I'm completely rebuilding a 99 Ta ls1 motor with T56. I just need to find out if there are any more mods or tricks to give more naturally aspirated power before we dyno tune it.

Currently have Milled & Fully ported 243 heads, Tsp 228/232 cam kit, lid, fast throttle body, fast intake, Mac long tubes, y pipe with no cats to borla duals.

How much is to be gained over replacing the Y pipe with an x pipe?

Will an underdrive pulley dim the lights at low rpm?

Maybe a ported maf? Or is that a waste?

Bigger fuel injectors?

Someone said I could upgrade the headers as well, but I think it may be a waste of cash for only a few hp gain.

I have an older fast intake and TB, I don't know the mm. I Will measure tomorrow

Keep in mind this is a daily driven...or almost daily street car. Thanks

 

Not sure what pound injector your running now. And unless they recently came out there was never Mac LT's for a LS1, I use to run the mids on a older car, though it was a popular header when the LS1 first came out jumping to LT's could get you another 10. UD Pulley will definitely free up power(lights will be fine) and a 85mm truck maf can be found for $50 on Ebay, that will also help(you'll need a retune). Depending on what fast and TB you have, possible porting both or going to bigger could help.

 

I'd get the fast ported and do a UDP.

 

UD pulley might dim the lights with stock idle, but your setup has a raised idle for the larger cam, the idle being higher will mean that the alternator sees likely stock setup rpm after the UD pulley.

Porting a MAF is a GREAT way to completely ruin calibration unless whomever ports it has the new MAF tables to put into your tune.

Far as injectors, is it lean? If it is not lean there are advantages to running an injector not greatly oversized. Displayed DC in a scantool is NOT accurate.

Do you have any measures of how it runs now?

 

Sounds like a good amount of mods already but there is plenty of supporting stuff to be done as well. The rest of the drive train should be addressed as well with a full bolt on H/C car. Particularly the 10 bolt. I would take it easy (no hard launches, aggressive 1-2 shifts, sticky tires etc) before you have a plan to address is. Clutch, Tick Master cylinder, shifter, etc, etc. Lol....it never ends.

 

I'd venture to say with an HCI the stock LS1 injectors are in dire need of upgrading.

 

Like I said, "is it lean?"

 

They are definitely maxxed way out. You need bigger ones for a HCI engine.

 

I bought the car last week for cheap and the motor went the next day. It had a cracked piston ring and blown head gasket.

So motor is being machined, resleeved, crank turned, new beArings, plugs, etc.

It had 853 heads, so I bought some vette 243s, they're getting ma valve job, milled, and fully ported and polished.

I.bought a Tsp 228/232 cam, with prc duals, hardened rods and ls7 lifters.

It came with long tube headers, the seller said they were Mac. It has no cats, a y pipe to Borlas.

Here's a pic of the fast Tb and fast intake.

 

I would ask the tuner for sure. If you are using a tuner that has experience with the LS platform they should be able to tell you. My initial thought is that it will need injectors and even perhaps an upgraded pump. I know that when I spoke to Pat G about my build plan he was able to tell me the that I would need an upgraded pump just based on my parts list ( I already had injectors).

 

My stock injectors are maxed out w/ my bolt ons in sig let alone a heads/cam setup.

 

You could probably take the maf and matching injectors from a newer truck in a junkyard for cheap enough. But I would just get new injectors (big enough for e85) and a card/slot style maf sensor, personally.

Get some real headers (so you know the brand and size), 1-3/4" stepped to 1-7/8", or 1.875" stepped to 2" would be great for a n/a street car.

Absolutely ditch the Y-pipe in favor of true dual exhaust with an X-pipe. I'd run electric cutouts after the X-pipe, and borla xs mufflers after the cutouts. Have it all stainless steel up to, and including, the mufflers with aluminum pipes after the mufflers going back and over the axle.

Get the intake and throttle body ported.

If you're already getting new pistons, shoot for higher compression and burn corn... You aren't out of naturally aspirated modifications until you are running high compression and using e85.

If it's not available, or practical, that's definitely understandable, but e85 and compression are the next step in the quest for naturally aspirated power.

How about the little things? Did you have a one piece billet reluctor wheel welded to the crank (not for performance, but durability)? Electric water pump? Lightweight oil/high volume oil pump/high capacity oil pan? A real fuel system? Vacuum pump? Ls6 valley cover/pcv/catch can? Lots and lots of little things that add up to a successful naturally aspirated motor.

You aren't anywhere near being out of things to do naturally aspirated, sir. Keep your head up, you still have a long, hopefully fun, journey ahead of you.

 

get some 3.73 or 4.10 gears

 

Good call!!

What about CHRS1313 Ram air?

 

Whatever you do make sure you take that FAST intake apart. I lost my previous engine when I bought a used FAST 90mm from the classifieds. The previous owner grenade his engine and neglected to tell me. As soon as the intake got to operating temp it sucked a bunch of aluminum into the engine. Learn from my $2k mistake.

 

A 383ci rotating assembly would add more power....

 

How well those heads are ported will determine a lot. Lightening and strengthening the valve train is often overlooked. Although it gets pricey it increases reliability and more HP by virtue of higher RPM and the resultant power of valve control.

 

There's only three ways to make power naturally aspirated... Displacement, compression, and rpms.

If you are set at a certain displacement, then you have to add more compression and/or more rpms. If you're rpm-limited, then you have to add displacement and/or compression. If you are octane/compression-limited, then you have to add more displacement and/or rpms.

Careful selection of the bearings and tolerances and oiling system will increase rpm potential, as well as help with reliability.

Piston selection and the fueling system can facilitate the additional compression, if you have access to the octane.

Other than that, yeah, a 383 stroker kit will definitely increase the potential to make power.

 

IMO one COMPLETE thread would serve you better than multiple with half the info in each.

QUALITY of the port job is more important tan the fact they are "ported" and "ported and polished" is a term usually used by those more familiar with some 45yo "2.02 fuelie" heads or salesman.

Possible it was lean due to tuning or failed/maxxed out injector and that cracked the ring land, since you don't know and it is a risk with the new motor step up to something bigger but don't go overboard, despite what the forums say 30lbs will feed 500rwhp through an automatic. The datalogger displayed duty cycle is not necessarily accurate and the old 85% rule is a steaming pile of bull.

Displacement is worth considering if you need a crank and have the budget, otherwise it is about the most expensive HP per dollar you can buy.

 

A 383 stroker kit sounds great if I could afford it. I paid $4500 for the car and another $5700 dumped into the engine, including labor and dyno. My funds are stretched thin.