'm sure you know!

The filter is a Jamex item, appears to have been a filter of choice for Slick 50 - or a coincidence that Sam's came with one too:

 

Kolbenschmidt are OE suppliers to VAG, BMW and many others, so I assume they're stock pistons running near the limits of the CR they can cope with. I think mine is a similar sort of build, but a 2.0 with a gentler cam. I've also heard people refer to 'Karl Schmidt' pistons, but I think this is probably a misunderstanding of what KS stands for, and they really mean Kolbenschmidt.

Is 850kg the car+driver weight?

No reason why you can't just enjoy the car as it is for the first season. Develop the handling, learn a bit more about the car, and about racing. Obviously you've got some expert backing to get you up the learning curve a bit quicker.

 

Cheers Chris, i never realised they were off the shelf items.

I remember seeing something similar on a 16v (sorry for swearing) once though cannot remember where, something to do with not having enough room for a standard box so was shortened but had same style boxing.

Can't you box the engine area off around the filter like they do with the cones on the turbo cars and have it right up to the outer edge of the radiator and just leave the front section of it open to get air into it all and also keep the hot engine air away from it (something i plan to try myself in the future), like this:



Also I asked about the other filter as i spotted it up there resting on the strut brace ^ ^

 

Normal K&N filter I think! At least it looks like the one I have in the Kitchen Parts Depot!

 

Aye thats what i thought, my old one got binned so needed to replace it so looking about before spending.

 

yeah, its the wasted K&N I took out, nothing left of it!

850 is with the car and driver, so pretty light with standard glass an panels - almost impossible to get down to???!!!!

Yeah this year will just be about getting the most out of myself and having fun. I plan to do a whole season and take it more seriously next year. I have some good technical support from my old man, but trauling this forum helps no-end! Particullarly as I wouldnt count myself as a mechanic.

The boxing of the airbox is something I plan to do I ran out of time for the first race.
But yeah, I'll just follow your yelow lines I reckon Should make a difference, as there is no radiator cowling...

I hope my pistons dont crack!

 

Looks like a decent car Sam with plenty of potential.

You should find the pistons fine at the current 11.25:1 c.r. The normal c.r on those spec engines are 11.75+ to suit the cam normally used...a Schrick 304... they 'would' break up the ring lands on the higher c.r over time so you should be ok where it is... I run customer road engines on 11.25 on std pistons without a problem.

However. .Yr not getting the best from the cam on the lower c.r, but the only solution is forged pistons and then you can run 12:1.

They will run about that power band you have on the std injection, with peak power around 7,200..you should be making 155-160 hp with that spec..poss the lower end with the c.r down in the safe zone. You would also pick up mid range power on a smaller bore exhaust system without loosing the top end.

You could bring power up to 175-177hp by ditching the k-jet injection and fitting a pair of 45 dcoe carbs. The low/midrange power would come up too..and drivability would be transformed. .tho I'd fit forged at pistons at the same time and get the c.r up.

After that, the current head can be re-worked for more flow / power, and then more c.r/better cam/steel rods if you wanted to go that far.

 

Great stuff, tell us how you get off with it all & what materials you use (fireproof etc).

 

Thanks for all that useful information MrHillClimber (Jason?). Valuable stuff. Hopefully I can give you some business in return I may need a few bits (baffles, gear linkage also looks interesting). You have PM.
Pretty happy its on the 'safe' side to be honest... thinking about it. I'm after some reliability while getting to grips with things - and budgets.
I am hoping to get a supersprint manifold at some stage, and a smaller exhaust if you reckon it could help....?

 

Cool, will do. I have made a few carbon/kevlar pieces recently (just experimenting) and fancied making it out of that. High temp epoxy etc. Not fire proof, but niether is the plastic airbox. Ha. I fancy a 4 litre extinguisher anyway really. 2.25 is tiny.
Brake ducting too hopefully. Give me a month or so though

 

No probs Sam... & you have a PM reply.

On that power level yes... I gained 5hp at peak going from a road spec Magnex system (2" bore?) to a 2.5 Supersprint system, but, lost 5hp mid range. I kept the bigger system as it's a high rpm engine and times on the hills were no slower, but it lost it's mid range punch on the bigger system.. you could feel it on the road, and the engine lost some of it's aggresive noise from the induction.

I have a customer 1800 8v hillclimb engine on 45 Jenvey's making over 190hp on a road spec Supersprint (with the small oval tailpipe), so big exhausts arnt always needed.

In fact I remember an ad/article way back in the early 90's when the 2.5 inch Jetex system came out and was fitted to Neil Beaney's (spelling Chris?) slick 50 front runner at the time (which I "think" Paul Rose bought?). It too gained a chunk of power at peak, but as the graph showed, it also lost a lot of low & mid range power... I'm sure I have it somewhere still, I'll try and dig it out and scan it in..it was in a Max Flower issue.. god knows why I remember that and not what I had for tea last night!

 

When my car came to me (ex Euro saloons/Welsh Sports cars MK1 racer) it had a std air box cleaned up in side, no filter and a 150mm dia pipe ducted from the front grill in to the left hand side of the air box (viewed from the front of the car). Gets plenty of cold air to the cylinders.

In addition it also had a 1600 gti metering head and 16v warm up regulator (with the back drilled to allow for mixture adjustment). It also ran a std twin headlight grill to fit the oil cooler, rad and air feed all in tidy. Seemed to work well enough when on track, rubbish off cam though or driving on the road.

Was claimed to be putting out 160bhp when I got it. I only tested it after adding twin 45's and mapped ignition a year or so later. It gave 160bhp then with the original Pack D head, Schrick etc, but the top end was a few seasons old at that point and it wasn't quite as crisp as it was when I had got it, but would have thought it was around 150bhp max on the std induction.

I think you might be better with a std air box modified with a big air duct as you then get a ram air effect at speed plus cool air at all times, must be worth 3>5bhp at speed over the filter you have on it. You could just box it in, which will help, but I still reckon the ram air effect must be an advantage. I have read tests that show motorbikes loose a lot of top end performance if you remove the ram pipes to their airboxes (they are designed with them).

If you change the exhaust manifold then make sure you match the gaskets to the holes in the head and the exhaust. When I first pulled mine apart, one was in the wrong way round and the other three were around 2>3mm smaller than the mainfold and head . How much power did that cost? Also get a good quality one or be prepared to spend a lot of time cutting welding and grinding to get it all to line up properly. In addition mine had a Longlife 2" S/S exhaust but the bends were not very clever, gained nearly 10bhp by changing it for an Ashley 2.25" rally system with proper mandrel bends, at the expense of a huge weight increase, had to go to steel solid mounts with copper sliders to keep it on the car!! Looked rubbish compared to the longlife system but looks are not everything.

The above is based on the assumption that you have to retain the original induction set up in the class you run. The internals are well documented here and in other threads. That's my little bit of advice anyway.

 

Thanks again,
All very useful stuff
Your gear linkage sounds great. Looking forward to trying it!
Sam

 

Thanks Tony,
I am considering putting the standard airbox back on, just to save the huge amount of work to box/seal around the 'open' one. Then I can just feed the front - as you say. Makes sense.
Looking at an ITG filter maybe.....


Yeah, I found a few differences in the exhaust gaskets from suppliers. Worth ordering a few types! I found the ones I already had where the largest and made no restriction on air flow at all. ECP and others where awful quality.

Thanks all, for your insight

 

Pretty sure if you get the OEM mk4 8v exhaust gasket it comes as one piece with the larger port size as standard. Makes it easier to port match the head and manifold.

 

On the subject of exhausts, the supersprint 60mm race items are very light compared to road systems, and you'd expect them to work properly too, given the manufacturer. They're not especially quiet though

I had one on the Mk2 2.0 16v golf I had. It would have struggled on some noise tests at 100dba or below, I reckon. About half the weight of a standard system though.

 

I'm not sure my 2.5 Supersprint is all that light... been a while since I fitted it though. It always passes the nose tests on the hills... I think it's normally low 90's... it's certainly not very loud... maybe the MK1 & MK2 systems are different Mike?

All the Supersprint exhaust seam the work well though.

 

^^ I guess they've made different models at different times. The one I had was made of thinner metal than the roadgoing Supersprints I've seen. Assume yours is Supersprint R series, Jase?