LSx heads/topend suggestions

[Phish]

I believe my winter project for the RX7 is going to be something with the tompend of the motor. Right now its a Fast 78 with with a 232/234 cam. Currently running a milled and hand ported 862 head on stock bottom LQ4. It will definately get long tubes on it over the winter as well, but i am curious on what i should do with the topend. Should i keep my setup and do something like and aftermarket AFR or ported Head from TEA or should i go the TEA ported LS3 topend route? Still planning on keeping it a nitrous car. Thoughts on what woudl be the way to go and why?

[StreetSweeper]

I believe my winter project for the RX7 is going to be something with the tompend of the motor. Right now its a Fast 78 with with a 232/234 cam. Currently running a milled and hand ported 862 head on stock bottom LQ4. It will definately get long tubes on it over the winter as well, but i am curious on what i should do with the topend. Should i keep my setup and do something like and aftermarket AFR or ported Head from TEA or should i go the TEA ported LS3 topend route? Still planning on keeping it a nitrous car. Thoughts on what woudl be the way to go and why?
I think the first thing would be to figure out what your goals or intentions are.

[Phish]

I ran 7.48 @ 93.5 this weeknd all motor at eddyville. I was hoping i could get into the 6's on motor with a head/headers combo over the winter. Not sure if that would be possible but i would like somthing that could get me there or close.

Would also be stayign a nitrous car, so boost would not need to be taken into the equasion.

[StreetSweeper]

I ran 7.48 @ 93.5 this weeknd all motor at eddyville. I was hoping i could get into the 6's on motor with a head/headers combo over the winter. Not sure if that would be possible but i would like somthing that could get me there or close.

Would also be stayign a nitrous car, so boost would not need to be taken into the equasion. A lot of that is going to matter how your car is set up. Is it set up purposely to run on the bottle. Converter/Cam etc. or Is it just a baby shot every once in a while. But I don't see any reason why you shouldn't be able to slap a set of CNC ported l92s on there and get down. Just make sure you have the right parts in the head if you decide your going to start hosing her down good.

[Phish]

Right now i am running a 150 shot through it. I also have a 232/234 .595.598 @ 112 Cam. Brian Tooley dual valve springs and retainers and hardened pushrods. Converter is a TCI 3500 stall with an anti balooning plate.

Just unsure of the route to take. I know the ported L92 setup flows great and for the same price as buying an entire top end - i can get a set of AFR ported heads or Trick Flow ported heads to go with the Fast 78 i am running now. Didnt know if one would be a better route to take then the other.

[StreetSweeper]

Right now i am running a 150 shot through it. I also have a 232/234 .595.598 @ 112 Cam. Brian Tooley dual valve springs and retainers and hardened pushrods. Converter is a TCI 3500 stall with an anti balooning plate.

Just unsure of the route to take. I know the ported L92 setup flows great and for the same price as buying an entire top end - i can get a set of AFR ported heads or Trick Flow ported heads to go with the Fast 78 i am running now. Didnt know if one would be a better route to take then the other. Either way if you were to do a l92 set up with a fogger kit on about 200 or more Ryan Dao would never ever beat you in his life!
lol

[Sleepy]

Either way if you were to do a l92 set up with a fogger kit on about 200 or more Ryan Dao would never ever beat you in his life!
lol

I have no knowlege on the set up, but that actually made me laugh.

[StreetSweeper]

I have no knowlege on the set up, but that actually made me laugh.
Im just poking fun at Ryan BTW! lol

[Phish]

So your call would be the L92 setup. Sorry Ryan, sounds like i may be comin for ya next summer :-)

[AutoMods]

Im just poking fun at Ryan BTW! lol


i'll just wait until saturday. lots of new stuff with my setup. but if it runs good, i will run my mouth all winter

[StreetSweeper]

i'll just wait until saturday. lots of new stuff with my setup. but if it runs good, i will run my mouth all winter
I hope it runs great!

[Domestic Disturbance]

That fast 78 is going to hold you back if you start to go to the bigger intake ports. I know the trickflows and afrs also work very differently. Whichever route your best bet is a custom cam by someone like Ed Curtis or a reputatble vendor that is designed to match the heads/intake/etc. I think with that 4 inch bore you can dive into that ls3 head realm, which is based on l92 heads (square port). What sizes are you considering for runner cc? 215, 225? You really should get a bigger fast, and have it port matched; that 78 is a bottle neck.

But once you hits your 6's, whats in the future? Boost, more spray, stroker, next project?

[OldSkoolRCR]

i'll just wait until saturday. lots of new stuff with my setup. but if it runs good, i will run my mouth all winter

Why wait til all winter?...Ill start now come spring Ill drag your azz with a N/A set up. shit you can even have the hit!!!!

[Phish]

That fast 78 is going to hold you back if you start to go to the bigger intake ports. I know the trickflows and afrs also work very differently. Whichever route your best bet is a custom cam by someone like Ed Curtis or a reputatble vendor that is designed to match the heads/intake/etc. I think with that 4 inch bore you can dive into that ls3 head realm, which is based on l92 heads (square port). What sizes are you considering for runner cc? 215, 225? You really should get a bigger fast, and have it port matched; that 78 is a bottle neck.

But once you hits your 6's, whats in the future? Boost, more spray, stroker, next project?

I used to have a LS1 intake on the car. i got the Fast 78 for really cheap and i grabbed it because i could still use my plate kit for the nitrous. However i have no issue swappign otu the plate to a larger one if need be.

If i did go the the L92 route would a stock ported LS3 intake suffice or would i need to go with a fast 90/90 setup?

If i didnt go with the L93 top end, then i woudl probably be looking at 215 runners. I see me being satisfied with the 6's. Keeping it at a 150 and just enjoy the car. Maybe doing som other mods to it besides motor. Mainly just cleaning up a few things. Do a little on a second project maybe.

[StreetSweeper]

Yes what kitch said is correct. I guess I was under the impression you were running a car style efi intake on your car. Will deff need to figure out what is more important to you weather it be running on the bottle or what to determine how you set it up. A properly set up nitrous car will be a slouch on the motor and vise versa.

[StreetSweeper]

I used to have a LS1 intake on the car. i got the Fast 78 for really cheap and i grabbed it because i could still use my plate kit for the nitrous. However i have no issue swappign otu the plate to a larger one if need be.

If i did go the the L92 route would a stock ported LS3 intake suffice or would i need to go with a fast 90/90 setup?

If i didnt go with the L93 top end, then i woudl probably be looking at 215 runners. I see me being satisfied with the 6's. Keeping it at a 150 and just enjoy the car. Maybe doing som other mods to it besides motor. Mainly just cleaning up a few things. Do a little on a second project maybe. I myself am a fan of a carb style set up that is port matched to the heads. Plus nitrous daves custom puck system is really getting some positive feed back since they released it. Making good power and its hidden inside the intake. http://www.youtube.com/watch?v=1nyWoAR6Hfk Not to mention I think you can get the puck system door to door installed for like $300 bucks.

[JustaGT]

I myself am a fan of a carb style set up that is port matched to the heads. Plus nitrous daves custom puck system is really getting some positive feed back since they released it. Making good power and its hidden inside the intake. http://www.youtube.com/watch?v=1nyWoAR6Hfk Not to mention I think you can get the puck system door to door installed for like $300 bucks.
Looks exactly like Nitemare's nozzle from a few years ago..... Definitely a slick way of hiding stuff though, wish they were around when I had my nitrous setup.

[Phish]

An issue with the intake setup is also fitting it under a stock hood. Thats a big issue with me since noone really makes an aftermarket hood for the car and i dont want some giant scoop sticking up to cover an intake. Pretty srue a carb style intake will rise up to high. I beleive my only option based on height would be a 90/90 or the stock LS3 intake.

[AutoMods]

since you said you want to stick with the nitrous i won't mention that when you boost it and you can have subpar heads, mild cam and stock intake manifold and make more power without blowing up an unforged motor.

turbo setups do take a lot of work to build though. for some reason you don't see a lot of supercharged ls rx7's out there. i wish i could calculate how many bottles i would've burned through screwing around if i wasn't turbo and covert that to dollars to see how much that helps justify going boosted

[StreetSweeper]

since you said you want to stick with the nitrous i won't mention that when you boost it and you can have subpar heads, mild cam and stock intake manifold and make more power without blowing up an unforged motor.

turbo setups do take a lot of work to build though. for some reason you don't see a lot of supercharged ls rx7's out there. i wish i could calculate how many bottles i would've burned through screwing around if i wasn't turbo and covert that to dollars to see how much that helps justify going boosted LOL dude you go to the track once a year and show your face to the car public like 3 times a year total. where the f would you have been putting all that nitrous?

[Stutz]

The fast 78 has the same lower shell as the fast 90 so all you'd have to do is buy a fast 90 with a cracked lower and swap the top

[AutoMods]

LOL dude you go to the track once a year and show your face to the car public like 3 times a year total. where the f would you have been putting all that nitrous?

lol you make about 24 quarter mile passes down the strip each year (about 8 miles worth). i've put over 1000 miles on my car this year. the most its down at a time is usually a few weeks if i'm working on some decent changes. had it out every month the past year including nov, dec, jan, feb . this winter was pretty mild. during my forge motor build i was still running around with my old ls1.

i had nitrous on my rx7 before my turbo, my 10lb bottle didn't last long. what you end up doing with nitrous on the street is cruising around NA the whole time waiting for a race before you spray. where as a turbo or supercharged car you'll get into the boost all the time because its free.

[StreetSweeper]

lol you make about 24 quarter mile passes down the strip each year (about 8 miles worth). i've put over 1000 miles on my car this year. the most its down at a time is usually a few weeks if i'm working on some decent changes. had it out every month the past year including nov, dec, jan, feb . this winter was pretty mild. during my forge motor build i was still running around with my old ls1.

i had nitrous on my rx7 before my turbo, my 10lb bottle didn't last long. what you end up doing with nitrous on the street is cruising around NA the whole time waiting for a race before you spray. where as a turbo or supercharged car you'll get into the boost all the time because its free. None of that nonsense answered my question. You claimed that you spent more money in nitrous ten your entire turbo set up cost? Can you explain how? Did you spray from North Liberty to CR every time you maid the trip? You can say what ever you want but with the right set up his spray will wax your ass for life! On a second noteI hope your shit is on rails Saturday!

[StreetSweeper]

And what is wrong with cruising around on motor until you get a race? Most the lS nitrous motors still run 10s N/A, or at least the ones in this family do. Is that not fast enough to pick up U Line Boxes?

[StreetSweeper]

I'm not tying to start shit or cludder a thread I I just know damn well what a properly set up LSX nitrous set up would do in a RX7 and honestly would love to watch the battle of the LSxRX7s! And when I say I hope your shit fly's I really mean it. I want to see every ones shit run good and make improvements. It drives everyone to keep going faster.

[OldSkoolRCR]

I still say Ill drag your AZZ N/A with the new toy!!! Turbo BOY!

[Phish]

I thought about going turbo awhile ago and considered doing that over the winter. However i just cant brign myself to do it. I could understand if it was a T56 car or a 4L80 car or something of the sort. But i never really take the car out jut to drife around des moines. When its out its usually because other cars are out or i am giong out to run someone. Its plenty quick enough off the bottle to cruise around on. I dont know of a single place when out cruising that you could just roll into the throttle with the bottle on let alone a turbo and have it be safe when there are others around. All in all i can see the perks for both. To me, i turbo woudl be in order if i wsa jsust out driving the car and looking to beat up on shit. Nitrous is more in order when your out to purposly run someone and not jsut mess with every honda you roll up on when getting your starbucks and impressing the daycare kids.

That being said, the/any fast intake woudnt swap over from a cathedral port to a rectangle port would it? DOnt think they are universal or maybe i am crazy. Have not looked into it much. I just assumed the LS3 intake would suffice with the ported L92 heads.

The nrous shot i have at 150 so i dont have to keep going through short blocks. I am at the point where i want to keep it stock so if/when something does happen i can just throw another junk yard motor in it. If i were to build something to handle the nitrous, i think i would be at the point where i would not want to spray a ton through it because i woudl have so much money into it. Catch 22

[slow ride]

I'd just look for some nice ported 243/799's for the time being. That said, an aftermarket casting will have a thicker deck and provide slightly better results. Make sure the DCR is set up nice and tight, it will rip. The stock dished pistons on the lq4 are taking away some nice compression. Yes you need a new style fast 102 to get the ls3 port match. You would have to sell the fast you have now, but I do think the old fast will outflow a stock ls3 intake.


Just adding a nice set of heads and headers will make quite a difference for you I'm sure.

[Phish]

I'd just look for some nice ported 243/799's for the time being. That said, an aftermarket casting will have a thicker deck and provide slightly better results. Make sure the DCR is set up nice and tight, it will rip. The stock dished pistons on the lq4 are taking away some nice compression. Yes you need a new style fast 102 to get the ls3 port match. You would have to sell the fast you have now, but I do think the old fast will outflow a stock ls3 intake.


Just adding a nice set of heads and headers will make quite a difference for you I'm sure.


The dished pistons do tkae away some of my compression. However i coudlnt pass up the local short block for the money i got it for. Also, not sure how much i can take off the L92 heads to up the ratio and still be ok without dishing the pistons.


I totally agree that a set of headers and mild heads would make a world of difference. However if i am going to buy/install heads i would jsut like to buy the right set the first time and go with it. I will most likely do a stock LS3 intake for the time being to get the car back up and running for the spring time. Maybe upgrade the intake when the time comes down the road. What size opening is the stock LS3 intake have on it for a TB. Curious what to do for a nitrous plate and what TB woudl work well with that intake.

[RedRocketZ28]

LS3 intakes have a 90mm opening. I agree with Slow Ride if you plan on sticking with nitrous.

Turbo + 4L80e = tons of fun to drive. Only thing I would change on my car is a bigger turbo. I don't have to worry about nitrous running out at the track :). Plus, I like to drive mine whenever I get the chance. It's nice knowing you have 700 rwhp on tap when you want. I didn't build my car to race everyone and anyone. This is Iowa, we never do shit on the weekends and no one races anyone anyway.

At the end of the day, do what you think will make you happy.

[derek072887]

i wish i could calculate how many bottles I would've burned through screwing around if i wasn't turbo and covert that to dollars to see how much that helps justify going boosted


You claimed that you spent more money in nitrous then your entire turbo set up cost? Can you explain how?

I think he is just trying to convince Phish to consider going turbo to save money in the long run.....

[JustaGT]

Plus, I like to drive mine whenever I get the chance. It's nice knowing you have 700 rwhp on tap when you want. I didn't build my car to race everyone and anyone. This is Iowa, we never do shit on the weekends and no one races anyone anyway. At the end of the day, do what you think will make you happy.

This^^ Nitrous is definitely addicting, I had a lot of fun with my old GT on spray, even though it was a mere low 12 second car. But having >700rwhp whenever you want it without having to worry about running out of nitrous, heating up the botle etc. is a blast. Both definitely have their perks and I'm sure either way you go will be a fun ride, just depends on what you want to build the car for.

[Phish]

I have plunty of fun off the bottle on the street. Its pretty snappy with the auto, gears, and it being so light. I dont think the nitrous is the isssue that i am looking at here. Most of the time i jsut drive/run the car NA anyway.

I could always do something simple and just bolt up some PRC 2.5 5.3 heads to the setup i have now. Give me a little compression but loose out on the flow. Still think that would be the cheap way out though and i wouldnt see near the power gains as the other two options (Stock LS3 intake with ported L92 heads. or... Setup i have now with ported 243/799).

Where is the tradeoff with flow and compression? Is more flow way more important then compression, or woudl compression compensate for the lack of flow in a head that does not flow well? Chamber size has to come into the equasion somwhere.

[slow ride]

If you can find some good used CNC 243's I'd start with that. My old ones made a tick over 450whp using a 227 230 cam I came up(ls6 intake also). My old 383 made 482 whp with them and a 238 242 cam also with a ls6 intake. DCR was around 8.5 with flat top stock ls1 pistons. If you like it being crisp NA I wouldn't switch to the big cc ls3 ports unless you want to re cam it, etc.

[Phish]

Well, i figured i would just go along and see what i could find used and what popped up to help make my decision. Basically i found a good deal on a set of PRC 2.5 LS6 heads with 1200mi on them. AND a LS3 topend that contains a set of NEW stock heads at the same time. At first i was pretty set on the LS3 topend but now after talking to everyone on here i may be leaning tword the PRC heads. Anyone have a reason why i should choose one over the other? Both should make decent power i am sure. I think the PRC heads will keep it a little bit more responsive the the LS3 setup.

[slow ride]

Yes what you said plus you don't have to change intakes or fuel rails etc. Those prcs should have smaller chambers also. I'd mill them some if you have the piston to valve clearance to do so.

[AutoMods]

phish, was your car not running for the shootout?

[Phish]

I took it to eddyville the weekend before. I got a couple times there and could see what the car would do. I had every intention of going to the shootout but i couldnt track down a trailer, had empty nitrous bottle, and i broke a rear lug stud when swapping tires. Just didnt want to get up there, swap all my tires out, then get booted for the stud/not passing tech. Believe me though, once i got there i wanted my car to be there as well.

[Phish]

I finally pulled the trigger on the set of PRC 2.5 LS6 heads. They will most likely not go on untill winter. At the same time i am planning on doing some long tubes. Headers are extremely hard to find for a FC with an Auto trans however i believe a Kooks longtube for an SSR is extremely close and requires only slight modification. We shall see in due time. Thanks for the help guys. Maybe you will see it at BOTH shootouts next year. Since i hear there is going to be a spring and fall event ;-)

[AutoMods]

Since i hear there is going to be a spring and fall event ;-)

i'll make sure to bring up that idea next year. someone else might have to take charge of that one or it will have to be scaled down version maybe with no registration, cash awards instead of trophies.

[Phish]

I have a guy wanting to trade me a full LS3 topend with LS3 intake and 90 MM TB for my PRC 2.5 LS6 heads i just bought. Now i relaly do have the option of installing either top end. I am so back and forth on this. When i get peopels opinions it seems to be a pretty much 50/50 split on what to do with the RX7. I woudl do the LS3 topend, i am jsut afaid that it will make it less peppy down low off the bottle. Ugh. why are decisions likethis never simple.