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Discussion Starter #1
I've been debating for a while about what I'm going to get done with my engine. I have considered turbo, but I have some doubts about it. A professionally re-built turbo engine with T3/T4 turbo, intercooler, SDS, injectors, big TB etc. wil cost about $7k US, if not more. We're not even getting into clutch/flywheel/5-speed yet. Another downside is more weight on the front, and the possibility of catastrophic engine failure.

I'm more set on a performance N/A rebuild. The engine will be professionally built by a competant Z shop who build Z race cars and work on tons of Z's as well. My goals are to have 250 hp (more is good). This would put me in the power/weight ratio of Porsche 911, BMW M3/M5. I definately want to be in the 13's with a 3.9 rear end. I know carbs can make more power, but I'd rather retain the refinement/reliability of FI. Here is what I'm thinking of:

- L28, rebuilt, bored to 2.9L
- 10.7-11:1 compression ratio
- 240 rods/flat top? pistons
- Port and Polish with shorted valve guides (50% more exhaust flow, 20% more intake flow)
- Bigger valves
- Port match/extrude hone intake manifold
- Heat shield b/t headers/intake
- Big bore TB
- Upgraded ignition system (MSD etc.)
- Rising rate fuel pressure regulator, bigger injectors if necessary
- MAS airflow system/ or turbo afm/ or SDS
- Performance camshaft (grind??)
- Headers/2.25" exhaust/free-flow muffler/no cat
- K&N cold air intake
- Electric fan
- Shave 5 pounds off flywheel

What do you guys think? The race cars they build have engines like this, but have heavier cams, 6 throttle bodies, 13.7:1 compression. They produce 320 horses.
 

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wooow.
sounds like most of the stuff I want to do.

I really dont know what HP numbers you'll get but it sounds good to me.

why do you want to keep 3.9 rear end though?
Fuel economy?

goodluck.
how much do you think this will all cost?
 

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Discussion Starter #3
I think it'll be north of $7k. I was quoted at $5k on the engine, but when you add in some extras, polish this and that, tranny, clutch, rear end, etc. it adds on to the price.
 

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I would keep your compression at 9.5:1 or slightly less,10.7:1 or11.0:1 that you qouted will be to much for a street engine on pump gas.Unless or course your engine builder has experience with this combo and is willing to gurantee his work.IN WRITING.Horse power is in the cylinder heads on these motors so have it done by someone who knows L heads,the difference between a properly ported street head and a race head ported for max flo at full valve lift is quite different.A properly done 5 angle valve job on a Serdi machine will help out here to.You might want to try a 2.5 inch exaust also.
 

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my su's are extremely reliable.. especially after you rebuild them once or twice you really get to understand them and never need help with them and can tweak the isht out of them.. needle height etc.. f.i with all that engine work youre gonna need more fuel.. where you gonna get it? the rising rate regulator may solve all that but it may not.. im no expert on F.I... but maybe you need programmable engine control Cha Ching.. $$$$ z therapy carbs are 600 bucks.and should be good to 3 liters.. supposedly stock su's are good to 3 liters with the right needles.. whats the benefit of 240 rods? i have a complete 240 engine and a complete L28 and im going to make one engine out of it F54 block and E88 head.. why 240 rods? ill also be using bigger pistons etc.. can you email me and explain that and the shorted valve guides and bigger valve thing please.. thanks if you can.. if you cant @#&%* off .. just kidding..
 

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...i dunno,
just got my '82 zxt rebuilt $1700 (shipping was included)....i think i would just get a turbo eng (or the whole car) and throw away or part out what i didnt use....rebuild it ,intercool it....mildly....big pipes in and out........youll prbly have 300hp
i would think you could do it w/new (reman) turbo and injectors and whatever else you need for $3-4000...... (pull it/put it back in ....pipe it yourself..)......s
 

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I am going a similar route. Here are some issues and changes I would make:

-10.5 is the most I would go on compression and that is with a P90 head shaved.
-Stick with the L28 rods and go with JE or ROSS forged pistons. (I know most people dissagree with the forged piston on the street, but they are getting old info.)

-Stock L28 valve sizes are fine. Too big will kill low end flow.
-Jet Hot coat the header.
-2.5" exhaust for sure

I would think about scrapping the FI. It was not meant to make power and it will limit you. The computer is not sophisticated and there just is not enough flow. I prefer the Weber 40mm or 45mm triple setup.

Get the lightweight flywheel. 10 lbs I think. 13 lbs lighter than stock.

I think you can hit the 250hp goal with some good porting and a proper cam. I doubt you can get that with the FI in place.
 
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