jmac636

iTrader: (8)

I had my car dyno tuned a few months back. Seems to be missing some torque. Its a rebuilt 5.3 liter L33 with 243 heads. C6 corvette exhaust manifolds, ls1 intake, tr224 .563 114lsa cam, 2.5" dual exhaust with highflow cats and no mufflers just some import silencers.

Edit: the tune ended up being too lean is why it was missing torque. I bought hptuners and a wideband retuned it myself.

This dyno sheet is before adding the high flow cats and swapping to an LS6 intake.



Here's the engine bay.


Here's the car.

redtan

iTrader: (5)

It's a small low compression engine with OEM iron manifolds.

What did you expect, a torque monster??

Tainted

iTrader: (9)

heres one major thing holding you back an easy 15-20hp. LS6 intake, get one!

99peweterls1

iTrader: (1)

Long tubes if you want to pick up some torque. A lot of things people don't look at is collector length.

jmac636

iTrader: (8)

I am definitely missing some torque but it may be due to the profile of the cam. I probably should have went with a tr220 112lsa. I have an idea how to fix it, BOOST.

jmac636

iTrader: (8)

I'm not talking about peak numbers. I'm talking about the torque missing under the curve.

redtan

iTrader: (5)

Well for one your tune looks whack, because the curve is not smooth but takes a dip in the middle. Probably some knock in that area or going lean.

Who did the tune?

Tainted

iTrader: (9)

The ls6 intake and longtubes along with a retune would easily net you a good 30hp and 20ft lbs across mpst of the board.

jmac636

iTrader: (8)

Local tuner here in houston. I actually was thinking the same thing. I asked about the dip and he said afrs and timing were good but I have done some tuning just not hp tuners and my thoughts were something in the tune wasn't right.

screaminz847

I thought that dip was sort of inherent in some cams. I think the manifolds are probably hurting the most - I'd think you'd pick up close to 40 rwhp and 40 tq or more since you have a cam. Then again, I'm not sure how efficient the LS3 manifolds are, so i could be off base.

Johnnystock

iTrader: (6)

You could buy shorty headers and a LS6 intake...that would net you some good HP.

I dont know but I read somewhere that those kind of ''CAI'' you have maybe hurting the HP too. I dont if you could fab some sort of scoop under the car or isolate the CAI from heat. Just some thoughts

Pray

iTrader: (7)

Your numbers actually look really good. I am assuming this is a stick car. If it is not and has a stock converter it is going to feel very soft on the bottom end. The L33 is no a low compression motor, 10.0 or so. The cam is a hair large and that is causing the dip. Look at where your tq peak is. Kind of tells the story. I doubt it could be tuned out if the guy is competant and had the fuel and timing right. Knock usually shows a little differently on the dyno. That dip is very typical of over cammed LSX's. I had this motor in my 06' Silverado with a smaller cam 215/223 .609 .615 lift on a 112, lightly ported heads, similar intake, headers, cattless Y and other small things. I only made 330/325rw which was up about 75rw from with just exhaust. I was running out of fuel at 5,000 however. Like the other guys said, get a LS6 intake and any kind of header you can on there, do an underdrive pulley and figure out your DCR. I am guessing it is down in the very low 8's. If you used the stock head gaskets then you can replace those with some .040 cometics and get your tq up. Over all I would be happy with what it is making the way it sits. Do the suggested mods and you will be very happy.

low2001gmc

iTrader: (148)

ls6 intake, headers, and stall all would help. 243 heads have 64:45 cc's while 5.3 heads have like 61-62 cc's. no need to change cam but i would mill heads which will increase compression, torque and power .

Pray

iTrader: (7)

What you guys are missing though is that the L33 got new flat top pistons for sure with no valve reliefs and I am pretty sure longer rods. So there was a half point compression bump over the LM7. Stock, the L33 has 9.9-10.0 compression. They changed the cam slightly also. He does need more compression for that cam though. I am pretty sure he can get most of it with a gasket change.

jmac636

iTrader: (8)

I was thinking the same thing. I need to bump the compression up a half point by either milling the heads or thinner head gaskets. I'm thinking thinner head gaskets and then measure for shorter push rods is first on my list. Then maybe an ls6 intake if im not happy.

Tainted

iTrader: (9)

You can get an ls6 intake for $300 or less, id get one regardless. You are down an easy 20hp without it and its a super easy mod to do. Get the ls6 intake!

jmac636

iTrader: (8)

Yeah its a t56 so no need for a stall, lol. I think i fixed my problem. I picked up a 98 ls1 engine almost complete. The only downfall is the 806 heads. I will do a basic rebuild and swap my 243 heads and tr224 cam onto the Ls1. Should be a bit stronger.

Pray

iTrader: (7)

Just remember to use the valve covers and coil brackets/packs from your 243's for your 243's. IIRC the 806's are adifferent bolt pattern and need a conversion.

Tainted

iTrader: (9)

Make sure you get the computer. Tuning is different for 98 cars, i dont know exactly what it is though.

Ryne @ CMS

iTrader: (10)

lol everyone is a tuner these days
the issue is likely just the dynamics of the setup... low compression, single pattern cam w/ stock exhaust manifolds, ls1 intake.... but nevermind it must be the tune....... ....... and before you ask i am not the tuner