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Lotus in the Peak
28th - 30th June 2024

Sabre Heads Kr1 Plus Newman Phase 2 Cams


Phil S1

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Ooh Stripey back on the road in three weeks! Exciting!

 

Dean, only if things go to plan :) Anyway Phil, i would not like to commit on the amount of lift you can safely dial on. An email to Roger or DVA should produce the required information. The primary and secondary exhaust manifold lengths are vital apparently. A pic of a Jim Valentine K series special for comparison.

 

P1010001-23_zps0bd03c03.jpg

 

As you can also see i asked Jim for the flexy in the SCRP. Im hoping this will help with the noise police.

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Other big difference to my KR1 is I run a match bore plastic intake not the alloy one. I suspect this could be the clincher as the alloy doesn't seem to work so well on lower spec engines ie below 170.

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I know the alloy plenum could be part of this. I fitted it because I prefer the look of it but realise it could well be worse than a de-flashed plastic one, so I may yet go back to it. It would save quite a bit of weight too!

My throttle body is an alloy one but it is still just 48mm and with a wedge. It does look like there could be something to be gained in de-wedging it.

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  • 3 weeks later...

Thought I'd update you on where I am with this currently....

My plan was to reconvene with Brian to check the timing, check the cat hadn't collapsed and look at improving the induction side of things before another trip to the rolling road, that plan has gone slightly awry at the moment. As yet I haven't seen Brian or checked the cat but instead concentrated on the intake. I didn't want to fit a Hurricane or the like as I ran something similar some years ago and found it too noisy for my liking so I opted to fit a K&N panel filter and modify the airbox to accept a larger intake hose from the side vent. I also decided to have a go at de-wedging a 48mm throttle body.

So I picked up a virtually new TB and modified it as per the seloc TechWiki:- http://wiki.seloc.org/a/Throttle_body

Here's a couple of photos of the modified one against my std one:-

IMG_8559_zpsca1e4f11.jpg

 

IMG_8562_zpsf58c466f.jpg

 

As well as removing the wedge you can see in the photo above that there's also a lip near the butterfly that I've also removed on both sides to smooth the airflow.

 

I removed the old airbox and intake hose, you can see from this photo the somewhat tortuous route that the air has to flow round before it even reaches the filter:-

IMG_8565_zps4fd2127a.jpg

 

I picked up another airbox and decided to try and fit a 100mm dia intake hose into it, the reason being that 100mm fits nicely over the elliptical intake vent on the clam. I also managed to find a very reasonably priced 100mm dia elbow normally used in ventilation ducting for cooker hoods and shower extractors and the like:-

IMG_8568_zps1eec383d.jpg

 

and then the final piece of my jigsaw was the K&N filter:-

IMG_8569_zps53f9da58.jpg

 

The airbox isn't quite wide enough to accept a 100mm dia elbow but I found by cutting a slightly elliptical hole I was able to deform the elbow sufficiently to get it in, here's the hole:-

IMG_8571_zps42932c9d.jpg

and here's the elbow fitted, following a quick flash over with some satin black paint:-

IMG_8581_zps981e9ad1.jpg

 

IMG_8582_zpse0221900.jpg

 

Two things to note here, I had to fit the elbow angled downwards as shown above in order to clear the pipes to the charcoal canister (shown in the next photo) and I needed to fit a rivet to hold the elbow in place whilst the Tiger Seal dried. Once the Tiger seal had dried I also ran some silicon sealer round to seal any other little gaps.

 

There's a couple more photos to come and the conclusion to this particular instalment but I think I must have reached some kind of upload limit as I can't upload any more images....so you'll have to wait for now ;-)

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post-4822-0-41207300-1371503577_thumb.jpgI have a very similar mod. Its easier and better if you relocate the canister to the clamshell effectively sitting on top of the rear most part of the sill the pipes and cables reach fine then the hose reaches fine mine is 100mm also. Oh it sounds great imo
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Thanks for the replies, good idea to relocate the charcoal canister Legin and as you say the cars sounds so much better now!

As regards the price, a Hurricane kit looks to be about £170. If you're willing to modify your existing airbox then the cost of mine adds up as follows:-

Half metre length of 102mm dia 2 ply black neoprene ducting - £14.99 plus £1.95 postage.

100mm 90 degree elbow joint - £1.49 plus £1.99 postage.

K&N filter - £27.99 inc postage.

Grand total - £48.41

 

So, to complete yesterdays instalment.....

Here's a photo of the modified airbox installed and showing how the angle duct avoids the pipes to the canister:-

IMG_8585_zpsfc0889f4.jpg

 

And then one more with the neoprene intake hose tie-wrapped in place. (I had to cut about 5 inches off the overall length):-

IMG_8586_zps0e9c1326.jpg

Not quite as direct as Legin's would be with the canister relocated but nonetheless there is direct line of sight from the car's side vent into the 90 degree elbow so still miles better than previously.

So, another job done and time to fire up and try it out. I did the TPS reset procedure and had to get the idle adjustment set again and then I was ready to go.

The car felt instantly better than previously, probably more than any other mod I've done, I presume this was down to modifying the throttle body....and the increased induction sound was lovely without being too excessive. However..........I have another problem!

After I had the basic KR1 porting done, and prior to fitting the camshafts, once or twice I had an occurrence where after brisk acceleration beyond say 6000rpm the engine started misfiring. It would just about tickover but wouldn't accelerate cleanly until over around 3000rpm. If I stopped, switched the ignition off for a few seconds and then re-started, all would be fine again. I spoke to Rog about this at the time and it is something he had known occur, specifically on S1's it seems. He feared it could be a fault in the ECU but also suggested swapping the TPS sensor, I had a spare so I tried that and it seemed to fix it.

Now, with the addition of cams and these mods I've just done, it will start misfiring every single time I use more than around 5500rpm. Keep the revs down and all is well. So the car's still fine for driving on the road but I think trackdays are out of the equation until I get it resolved.

I did a bit of research in the seloc archives and found a few similarly modded cars that encountered very similar problems and one in particular by Greg_S which was pretty much exactly my spec of car with identical symptoms:-

http://forums.seloc.org/viewthread.php?tid=311487&page=1#pid5291153

If you read through it you'll see he changed just about everything without success until he had an Emerald fitted.

I can only assume that the ECU just can't cope with the amount of air now coming in. There's also a theory that the MAP sensor being located within the ECU on an S1 might be a contributing factor in all this? I am going to try swapping the TB back to a std 48mm one and see if that minimises the problem again but as Greg_S found, I am starting to think that I'm going to need an Emerald to fully resolve it and get the best out of all the mods. It still could be that my ECU is faulty, I could potentially pick up a secondhand one but from what I understand it is not just a plug and play swapover but requires a tool to synchronise with the alarm immobiliser. So that option could cost me maybe £150? and may be no better than I am now so it's not an option I'll be taking. I'd sooner put the money towards an Emerald I reckon, in the knowledge that will fix it once and for all.

So close....I can feel all the right elements are there...I just need something to make them all talk to one another wink.png

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Well if you're stumped Martin then I'm really in trouble laugh.png

I ran it today with the std 48mm TB back in, it did seem to lessen the misfire but not eliminate it altogether. It felt less lively too so I'll definitely be putting the de-wedged one back on again.

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