So, should I change my head?

[Jamie Hicks]

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

[s13eater]

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.

[PukkaSilvia]

changing the manifold design would be easier

[sideways danny]

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

[Jamie Hicks]

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

[sideways danny]

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)

[Jamie Hicks]

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

[s13eater]

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 .

[Jamie Hicks]

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.





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!).

[s13eater]

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