EM's LTs are sweet!

 

I've used both CSI and meizer with alot of sucess. I think I like the CSI best.

I run them on a relay with a ACC power to turn on the relay.. Everything fuel pump, alky injection, waterpump is completely automatic in my car that way If I let my girlfriend drive it or something I don't have to tell her to flip switchs.. then get nervous thinking she might have forgot.

 

The Crane/GM 846 cam has a little more lift and duration than the HotCam;

222/230 Duration @.050
.542/.563 lift with 1.6RRs
112 LSA

 

I have 400 at the fly wheel without nos 415 rear wheel with 456 torque on the gas. Sure keeps the kids in their Mustangs at bay. I had some porting on the intake and exhaust but the heads are stock. I have a new top since this picture, looks a bit ragged here. If I was doing it again I would beef up the bottom with forged thingies.

 

Scaryfast:
Our LT1 is a 383 stroker, puts out 505 at flywheel without NOX. More than I can handle naturally aspirated. I haven't had the guts to hit the 250 shot of Nox yet.

I just had a couple of thoughts from our build up job, but might have a few more depending on what "track" you'll be on: 1/4mile, oval, autoX or F1/road race type.

IMHO, here are a few ideas that should work on any of those tracks:

1. Be REALLY careful with the bottom end. There's significant difference in hp output and durability depending on how the same components are assembled. For example, a high quality, lightweight crank that is well balanced could add a good percentage of horsepower (i.e., it robs less hp from the engine) than if it is not balanced, and a much greater output than a heavy, not-so-well balanced crank.

So, even staying with stock components, weight match the pistons (machine or add heavy metal if they're off) & carefully balance the entire rotating assembly. Go for the best bearings and make sure the engine assembler uses top grade lubricants. If you can afford a little extra, this is the most expensive and difficult part of the engine to "fix later" so don't skimp here. Lightweight crank, pistons and rods don't sound as sexy as a larger TB, but the bottom end is the foundation and a bit extra $ here now is probably a good investment. You can upgrade a TB later very easily, but you can't upgrade a piston easily!

If you build a solid bottom end, it will handle whatever power your top end can generate. But around our parts, a certain famous builder loves to strap on big heads, blowers or NOX to get big HP numbers on dyno and then the drivers blow out the engines in a few months because nothing was ever done to the bottom end!

2. Consider an oversize radiator (some have built in oil coolers) plus an electric water pump. The cooler engine will allow the higher compression you're pushing with less chance of timing retard from anti-knock sensors due to premature ignition (less an issue on 1/4 mile & autoX, much bigger issue on long races) (make sure any gaps between oem housing and new radiator are filled with heat tolerant foam to ensure more air flow through radiator and not around it)

3. Invest good $ in quality porting and matching your TB, intake and heads. All three need to be matched and, again, the quality of the work makes a huge difference. It's more art, but the science of the airflow measurements tells the tale.

You might consider an LT4 intake instead of the stock LT1.
It sounds like you already chose the heads, but I like the AFR 200 race heads for the range of power you're looking for.

4. Cam choice is crucial. Spend time with Bob on your custom setup. Make sure the lift is ok with the heads/valve train. Sothpaw is probably right about the timing chain, I went with Cloyes on my builder's recommendation and no problems. Focus on where in the RPM range you want your torque.

5.I'd suggest suspension changes while the engine's out if you're doing auto-x (RD Racing's camber brace, maybe X brace and/or upgrade the bushings).

6. You might need larger injectors, be sure they're flowed and matched.

7. I like the TPIS headers and Dr. Gas X pipe. No problem on install and really performed (with a borla cat-back).

8. For a replacement EPROM, TPIS will custom program a prom for you. They'll do upgrades as you change your setup for a nominal cost. Honestly though, I have no personal experience because we put in the ACCEL/DFI standalone computer to control the engine. I would defer to anyone else who's had personal experience in this area.

A car's performance is limited by its weakest link. You haven't mentioned any change to transmission to handle this power, or to the wheels, tires and rear end to keep the power on the ground.

Finally, don't regret later that you skimped on safety. Make sure your shocks are in great condition, install braided SS brake lines, purge and refill the entire brake system with high quality brake fluid (if you do autox or longer races you should consider very hi-temp fluid, pad upgrades and maybe caliper and rotor upgrades (Grand Sport calipers are cheap and good!) if it doesn't blow your class), a roll cage and harness are worth the money.

I probably forgot a few things, but everyone else will remind me. I guess I probably unloaded a bit too much, please don't flame me too much if I did. Just trying to share what we learned recently. MJI

 

The LT4 intake won't work with LT1 heads, for all practical purposes.
You would not want to install the camber brace until the engine is back in the car.
Bushing change can be done equally easily w/ or w/o the engine installed.
You do not need bigger injectors w/ your set-up, it would be a waste of money and of no benefit, Scaryfast.

 

Scary,

Yes you would need a different timing chain than the LT1 if you modify the cam (new springs in valvetrain) or port heads (allows you to rev it higher).

None of the road racers run an LT1 chain. All have rollers. My tuner claimed he broke LT1 chains road racing in show-room stock in 1992--ported heads but no cam /spring change, 6000 rpm max. Broke in 12 hr of 24 hr endurance race.

A new "stock replacement water pump" is exactly what I did along with the recommended Cloyes HD timing set. And that set up has destroyed the engine. Granted it is rare, but that may be just my luck or it could be that the replacement waterpumps are not up to snuff.

I strongly recommend either keeping your stock pump (known to be good--you could re-hab the rubber so it won't leak) or going electric. Electric is obviously the safer choice. Meziere Heavy Duty is what you need. But be warned that your car will run hotter.

I've concluded that the best thing to do is to keep the car stock and don't use GM's replacement water pumps. Otherwise there is a risk, and I can't say how great it is--maybe my pump was 1 in 100,000.

 

Look at the Comp Cam 224/230 cam with the 3100 series lobes

224/230 Duration @.050
.606/.622 lift with 1.6RRs
113 LSA

They can make it with whatever LSA you want. You will need some stout springs for this cam... they recommend the 977-16's, which is what I have.

Mike

 

Man this place is great. The help keeps on coming.

BTW, a few have asked about NOS or forced induction - NO WAY! This is and will remain a normally aspirated car.

Masterspy - all good advice. A few comments:

Suspension is already done. The car is all set for road racing (although there are always improvements to be made) with custom valved coil-overs, brakes, bushings, new camber and toe bars in the rear, custom alignment, tires, cage, gutted, rear gear, etc. The motor was the last thing on my list and the time has finally arrived.

I agree about the bottom end. However, I am planning on doing a two step plan even though it involves redundant work and cost.

Step one is what's going on now, using stock bottom end from a donor car and adding some easy power. I want to finish the season and that's the only way to get up and running quickly. I really don't care if I end up breaking this bottom end as it is temporary, as long as none of the new components (heads, cam) get hurt. This thing will be sold cheap or kept for a spare when the new motor is ready.

Step two is rebuilding my current bottom end over the winter. That's where all the heavy work will be and I don't want to rush it. It will be all new components, balanced, blueprinted, etc. That's why I'm not buying anything now that won't transplant seamlessly onto the new block. I have no plans to increase the displacement, but that decision may change depending on NASA's new rules coming out soon.

As for the cam, Bob has a profile in mind that works well with the heads. We're going to iron it out today, it should have plenty of lift to take advantage of the best flow (around .550 for these heads). We're adding beefier springs as well.

Also, it looks like I am adding the water pump and timing chain to my list while the motor is apart.

 

Ok, I'm a little confused now. Are you saying do one of two things:

1. Keep stock pump and stock timing chain - is this possible with a cam?

2. Add electric WP, remove shaft from block, and switch to better chain?

If I need to stay away from the Cloyes/LT4 chain what's a good suggestion?

 

I am still using the stock pump with stock chain on my 92. Here are my part numbers:

Timing chain (GM OEM) Superior Chevy 10128485 $25.42
Cam sprocket (GM OEM) Superior Chevy 10128349 $29.24
Crank sprocket (Cloyes) .014 Oversized Cloyes S505 $19.28

Mike

 

Cam specs are in:

Comp Cam custom grind

230* / 236* duration
0.576 / 0.571 lift
112 LSA +2* advance

Due to new cam I have to order a new electric pump, can I just use the stock chain for now?

 

You've got it.

1) Stay stock. old pump, chain, cam, heads.
2) Don't. Go electric, and a Cloyes doubler roller is fine.
3) Don't. This might be a little dicy--but go with old pump & Cloyes LT4 and hope that the old pump never locks up.

 

Where are you getting this info about electric pumps.. Did you have one fail?

I've never had any fail on any of the vehicles i've used them on. I've used both CSI and Miezer with really good results. The only reason I can think for the pump to fail is not using a good relay with a good voltage supply. Also make sure all your crimp connectors are extremely firm, solderd, and waterproofed.

The car should run cooler with a electric water pump for the simple reason that the pump is spinning faster than a stock pump at a idle and cruize and doesn't suffer from cavatation at wide open throttle like a stock pump does.

I've also used the street pumps (as reccomended) from miezer.. not the heavy duty pumps (not reccomended for the street by the manufacturer)

 

I have ran both the CSI (Old LT4 HC motor) and the Meizer HD (Current motor) and have yet to have a problem. The electric WP provide free HP and will not tear up the timing set or Opti spark in the event of a failure. My car is a daily driver 70 miles round trip every day and does road trips just got back from a 1300 mile trip (27.5 MPG Hwy for the second straight trip BTW). As for the WP shaft I left it in place and keep the coupler in my center console, just in case I am ever out of towm and need a WP fast I can go back to the stocker.

Scary I think the cam you selected will work well with the 383 plans it is similar to my 306 grind and I love my cam. I used the LT4 timming set with no problems but again I have the electric pump.

 

The motor's out, heads should be here ~Wednesday, EM headers by Thursday, and the other stuff (water pump, oil pan, etc) even earlier.

This should all go back together by next weekend if all goes well!

I still need to figure out what to do about the calibration.

Will the car run at all with the stock programming?

 

Yes, but your idle and part-throttle will be a little rough.