home ported lt1 heads(3 angle valve job 2.0 int. 1.55 exh. beehive springs)
matched intake
52mm tb
28 lb. injectors
1.6 rr
1 3/4 lt
lt1 xfi 292
flat top pistons
stock rods
eagle 3.75 crank

What do you guys think about this setup? I was going to spray a 150 shot or get a set of .200 cc dome pistons and spray a smaller shot if I could. What sounds like the better way to get more hp its a weekend driver and what changes would you make to the setup any info will help.

 

Sounds pretty decent. Not sure on the specs of your camshaft but make sure its for higher RPMs. Maybe throw in a set of headers and a nice sounding exhaust!

 

Upgrade to a better connecting rod

Would do some calculating with your CR/cam also if youre going to spray it just to be safe

 

im running 1 3/4 long tube headers through 2 3/4 straight pipes to borla exhaust. There is the link for the cam specs and im not too good at calculating cr how do I do that.


http://www.ebay.com/itm/Comp-Lt1-Lt4-Xfi-Xtreme-Fuel-Injection-292-Roller-Cam-Camshaft-For-1-6-Rockers-/301028027639?pt=Motors_Car_Truck_Parts_Accessories&hash=item4616ab2cf7&vxp=mtr

 

What would be a good rod was thinking about a set of forged h-beams but heard of people having clearance issues.

 

You don't need h-beams unless you are running 7k or more. They are heavier and sling oil all over the place.

 

I don't know exactly what rpm ill be spinning but im sure it will be in the mid to upper 6k. anybody have an idea of what kind of hp this setup will put out? And im running forged I-beams if I can find a set. And what do you guys think about a high compression setup do you think I will make more hp running 11:1 and spraying a 150 shot or running im guessing 12:1 or better with the .200 dome pistons and spraying a smaller shot?

 

Knowing your CR is essential on any build regardless of whether you spray or not.
Get it wrong and risk blowing your engine or having a gutless pig

Also of importance is the DCR,
read this to understand camshaft choice vs CR
http://members.uia.net/pkelley2/DynamicCR.html

Download and install this excellent CR /DCR calculator http://cochise.uia.net/pkelley2/dcrvb6.zip

It only works on actual measurements ; guessing at what you might have will yield meaningless results

 

Not a problem if you buy a quality set with cap screw bolts, most likely going to need a small base circle cam anyway

Nobody runs popups these days.
Current thinking is to run flat tops (gives better flame propagation )
and to adjust the compression with a smaller chamber and / or decking the block to get your required CR.
Hence the reason for knowing your exact specs and a calculator as linked above ,you can play around with the numbers to find the easiest way to get what you want

 

What pistons?

Just about any forged pistons will be fine with a 150 shot but cast or hyper could be a bad idea. Of course of the forged pistons there are some with better ring packages, lighter weight and better pins, ect than others.

Just FYI, flat tops pistons when used with the LT1 58cc chamber will give you over 11.1 SCR with a 3.75 stroke crankshaft. Even with the biggest cams you don't want to get too craxy with compression ratio on pump gas.... runninig over 11.5 SCR on pump gas requires some serious knowlege on engine building, very good parts and a dead on tune.

As for rods look at buying the SCAT "Pro Comp" I beam rods. They are 4340 and use 7/16 cap screws. The are profiled well for cam clearance in stroker cranks. Good rods and priced right.

Whats your budget for this?

I do consulting work on racing engines for people and I'd be glad to help you put a package together that maximazes what you get for your money spent. Feel free to check my back post history and see the engines I have built for people here as well as the threads full of my recomendations on parts. I hate to see people get in over their head on this stuff and I'd be glad to help out.
Will

 

^^ I always look for Will to chime in on these engine build threads.

 

my compression ratio came out to be 12:1 with the dome and 10:9 with the flat tops

 

well guys I finally got my setup together.

home ported lt1 heads(3 angle valve job 2.0 int. 1.55 exh. beehive springs)
matched intake
52mm tb
28 lb. injectors
1.6 rr
1 3/4 long tubes running 2 3/4 exhaust w/cutouts
lt1 xfi 280 instead of the 292
flat top pistons
forged I-beams
eagle 3.75 crank

I downloaded dyno 2000 and punched all the numbers even found a flow chart for a set of home ported lt1 heads and I was shocked at the result. 492 hp@6000/501 ft-lbs @4500
I know these type programs are generous with calculations so I knocked off 60 from both numbers to get a more real world number. What do you guys think of the setup anybody ever built one similar to this and if so how did the car perform?

 

???

 

I'll try to help later if my headache goes away.

 

Wouldnt worry about a number if youre happy with the way it runs-same with flow #s on the heads. Really no way to tell though til yours are done no two jobs are alike

 

Take 20% off to see the approx. RWHP and that's going to be generous...These programed "estimates" cannot consider conditions like temps, humidity, chassis weight, drag, eng temp etc...

The 20% is for loss between flywheel to rear wheel. That leaves you with about 390....Call it 400.

That number is plausible. I've made 4oo with similar upgrades. I remember what it cost me too !
What was the final CR with the current configuration? I see you used the flat tops...another good choice.

The days of 12+ :1 CR on street engines are gone.
The 10.9 is more realistic if the car will be a driver. Unless you have very deep pockets and CAN afford to fill up from barrels every week...I'd sure stay under 11:1 or you'll be getting 55 gal barrels of Sunoco 98 (260gtx) delivered to your house for the Corvette. ( I wish)

Mine current motor came out at 10.5:1 and that was right about what I was looking for. That range yields the performance without being forced to buy the expensive feed for the beast. 93 octane will be slowly going away and the 89 & 87oct are almost useless to a built engine. As is, I have to back out of timing to drive city streets in the summer to prevent too much knock from the available fuels when the eng temps get up there near the limits. When I CAN drive in more normal temps, I can dial in the full timing advance and run fine on 91 oct or better. This engine got "spoiled" when it was brand new by getting av-gas for the first few months....living by a small airport gave me access to all the Cessna gas I could pour in the tank...ran GOOD too ! The good 'ol days.....pre 9/11. Can't drive into the airport anymore.

Anyway, IMO a motor like that (12:1)is good for nuthin except the track. As Oz stated, there are many ways to adjust that down if needed be. Even a thicker gasket helps, BUT you have to look at the quench very carefully or its all for not.. The "rules" for this are pretty well known. Its just doing the math, something that I leave to the machine shop ! They are farrr better at those multiple digits behind a decimal pt.

I hope that quench and all that was taken into consideration? if that's not done properly with these "designed" combustion chambers, all that compression is wasted and will end up causing the engine to knock and rattle itself to death. Thank God for the forged goodies you used ! Good call there ! Its well worth the added expense to go with forged bottom end.

Don't forget the "tune". None of it matters until the programmer gets a hold of it.
All in all, sounds like a good build.

if you don't mind telling,. what would you est your total cost in parts to be with the current set up? I know you have tons of labor in this, but I was curious about the budget and how it compares to others for similar results?

 

paid right at 3000 for parts and machine shop cost