ATTN: L28T & Those Considering SDS (long)

[Scottie-GNZ]

Anyone looking to build a quick L28T-powered Z-car should read this.

 

A couple of months ago I posted some pics of my buddy's 71 with an L28T. Here is one of the pics I posted.

 

 

Here is a little background on the car. It originally had a stock NA block, P90 head, Jim Wolf setup, t3/t04 hybrid, 440cc injs, Spearco I/C, stock DP and 2.5" press-bent exhaust, open 3.54 and 225/50 tires. The car ran a best 12.32 @ 114.5 running 22psi and detonated its way down the track. We decided to do some upgrades along the same path I took, so he installed an SDS "F" system, 600cc injs (run at 36# FP), one of my DPs and a 3" mandrel-bent exhaust with an Ultra-flow and a LSD.

 

Couple of test runs and the junkyard NA block decided to pack it in by cracking the rings on 2 cylinders. Eventual effects of over 100 passes Since the motor was broke, we decided to run it anyway expecting it to hand-grenade and instead was rewarded with a 12.7 @ 113+ with 17psi boost and a soft launch. Daniel (74_5.0L_Z) was there to witness that as this car and his look identical, both drop-dead georgous.

 

He got a junkyard turbo block and freshened it up with new rings and bearings (note I did not say pistons!!). For personal reasons, he decided to sell the car but had to see what it could do. Last Wednesday night on the first real test of the new setup, the car ran a best of 11.74 @ 119.9mph with 19psi boost on PUMP GAS and 225/50 radials!!!!. The car was a little "sluggish" in the 1/8-mile with only 92+mph, but it gained over 27mph in the 2nd half. To top things off, he got to break out a can of "WHUP-ASS" on a brand-new Z06, 3 times On the quickest run, the Z06 ran 12.4 @ 112+, pulled the Z off the line bad only to have the Z walk on him on the top-end. Man, am I proud of that car.

 

Lets talk numbers. With the JWT setup, my formula spits out 304RWHP. With the latest setup, 350RWHP. Thats a 45hp increase from the SDS, good exhaust and bigger injectors (probably not that big a factor). Remember, FIRST TIME OUT, LESS BOOST, PUMP GAS, STOCK ENGINE!! Now, for those looking for this kind of performance, am I advocating not spending the big bucks for forged pistons? Absolutely not. My point is that you can go a VERY LONG way with the stock turbo engine if you can keep the heat down and eliminate detonation. Some folks would look at that little turbo and laugh, but what counts is the right combination of parts.

 

Programmable engine management, Fuel system that can deliver, non-restrictive exhaust system and last but not least, a top-notch I/C.

 

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Scottie

71 240GN-Z

http://www.mindspring.com/~vscott911/gnz.html

[Drax240z]

Hehehehehehehehe. *cackle* *falls off his chair*

 

First, that is an awesome engine bay, obviously a lot of work went into having a show quality engine and engine bay, and it looks SWEET. Second, I guess this shows pretty well the differenced between a T3 powered car (scotties) and the upgrde to the t3/t04. Scottie didn't you run 13.09 with the T3? Thats a gain of 1.35 seconds just based on upgrading the turbo. (of course, some other things ARE different, but its not a bad guideline)

 

This car is a good example of the path I've been hoping to follow from the start. Stock bottom end, good fuel and ignition control, and slowly bolt on upgrades until I am up there around 300rwhp. Do you have an estimate how much money went into this car? (I've noticed he's not gone cheap on some things, spearco intercooler = $$$$, looks like an HKS BOV there = $$$$)

 

Thanks alot for posting this.

 

 

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"Gimme Fuel,

Gimme Fire,

Gimme that which I desire"

-Metallica

 

Drax240z

1972 240z - L28TURBO transplant on the way!

http://members.xoom.com/r_lewis/datsun.html

http://members.home.net/drax77/newpage.html

[Guest Anonymous]

After many late nights laying in bed with insomnia thinking about what to put in the 240, I decided to go l6 turbo. Vastly faster and easier to get running, and much less expensive things I need to buy. Plus a 240 turbo is what I've always wanted, a v8 never really wet my whistle(Oooohhhh that sounds dirty!) because I'm just not a fan of huge engines, and I'm a devout turbo addict.

I found an 80k mile spotlessly clean l28t locally for $550 + $100 core. I'm thinking if I flash a crisp $500 bill in front of him he'll take it.

I had originally planned on rebuilding a p90 head and putting it on my non turbo l28 with NisMo flat top pistons. With a 2mm head gasket I figure that's around 8.5:1 or so compression ratio. Figure buying the $600ish engine will save me from buying a $200 head gasket and save me lots of other work(adding oil lines to/from turbo, etc, etc, etc) and it's worth the money. Plus I can keep my NisMo everything engine together and hopefully get more money for it than I could for just the head and carbs alone. Add in Sunbelt wanting $300-500 to rebuild my p90 head I got, and the junkyard l28t engine sounds much nicer.

Opinions on which would be better in the long run? Either way I've always been planning on using sds. The junkyard engine is lacking the distributor and turbo. Don't need dist, and have always planned for a big turbo from the start - not worth trying to get every last horsepower from a wheezing turbo in my opinion.

I'm leaning towards the junkyard turbo engine. I could slap it in the car in a coupla hours, slap turbo on, and hopefully the sds won't take more than a day or two to get installed and running(opinions on that scottie?). So it's much, much faster, which is good for me.

Fill me in, 'cause unless something else crosses my mind I'm probably gonna pick up that l28t and put it in over x-mas holiday. I have a spare t25(ack) that I can use until I get the big turbo in, and I can start figuring out how to drill the pulley for the sds as well.

 

 

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Morgan

http://z31.com/~morgan/s30

http://carfiche.com

[Arif]

Morgan,

I still had to use the bottom half of the stock distributor to drive the oil pump. Scottie or someone else might know a way aroung not using it at all. IMHO I would pick up that distr. just to be on the safe side though. Just my .02

 

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http://communities.msn.com/TurboZ

[Scottie-GNZ]

Warning! Before I posted this, I realized I rambled a lot, so be forewarned

 

I first want to say this post was not intended to sway anyone from a V-8, et al swap or buying top-notch L6 internals. A year ago I was faced with the decision to build up the L28T or do another Hybrid. Having already done the V-8 and L28T, I wanted to try something different and one day might try the VG30-TT route. Only problem is, despite looking sexy, I know it will not match the GN $ for $.

 

I look at it this way. The optimum L28T setup would be with the top-notch internals AND the programmable system, qaulity I/C, fuel and exhaust system, etc. Not everyone can do that, so given a tight budget and the inability to do both, I would (and so did my buddy, Patrick) choose a good used engine and all the right components to make turbo HP the right way. Just would not make sense to build up an engine with forged pistons, etc and then have to skimp on the I/C by using a Starion/Saab, etc or retaining the stock engine management system and injectors or getting a hybrid turbo but having to use the stock DP and exhaust.

 

DRAX, you are very observant in noticing that Patrick did not go cheap on certain things, i.e., the right things. As far as how much $$, I could not say because he had bad dealings with the body shop and had to take it to another shop to have things redone and finished. The detail work was all done by him since he had a lot of time on his hands. The shortblock was taken apart, boiled, checked and reassembled with new rings and bearings and the head had a standard valve job. Where the $$$ were spent was: SDS F, turbo, exhaust, Spearco/plumbing (see pic below), fuel system that consists of Pierburg pump, rear sump on tank, 1/2" feed line, fuel rail SX FPR, quality oil cooler and lots of braided hoses, AN fittings and ceramic-coating. For those of you planning a buildup, thats the stuff that kills your pocket.

 

As for comparing my car with the T3 wheezer, he and I have have done that a 1000 times. My mph (110.97) was an indication of 12.70s instead of 13.02. Patrick's 60' was .31 quicker and his car is 150lbs lighter. The T3/5-spd combo spools so quick that launching my car was damn near impossible. By coincidince, both cars gained about 27mph in the 2nd half.

 

Morgan, having gone both routes, I would go with the turbo shortblock. The NA block will work but is more prone to breakage if you detonate because of the rings. This is the perfect example of why it is so critical to keep the heat down and eliminate detonation. Patrick made considerable more HP with less boost!!.

 

As for the distributor, you do not need it. Just fab a cover out of 1/8" aluminum. Note that the distributor does not have a gear and that is because it is driven. The oil pump is driven by a gear on the crank and the distributor is driven by a shaft off that assembly.

 

There is no way to say how long it will take to tune an SDS. 2 identical engines could react differently to the same map, but they should be in the ballpark. Once we got the right injs for Patrick's car, it fired right up and the maps I put in are unchanged. The SDS shields you from a lot of the complexities of tuning. You have to determine a starting point for fuel based on engine displacement and inj flow rate. Here is my philosophy on tuning the SDS. Once you determine the starting point, build a fuel curve for driving w/o boost, based on the engine's torque curve. Build an iginition map based on the stock ignition curve with an initial of 20BTDC and a ramp up to about 39 at 3200 and then 39 all the way to redline. Once you have good driveability w/o boost, then you can build another map for adding more fuel based on boost demand. I like to do it in stages by limiting the boost to say 5 or 6#, tune, then up the boost to say 10#, tune, etc. As you add boost, you need to program in ignition retard based on boost. Here I use a guideline that says at 15# boost, the total ignition should not exceed 24 or 25 degrees. Since you programmed in 39 from 3200RPMs on up, then you need to build a retard curve that starts reatrding the timing at say 3# boost and ramp up to retarding 15 degrees at 15# boost, resulting in a total of 24 degrees. All of this is a starting point and the neat thing about the SDS is using the rich/lean to change the fuel mixture on the fly. You do not need to know or concern yourself with all the possible data points, as it takes of that. You just need to tell it how much fuel at what RPM, How much timing at what RPM, how much more fuel at what boost, how much retard at what boost. Those are the key maps, but you can also program for retard based on knock, cold start based on ambient and water temp, etc.

 

Well, I am rambling again and that should be enough to chew on or confused and maybe even scare away potential users. But, you know, if you are scared of this or do not have the patience to fine tune, then you probably do not want a programmable system.

 

 

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Scottie

71 240GN-Z

http://www.mindspring.com/~vscott911/gnz.html

[Guest Anonymous]

I didn't think the distributor was necessary, as there are no gears on it, and it just bolts in with 1 dinky little bolt.

Did you use an OE set of wires or custom made? If oe wires, from what car?

 

I'm not scared of it at all, I read all the sds instructions thoroughly last night and it's pretty straight forward. I'm more impatient than anything, and I don't want it to take a month to get it running nicely

 

I hope people take your advice to not skimp on their turbo or intercooler too. That's the best place to spend money on any turbo car. Just nobody believes me when I tell them their stuff blows!

 

 

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Morgan

http://z31.com/~morgan/s30

http://carfiche.com

[Arif]

Scottie,

Thanks for the clarification on the distributor. When I had my engine put together the mechanic said I needed it to drive the oil pump.

Morgan, the system is really easy to use just don't be too impatient to get to the boost. I concentrated on getting the ehgine to idle and run w/o boost for awhile.

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http://communities.msn.com/TurboZ

 

[This message has been edited by Arif (edited December 18, 2000).]

[clint78z]

Yes I will also put a plug in about getting boost . Take the wastegate an wire it open so no boost occurs . Tune you engine so it runs perfectly . Then gradually ease into increasing boost . You can't take mistakes back at high boost !!

 

Those are awsome #'s, my New Years resolution is to get mine running . It's a fair commute to work on my car, but slowly it going back together . Hopefulley I can get my 2+2 into the 12's .

 

[This message has been edited by clint78z (edited December 19, 2000).]