So, should I change my head?
 

Hi,

I'm afraid I'm one of those wierd blokes on here without a Nissan. I've got a Scimitar SS1 fitted with a CA18ET.

My current issue is that I've got a custom exhaust manifold, (allowing a top-mounted turbo) but that now the turbo fouls the distributor.

Right, so I figured that as the Bluebird has an end-mounted dizzy, I'd just swap to a bluebird dizzy right? Wrong, I've since learned that the camshaft is different at the back end, and I'd struggle to fit the dizzy to the Silvia head.

So maybe I swap to a Bluebird (Turbo) head, complete with camshaft and dizzy? Well, it's either that or chuck out the Nissan ECU and dizzy, and go for a MegaSquirt (or similar) aftermarket ECU and go distributor-less.

Any advice regarding the head swap would be appreciated, as well as any experience of MegaSquirt, or any other distributor free setups you guys might have on a CA18ET.

Cheers, Jamie :)

i had omex 500 series on my old s12, that was distibutor less, cnhss1 has an emerald ecu i think, get rid of that air flow meter as well.

changing the manifold design would be easier

got any pictures of how badly it fouls? must be an easier option to look at first

Guys,

Thanks for the replies, I'll get some pictures up tomorrow, but be assured the turbo fouls the dizzy location big time!

I appreciate the quickest way to get the car running would be to re-fit the original manifold (which I have). However, I would prefer the turbo above, for easier access, plus the custom manifold should be much more free flowing than the original. Oh, and I've got a T25 to go on in place of the T2, I'm prepared for a bit more lag for the extra top-end gains.

Time to read up some more on aftermarket ECUs methinks.

Cheers, Jamie

I seriously doubt the standard manifold is a restriction with a T25, maybe with a T28. I never found the T25 laggy at all, perfect on a ET in my opinion :) Dont think you'd see a good payoff for the work involved with a top mount on that turbo.

I'm going to be adapting an s13 bottom mount manifold for use with the t28 soon (if i ever get the flanges)

Ok, I do appreciate that I'd probably not get too many gains from the upmount turbo location, and that the work involved may seem too much for the benefits. However, I'm still at the stage of investigating all my options before I start work in this area, and if I'm going to do this project, I'd hate to finish and then 6 months later say "Ah crap, I wish I'd done it THAT way".

So how much benefit is there to an aftermarket ECU? Given the additional tuning options against the hassle and money involved? S13eater- you said you ran omex on an s12. Any advice on running these systems on the CA18ET?

Many thanks guys, Jamie

well tbh, its what ever you or your tuner prefers, unles you are mapping it yourself, i know from what i've been told that the dta software can crash a lot, i had no probs on the omex and it was on the same engine that you have, the ca18et, i ran the t34 and there was no probs with lag, although i had a well ported head by AMT engines and mapped by the same company, it came on boost about 3400rpm, although the sxoc crew say the afm is good for 270bhp, thats on a det engine which breathes better to start with, 54mm is a bit pathetic to say the least, you need at least a 2 3/4 inch exhaust, i used 3 inch, big turbo, better with the external wastegate, anything that makes the engine breath better is a must, the theory that because its forced induced, that you just run more boost and it will force the air through that it will be ok is bull,get the air flowing as good as you can, i've a few tricks on the fj which will help the flow and speed things up, but you will have to do some home work yourselves for that ;) .

Cheers S13eater.

I agree with the principle of reducing ANY restriction, I've always had the opinion of "look for the weakest link", hence wanting to keep the bigger manifold. I know the standard SS1 exhaust is better flowing than the Silvia, so I'm not looking to change that now, I will however install a new cold air intake.

http://i244.photobucket.com/albums/g...s/IMG_0048.jpg

http://i244.photobucket.com/albums/g...s/IMG_0049.jpg

This is the manifold as it is, you can see how the compressor will foul the dizzy.

Anyway, I need to swat up some more on my options for an aftermarket ECU, and see how much I can justify spending (and then spend double!).

tbh the flange wants to be centeral to equal up the runner lenghts matey:)

hmm, log manifold eh. I dont think you'd see any real benefits with that design to be honest, and as Shaun says you'd really want the turbo equidistant from the ports at least.

Regarding management, the standard AFM is good for 270 ish and its not to do with what engine its on. air flow is directly related to power, and the AFM measures hom much air goes in. You can however change things to run a bigger AFM. I will be using one from a Maxima/N60 eventually and re-mapping the standard ECU. standalone is all good, rom tuning is cheaper, so its the only option for me as I'm using the same kit to map my s13 too (323.7bhp at last RR visit)

http://www.nissansilvia.co.uk/vbb/sh...light=MANIFOLD

this would be a much better way to do it :)

Guys, sorry for the lack of reply so far!

Thanks for all input, you'll be pleased to hear I've actually listened to the advice...

I've decided to switch back to the original exhaust manifold, this is basically the same as a standard Silvia one, but it ports at the front of the manifold, not the back (otherwise the turbo would sit on the passenger's lap).

So far I've taken the uplift manifold off (b*stard of a job with only open-ended spanners fitting) and cleaned off all the faces. I checked Graham Walkers (Scimitar specialist) for gaskets - they wanted about 20 quid EACH, plus VAT and delivery! GULP. Thankfully my local Nissan dealer charges about a third of that.

Oh, and I've swapped the fuel rail and injectors for the standard units too. And yes, I did cover myself in petrol.

Right, onto my question:

I've found a round 2-pin (iirc) plug which I'm told fits the knock sensor, but what I THINK is the knock sensor is located just above the oil filter, and I don't see how the plug lead will reach. So is my loom following the wrong route, or have I got the knock sensor location wrong?

Cheers, Jamie

Hiya Jamie,
Yep, the detonation sensor is close to the oil filter. But sorry I can`t help with the lead.
Regards,
Ian.

there's a lead that plugs onto the det sensor, and a then into the plug on the injector loom

Rusty, Danny; thanks guys. :)

Ok, so I need another lead, that makes sense. I'll have a rummage through the car and see what I can find. Failing that I assume my friendly Nissan dealer would stock them - I want a new cambelt anyway. Er, and a water pipe banjo-bolt for the turbo, and probably some other stuff I've forgotten.

Oh yes, and I also need to find a turbo oil-feed hose, assuming I get a braided line made up, can anyone tell me the thread sizes I'd need?

Right, I think that's everything for now!

Cheers, Jamie

if you can't get a lead you can just bridge the 2 wires with a resistor. The sensor itself doesn't really do a lot and you shouldn't rely on it fo knock protection, but if you dont fool the ECU into thinking it's there the timing will be retarded 5 degrees (iirc) over 2k rpm so you'll lose power

Danny,

To be honest mate, if I can't find the lead anywhere it'll be a 5 minute job to lop off the round pin connector and wire up with some some spade connectors - thankfully the car is over a pit, so I can access the sensor easily from below. But I accept that it would run with just a resisitor too.

Cheers, Jamie

On what boost can run safetly the T25 on ou ET? Because i'll go to my third head skimmed and T2 at 0.8 bars, intercooled, cold spark, exhaust etc... Nerver hurt my car even on track session always troubles

i ran 16 to 18psi on the t25 , get it on the rollers and edge the boost up.