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SR20DET in a 240Z, problems????


Guest Anonymous

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Sspikey, you and I are on the same page. My SR20 was bone stock internally, no cams, cam pulley, no head work, nothing. I didn't even have external mods either (besides the turbo system and MSD 6AL).

I solely used Jim Wolf to provide me the ECU, 50lb. injector program using the Ford Cobra air mass sensor. He now has a 72lb program available with the Z32 MAF sensor. Some like his tuning, others do not. I find it safe, although not tuned for peak performance, it does provide you with a rather safe 12:1 air/fuel ratio. You can speak to Clark at JWT to discuss your specific needs.

 

I figure a 2200lb. vehicle with 400WHP on a stock engine should be able to hit low 11's to high 10's if I hit a good '60 time. More importantly when I road race the 240Z, I can brake deeper going into the turns!

 

I have a SBC engine in my garage right now, and have amassed a bunch of parts to install it. My dilemna is that my heart belongs to the high revving SR20 but my wallet belongs to the V8.

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Guest sspikey

high reving hells no STAY BEHIND the 7500 rpm redline on stock head shit breaks realllllll fast after that on stock head i know :) My philosophy on the motor is that nissan's top engineer designed the block, the summer intern did the head :).

 

Jimmy hat's tuning is trash. 5 cars i had running his garbage and his ditributor setup (mind you back in the day he suckered us into buying that trash) anyways NONE ever idled, None ever ran right and always puffed smoke. One was so rich it would burn our eyes at idle. Mind you he said all was fine and we should go get the car tuned. GO GET THE CAR TUNED??? i thought thats why we paid you. So we all took the decision this year to go to oem ecu, DIS and rom chips and dear g-d what a difference. cars idle, are faster, smoother, no bucking at mid-high rpm and are ultimately PERFECT so i will never buy jwt shit again. even his clutch sucks

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This was my point to begin with. JWT's ECU programming is always on the safe side. I haven't had any problems with his programs. Sometimes it can be other things that people blame the ECU for. I am not saying that JWT is a tuning god or anything, but I know of several SE-R's and 240SX's that are running low 12's to mid 11's with his conservative tuning. I am not familiar with his 280ZX programs, but sometimes it can be user error or other times you two didn't discuss clearly what you need for your particular application. I've had two back to back ECU's from JWT, one NA and the other was the turbo program. Both idled like stock, wasn't pig rich, with excellent throtttle response. Maybe the programmer was smoking dope when he was burning your ROM chip.

 

As far as the stock head not revving past 7500rpm, I'm sorry but you are wrong on that one. My program for the turbo ECU had the rev limiter set at 8000rpm! I even had a shift light with a 8K pill to verify it. I've never broke any valvetrain parts. I have heard it could happen if you hit the stock redline repeatedly and you'll experience a piston to valve slap thus destroying the engine entirely.

 

JWT is not the end all be all of NISSAN tuning, but he is a safe bet. My goal is to either run a HALTECH or AUTRONIC system so I can have my own parameters set and not some average for all cars as JWT does. Again, it's a easy plug and play solution, but not the cats ass for all out HP.

Take it for what its worth.

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Guest sspikey

we got 7700 rpm cutoffs with our jwt ecus and chose to stay behind the 7500 rpm redline. Other motors we have tried to get higher on stock head has yielded nothing but broken rockers arms and miscellaneous crap which 500rpm is just not worth the hassle.

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Every bit of rpm is beneficial when properly mated to the correct sized turbo!! The SR20 can also benefit from the Greddy rocker arm guides to prevent valve float and rocker arms flying every where. I am just trying to get you to seperate personal feelings from fact. There is one insane MOFO I know of who has a stand alone ECU and is consistently shifting at over 9K on a "stock" head!

PM me for more details.

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Guest sspikey

I gotta say ive never heard of 9 K on stock head but that is sick give him big thumbs up for me.

We do run RAS they are always the first things to be installed and have saved our asses a few times when miss shifting.

 

I think i will be going SR powered this summer in a 240Z tired of 240sx need something cool again and my car = played out :P

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  • 2 weeks later...
Guest tkrskyline

Yeah, our engine has a slight tilt to it, but not as much as it looks. It was our first and would just have required a little more custom work to make it flatter which we would probably do next time although there has been no adverse affects with it this way. The engine physically fits very well and mounts arent too hard to make. We are doing one now in my miata and thats going to be much harder with a custom oil pan, custom mounting for the miata power plant frame( a ladder bar that connects the tranny to diff), and very custom mounts along with other stuff. We are also just finishing up the two Z32s. I will post about them when they are finished. One should be done today.

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  • 3 weeks later...
Guest AREITU

About halfway down the third page, the posts stop making sense, in a literal sense, not a logical sense. Just a bunch of stuff that I can't follow.

 

Anyway, after watching Best Motoring Volume 5, the one with the inline-six challenge, there was an R32 Skyline GTS. It had an RB20DE with individual throttle bodies and was stroked probably to 2.4 liters with an RB26 crank. It sounded very very mean.

So if you're thinking about staying with six cylinders, don't mind being a little down on power while saving a few bucks, you could put in a naturally aspirated RB20 or 25 and adapt ITBs to it. Knowing how many people would rather just cough up a few more bucks for a more powerful motor, it's not gonna be a common swap anytime soon. :)

 

Lemme know what you guys think.

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There's no doubt the the SR20's weakness is in the rocker design. It really was a cheap way to finish an otherwise fine engine....

 

Other factors that may influence the SR vs CA arguement:

SR uses a single row timing chain, the CA uses a belt.

The SR is an all alloy block, and is not very easy to overbore (sleeves generally used).

Fitting larger injectors to an SR ususally involves the requirement of a GReddy (or equiv) rail & manifold.

The late-S14 SR's have VVC.

 

Some pros, some cons, nothing too serious. And you all k now how heavy an S13 is compared ot a S30.

I could just keep up with a S13 Silvia K's with my stock L28ET powered 4-door Skyline, so try trimming about 200kg off the weight & you're close to the mark.

 

I know how hard the 'top model' SR20DET goes - my sister owns an N14 GTi-R (SR20DET AWD, 180+kW stock)

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  • 2 months later...
Guest cs14silvia

well I just got this 1979 s30 280z and thinking of doing a RB25 conversion. I have this cs14 silvia k's ( T28 ball bearing) The modes I have on the cs14 is very basic, turbo acturator, exhuast , intake no ecu mod, no front mount intercooler. well the dyno sheet indicates the car had 193kw at rear wheels. stock internal, good stuff. I changed the head to s13 sr20, cos they dont have variable valve timing(hence good for high boost)

 

anyway for my 280z, i am thinking of doing a RB25. not becoz its got 2 more cylinders but coz RB is heavier(in fact 80kg heavier) I was aiming for good drivability, ad I saw this big L28 engine then think maybe its a good idea to put a rb25 in there( but I donno if this 280z got 50:50 weight distribution) I always thought in america, sr engines are not many, since some of you have done this conversion, please tell me hows the weight distribution ?

 

In NZ , we have plenty of sr20s or rb25,26, even RB30DET (my friend got one in his 180sx) SR20s are cheaper than RB25s. Maybe i should get a SR :)

 

another thing is I am wondering what is the weight distribution for RB25 in a 280z? how is the handling compare to SR20s?

 

Please advise any info as I am about to start my 280z project.

 

zfever, just wondering whys a R33 in da foto? :-D

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  • 5 months later...

About that weight distribution thing. . . I haven't actually weighed a SR powered 240Z, nor have a corner balanced it, but I'm guessing that it'll actually be pretty rear heavy (especially w/ a roll cage). Which leads me to believe that the car will need to be set up more like a mid engine car(like the MR2) for it to handle properly. By this, I mean changing the spring rates accordingly, along w/ more rear biased braking to compensate for throwing off the balance (need for larger vented rear disks).

 

This greater weight bias towards the rear may make this car oversteer more, but IF setup correctly, SHOULD improve lap times considerably (look at the high level of braking performance of rear biased cars like porsche etc.)

 

One thing that would be really nice, though is that you could fortify the front end w/ chromoly piping throughout the engine compartment. The Zs, especially the older ones, have a very weak frame (especially the connection b/w the firewall), and could use major stiffening up front.

 

I'm planning on starting on my SR swap sometime around January (when I get the donor), so I'd like to get some reference on the weight distribution. Can someone who's done this swap post their weight distribution as a reference? I don't think I'm the only one, but I'm sure I'd appreciate it. Realistically, my Z probably will be in the shop for a year or so since customers' cars take priority, but we'll see. :(

 

Kenny

http://www.rbmotoring.com

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Having access to the corner weights on a 260Z SR20 conversion the numbers were:

 

48F and 52R with an overall weight of 2165 lbs.

 

That's a car with no interior, aluminum dash, R180 diff, fiberglass hood, Autopower roll bar, rear mounted battery, and custom mounts so the engine was further back and lower then most SR conversions.

 

The weight distribution numbers and total weight were exactly the same as my L6 powered 240Z. Why? Well, my L6 was moved back 6" and down 4" in the chassis and I was running a few carbon fiber panels.

 

Chassis setup was not much different then in a normal 240Z. The weight distribution difference from stock 52/48 is not great enough to require wholesale changes to the suspension.

 

Remember, 911 and 993 Porsches run a 38 to 40 F and 62 to 60 R weight distribution.

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:D Thanks johnc!!! That was exactly the info that I was looking for. I'm actually supprised w/ the distribution, though. I thought that it'd be less weight in the front (hence my reference to the porsche).

 

I forgot that the L series motor is lighter than the RB series motors. Probably a lot, too w/ it's smaller head and lack of turbos etc etc, but I'm very supprised that the difference is that minor. I know the weight difference of the bare block b/w the RB and the SR is about 80lbs., and I firured once you factor in everything, the weight difference would be pretty staggering (especially the tranny, but that really doesn't affect the weight distribution).

 

I'm also planning on doing the R200 and multilink swap also, so for me, at least, I think the rear will weigh more that yours. But the numbers you gave me will be a good reference in directing what I'll be doing w/ my future project.

 

BTW, as reference, does anyone know the weight dist. of a factory 240Z?

 

Thanks,

 

Kenny

http://www.rbmotoring.com

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Stock weight distribution for a 240Z is 51 or 52F and 49 or 48R depending on the year and the options. I've heard a lot of numbers thrown around regarding engine weights but a modifed normally aspirated L6 is not that much heavier then a turbo SR20 when you add in the weight of the turbo, intercooler, plumbing, etc.

 

I know that my L6, with all the work that was done to it by Sunbelt, weighed in at 505 lbs. (certified) while in a box and bolted to a pallet with the following stuff also in the box:

 

Intake manifold

Header and Y pipe

Computer

Engine wiring harness

Alternator

Clutch

Flex plate

Starter

Coil packs

Plug wires

Engine mounts

Cold air intake

Air filter

 

Comparing stock for stock and you do see a bigger difference in engine weights between a L6 and an SR20DET. But how many people bolt in a stock SR20DET and how many people are driving around with stock L6s?

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  • 3 months later...

JohnC,

I've seen your 240z on other sites, very impressive indeed. Especially your lap times. I'm curious about suspension setup though. You said the difference between 52/48 stock and 48/52 weight distribution wasn't much. Did you have to make any adjustments in your setup? Also, the sr20det with turbo/manifolds/stock IC/accessories and tranny is ~490 lbs, and your L-series engine fully assembled in crate was ~500 lbs, so with tranny that would be a bit heavier (~75 lbs) than the SR swap, right? Or did that 500 include the tranny?

Thanks

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My 505 weight above included everything in the list plus the weight of the pallet and crate. I would guess 550 lbs for my particular engine and the Quaife 5 speed sequential transmission I ran.

 

Regarding setup, I did change the front/rear roll stiffness based on the wieght distribution changes fromt he car's original configuration. I ran a 23mm front and a 19mm rear anti roll bar instead of a 25mm front and 19mm rear.

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