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Time for tuning
So.. the bodykit is in place, the car is registered and road legal, so it's time to tune.
Don't want to cause hassle by fitting a DET engine (hassle at the MOT) so figured I'd see what we can do with the ET engine first. The goal is 200-250 bhp... so I would appreciate a dialouge about whether this is possible/viable.... and if not, what we might see for power from the following mods. Port the head. Hotter camshaft (is this necessary?) T25 Intercooler (probably volvo 740) cometic head gasket (or what do you reckon?) 0,9 - 1,2 bar boost.... Larger injectors and remap as required. I don't want to start making special exhaust manifolds and inlets, if it goes that far then I will fit a decent engine that is good for 300+ bhp. 200sx S13/14(?) gearbox and clutch already fitted... she spins 32kmh per 1000rpm... with 205/45-16 pirelli p-zero tyres... (192kmh **119mph** @ 6000rpm in 5th) I guess with the larger A032 205/50-16's she will have more top speed, just wondering if the S13/14 gearboxes have lower gearing.... Anyway.... open for discussion, tips and advice about the above tuning plan... Also interested in any ET tuning bits anyone might have knocking around.... Conkers.
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Website: http://www.racing-green.com Blog (with 180zx build pictures) http://racing-green.blogspot.com/ |
#2
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if your aim is a flywheel figure the ideas you have will get you there. You probably wont see more than 225bhp at the flywheel with an s13 t25 as a guideline.I would say that if your interested in fitting larger injectors then its probably worth you fitting a t28 turbo instead. You shouldnt need to fit a cometic gasket,Genuine Nissan ones do the job and as long as the car is setup right they shouldnt blow. A cometic one is nice for piece of mind or if you want to lower the cr, I guess you can decide on that once you have ported the head.
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#3
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the uk hotter cams, Piper and Autosprint, make the engine more lively at 5.5k on imho, certainly stops that 'hitting an acceleration wall' feeling where the cars acceleration feels to drop off even though it will happily rev out to 6,5-7 no problem. may be more noticeable in my car as it weighs almost half what an s12 does tho
S13/14 boxes are essentially the same externally bar the bell housings, but the internal ratios are different as is the oil system design. the uk and overseas boxes have different ratios so check what you have (also turbo and non turbo cars have different ratios, not all of which we get here). The best box is the later s14 box, s14a here in uk as this has a centre trap door system to stop oil surge. The s12/13/14 boxes are all from the same family and as they get newer they get fewer oil holes in the centre steel plate between the alloy bell and alloy tail sections. The oil tends to all run into the tail casing under hard accelertaion and starve the bearings gears synchros etc. the s14a trap door stops oil rushing to the tail housing but allows it to flow back under braking. im sure i have pics somwhere of the differences if you need them. Check which you have, you can always block off some of the oil ways with JB weld and make a trap door if its necessary for your usage. The s14 (uk) boxes are closer ratios, with a fair bit taller first, then slightly taller 2nd and 3rd. 4ths the same but 5th is shorter (giving marginally lower top speed). again check what the ratios are available where you are and work out which gearset suits your diff ratio/usage and tyre rolling radius. CNH
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Racing is life. Everything else, before and after, is just waiting. - Steve McQueen |
#4
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Yeah I think the cam is worth it, especially in conjunction with other mods, especially porting. CNHSS1 is right, these engines do drop off power at the top end, so its really just a case of trying to move the torque band higher. My max power was at 6.1k which meant revving it up to 6.5k essential. First of all I kept hitting the rev limiter by mistake as the power just didn't drop off at all, so it was a case of watching the revs to change gear before it cut in.
I managed to squeeze 240hp on standard management and injectors with a rising rate pressure regulator. For the sake of the intercooler, I used a volvo intercooler, but I would seriously try to get one of the jap style front mounts that can easily be bought off of ebay for £125.
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#5
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Pulled the head off the car tonight and the low compression on the tester after the sparkplug meltdown is a valve with a piece missing... ooops! and we were doing donuts in the parking lot before driving it in to pull the head off.... I'd say she was about 10 minutes from dropping the valve completely... I'll get pictures....
The pistons have 4 cutouts for valves... are all ca18et engines like this, or is it a det bottom end already perhaps.... ? I also noticed a piece missing off the top of one piston, detonation, only it doesn't look recent as I cant see any damage anywhere else.....but strange things are afoot (at the circle K) I think the muppet I bought the car off has already been in the engine rooting around... I mean, he was up for fitting a 200sx gearbox and clutch... and it looks like it has a T25 on it already now we can actually see it.... So I guess I am looking for a CA18ET engine... or may be willing to risk the grief from the mot guys by fitting a DET motor. If I go DET, what sort of power are they good for without getting into cams and silly money... are they really good for 300 at the flywheel just with some remapping, injectors and such? Or might just pull the bottom end apart and do it properly... get the head sorted and save the mot headaches.... I found a DET for sale for 300 quid and it's local to me here in sweden, but it has done 80 000miles... so not sure if it is worth buying an engine which is probably as bad as the one we are now pulling apart..... Come on.... give me some sound advice guys! Catch you later.. Conkers the pictures:
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Website: http://www.racing-green.com Blog (with 180zx build pictures) http://racing-green.blogspot.com/ Last edited by Conkers; 04-04-2007 at 00:22. |
#6
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That piston is fucked. Is it on no.4 cylinder? Defo from detonation probably where its been top speeded.
The cut outs in the pistons are correct. Its just that Nissan didnt make 2 sets of pistons for 1&4 and 2&3 so they made a universal piston with cutouts for any position. A DET is a much better breathing engine. It will see 300bhp at the flywheel on completely standard parts with exception of the turbo. You will hit a brick wall on the ET at around 230bhp, where after it will require some serious attention. This pic may sway you, its a comparison of DET inlet to ET inlet ports:
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