tweakgames

Hello.

I have a 2000 LS1 that I have done KATECH rod bolt and a dry sump with a T101A behind it all. I have ported 5.3 heads, bar lifters, upgraded springs, cam, blah blah everything needed for the higher RPM I am trying to run on the way.

I just now got to the point of looking at intakes and am taken back by the price of the FAST 92 or 102 intake manifolds. I have an LS1 intake right now that I hears is just molded poop painted black, so I need a new intake and injectors, but I am wondering if the engine will completely fall on it's face with an LS6 intake? I use this for pro-am drifting, autox, and some road racing, so I like the idea of keeping the throttle body smaller and having better resolution of input with my right foot. But if I'm going to lose tons of power at the higher RPM I will bite the bullet.

This is in a 88 Rx7 so I have hood clearance to run the LSXRT (truck) intake manifold if that will help any. What are your opinions on the matter?

Thanks.

soundengineer

iTrader: (16)

Stock style Intake Manifolds are done by 6800 ish maximum...even the FAST 102's fall off quickly past 6800...
a stock size TB will choke you off as well...
the bigger the TB the better its going to be at higher rpm's
it takes more CFM to make power at high rpms

if you want to spin to 7k+,you need to go to a single plane intake


its all about runner length and design..

zacht

iTrader: (18)

^agreed. i was going to say the same thing about stock design manifolds.

also. why have katech this and that and all these cool parts and not top it off with something sweet??? let that motor breath!!! run it for now if money is the issue, intake swaps are easy, but youll for sure want something nice on top of it

tweakgames

Because it is a racecar. The katech rod bolts and dry sump are reliability parts, not performance. I was bouncing or riding the stock limiter almost every run. (We did lower the limiter to 6k though, again in hopes of keeping the engine alive)

But now it is time for some performance, I am trying to keep the car under 2600 lbs, so I would rather not run the big aluminum intakes if those are the "single plane intakes".

Thanks for the posts guys. It seems like most the people running lsx NA are running the LSXR. I might have to just shell out the cash, there goes 12 more tires.

soundengineer

iTrader: (16)

Highlighted in red is the exact reason to use a single plane intake
they arent terrible on weight, and they make power in the upper rpm's where you will spend most of your time

if weight is a BIG concern, go with a sheet metal intake... best of both worlds... lighter weight, good at upper rpm's, you can get ones that face up for a carb, or get ones that face forward for a stock style throttle body

tweakgames

If I remember correctly, I did a quick search on sheet metal intakes a bit ago and they were all at over $2000. Unless I am missing something?

soundengineer

iTrader: (16)

I never said making power above 7000 rpm was going to be cheap.

cheaper with a cast aluminim piece, more expensive with a lighter sheet metal intake

Choose your battle, Money or weight

tweakgames

Alright, well I think I may be fine with the LS6. Not really into making power past 7k, just need to be able to get to it without it falling on its face.

soundengineer

iTrader: (16)

you can believe what you want, but a stock ls6 intake will not make power past 6500~6800 on any cam that will fit under a set of stock heads with stock pistons

theres a LOT more going on to his setup if he is making power up to 7200 rpm.


Runner design just doesnt support it.

and I have tuned hundreds of cars....and umpteen different combos...

Grr

iTrader: (2)

LS6 would be fine for awhile, they are easy to sell if/when you decide to upgrade. You really do need a single plane for that setup, what cam is in it?

garygnu

you can find a ls6 or BBK intake for $350 or less used.

badassracing

iTrader: (13)

I know of a car that made nice power up to 7000 with patriot 243 heads, ls6 intake, ported TB, and a 230/236 cam. It was run up to 6700 and was still making power so we raised the limiter to 7200 just to see what it would do. I dont remember the exact numbers though.

bww3588

iTrader: (49)

I think everyone is missing the point...power may fall off after 6500 but I don't think he is concerned with building power at 7k. Just wants to make sure it's not going to fall on it's face.

I had an ls6 on my car with an ms4 cam, power peaked around 6200 but flat lined to 6600 where it fell off, but it didn't fall off a cliff. I shifted at 6800 with the limiter on 7200.

JakeFusion

iTrader: (7)

Just saying you have a cam and springs doesn't mean squat. Those have to be right. By right, I mean you need the proper VEs, lobe profiles, and springs to handle the abuse. A cam in the low 240s intake and high 240s exhaust will produce what you want with a very late IVC. I'd say 50 or 51 to really push the intake out of it's optimal runner "haven."

The FAST 102 is what I would go with and a cam with endurance type properties (hybrid hydraulic/solid roller lobes) like EHI/EHX. I'd personally go with a Comp Cams custom grind and do EHI #12674 intake and EHX #12692 on the exhaust. I'd then do a 110+0 LSA. It would spec out to 243/249 .675"/.675" 110+0 LSA. It's no more expensive than the LSL or XE-R or LSK lobe cams you see on here and is actually more stable.

Heads. 5.3? You need bigger runners that flow a LOT of air. I'd go with AFR 230s, PRC 227s, or AI Ported TFS 230s. I'd also run the lightest valve you can run on them. Hollow-stem stainless would be preferred. I'd also run a spring like the PAC 1521s which are good to 700 lift with Titanium retainers. The PAC 1521s are probably the best springs available for the LS1. I'd then run the stock LS rocker arms with the Comp Trunion upgrade. Since it's a race car, anything you may have heard about high lift or excessive spring pressure won't matter. You want lightweight over the valve.

Plus you said you have link-bar lifters? Which ones? Morel Hi-RPM 5294? That's what I'd run.

You can run 7500+RPM in a setup like the above without going Single Plane.

I'd also get an ATI Super Damper and the stiffest pushrods that will fit in the heads. PRC and AFR will take 11/32" .120" Wall Mantons. The TFS heads will take 3/8" .120" wall Mantons.

tweakgames

Thanks, but I already bought ported 5.3s and the whole new cam/springs/lifters package from Phil at advanced induction. I don't know exactly what cam I am getting, but I trust his decision. He know's I am going for high RPM safety.

I did all last year with 321 HP, so anything above 400 rwhp I will feel extremely spoiled.

I have the dampener, it came with the dry sump, I forget to mention that because I forget it's an upgrade.

The quote says,

CompCams 15956-16 Limited Travel Tie Bar LS Racing Hydraulic Roller Lifters
Hardened 4130CrMoly 1pc Racing Pushrod 5/16" x .080 Wall x 7.xxx (3/8" Req. Machining Clearance)
BTR Dual Spring Kit - .650" Capable w/ Titanium Retainers
Manley RaceFlo SS Valves 11360 2.000" Intake/11361 1.550" Exhaust

This isn't a max power max effort setup, it's a, I may need to bounce off redline for 5 seconds, on a banked nascar track, at highspeeds, 20 times an hour, and the engine needs to be able to do it again next hour. lol I don't ride redline that much that often, but I would like to build it for that. If I'm next to someone that is slower than I am (will most likely happen more often this year) I can't shift up because I will grip and straighten out and get a 0. I have to do a dance of e-brake and redline. lol

Also I have not tested it yet, but I have been told I should be able to shift when I hit the rev limiter with the dog box. If if falls on it's face before redline and has trouble getting up to it, that would be pretty annoying.

Also yes I got the 13702-Kit LS Roller Bearing Trunion Kit.

tweakgames

Alright, well thanks for the info everyone. I think I will just get a ls6 or BBK as stated above, unless I can find an extra $1k laying around. XD

Thanks.

zacht

iTrader: (18)

i wasnt questioning why you had those parts in your build. i was getting at, your saving a few bucks and hurting the performance of the build by topping it off with a LS1...im a huge budget guy...and can understand tossing one on for cheap and "itll do for now". its like building a new house and leaving the roof as tar paper...will it last? maybe for a little while...but you wont be happy for very long with it that way...

2JZFC

iTrader: (26)

I think your analogy is a little extreme. Not everyone doing a project can afford to get all the ultimate performance parts all at once. I have a turbo 6.0L in a 3050# Fox, started out with an LS1 intake and feel it is now time to go to a Pro-flo. However, the car trapped 149mph. Use your favorite HP calculator to figure out how much HP that it is. Would it have made more with an LS6, FAST, et al? Of course it would, but it made more than probably most projects will end up with, especially the wildly popular budget-minded turbo 5.3L folks.

So IMO, for folks on a budget, especially 5.3L turbo cars looking for around 600hp or cars with hood clearance issues, it will do just fine until you can spring the coin for an upgrade.

zacht

iTrader: (18)

yes, totally agree that its "fine until you can spring the coin for an upgrade" i said that earlier. his build doesnt sound like a "budget" build from the get go, with katech parts here and there, dry sump, link bar lifters. i got nothing against putting it on there for a while, the point of the arguement here is he said he wanted upper rpm and durability (hence the cool parts) everyone here has said that even the stock design intake doesn't flow that well up to that rpm (including fast intakes). basically the ls1 is fine for now, but it looks like he's springing for a ls6 or equivalent.