L98 heads/cam/intake build
#1
L98 heads/cam/intake build
Doing a build for a fellow member. About ready to start it up and make sure everything is running smoothly, and start the tuning process.
Car is a 60k mile L98 350.
So after much discussion, the owner decided on tpis big mouth base and runners, afr 180 heads, and lunati hot cam equivalent. Dyno don headers, march underdrive pulleys, smog/air delete. South bay 27lb injectors
Just about ready to start. Add plug wires and the air box.
Car is a 60k mile L98 350.
So after much discussion, the owner decided on tpis big mouth base and runners, afr 180 heads, and lunati hot cam equivalent. Dyno don headers, march underdrive pulleys, smog/air delete. South bay 27lb injectors
Just about ready to start. Add plug wires and the air box.
#2
Supreme Member
iTrader: (1)
Join Date: May 2015
Location: Temecula, CA
Posts: 1,149
Received 83 Likes
on
67 Posts
Car: 1989 Pontiac Formula 350
Engine: L98
Transmission: 700R4
Axle/Gears: BorgWarner 3.27 Posi
Re: L98 heads/cam/intake build
Excited to hear what kind of power it will put down. I'll be doing a similar build on my L98 shortly.
Trending Topics
#14
Re: L98 heads/cam/intake build
It could have...possibly.
All i did was adjust injector size, rework timing table, fan temps, max airflow limits (no changes to maf tables, just max allowable flow values vs rpm), and disable vats/egr/air etc. set desired idle speeds.
Thats basically it. From there you adjust the fueling, but its very well adaptive and why i like maf cars
All i did was adjust injector size, rework timing table, fan temps, max airflow limits (no changes to maf tables, just max allowable flow values vs rpm), and disable vats/egr/air etc. set desired idle speeds.
Thats basically it. From there you adjust the fueling, but its very well adaptive and why i like maf cars
#15
Re: L98 heads/cam/intake build
First drive, air fuels at minor throttle and cruising, its mid higher 13's:1. Idle shows leaner at 16:1 but thats likely some cam overlap.
Wot quick hit showed 12.0:1 so tune in factory trim with heads and cam is a bit rich. Just needs leaned out abit.
Going to fine tune rest of this week before putting it in closed loop. See how it does. Maybe try to get a dyno pull on it
Combo feels good. It has a magnaflow exhaust thats very quiet and likely very restrictive. But very torquey and well mannered
Wot quick hit showed 12.0:1 so tune in factory trim with heads and cam is a bit rich. Just needs leaned out abit.
Going to fine tune rest of this week before putting it in closed loop. See how it does. Maybe try to get a dyno pull on it
Combo feels good. It has a magnaflow exhaust thats very quiet and likely very restrictive. But very torquey and well mannered
#18
Re: L98 heads/cam/intake build
So did street tuning and got it in open loop dialed in. Wot was 12.9:1 or so. Stopped by the shop to give it a quick dyno pull and it made 272 whp and 353 wtq. Thought it make more hp but given the quiet magnaflow exhaust and stock maf with screens, it may pick up 20-25 whp. Hard to say. Cam has more split than i like but for 70$ clearance overstock sell its a nice cam. sounds nice.
Car is fun with 350 lbft from 2900-4100 rpm. 2800 stall matches well.
Car is fun with 350 lbft from 2900-4100 rpm. 2800 stall matches well.
The following users liked this post:
Richard Endress (07-05-2022)
The following users liked this post:
Richard Endress (07-05-2022)
#21
Re: L98 heads/cam/intake build
I honestly expected closer to 300 whp. But it may actually be near that if it was in 3rd. I kinda want to try again but i gotta fix the valve cover gaskets. They dont seem to be fitting well on these heads. But its the cork kind so i will go back to rubber
The following users liked this post:
Richard Endress (07-05-2022)
#22
Junior Member
Join Date: Oct 2000
Location: toledo,ohio
Posts: 40
Likes: 0
Received 2 Likes
on
2 Posts
Car: 1989
Engine: 5.7
Transmission: auto
Axle/Gears: 2.77
Re: L98 heads/cam/intake build
Thanks for the info looks like a good tpi cam with good tq down low enough. can we see a graph when it's all done. Dan
The following users liked this post:
Richard Endress (07-05-2022)
#23
Re: L98 heads/cam/intake build
Going to try descreen maf and redyno in proper gear this time. See what happens.
Current graph in 4th gear. I believe the little wiggle in the middle was converter locking up as i did not set the unlock prevention threshold high enough. Also saw a little knock there so i took 2 deg out. It should be fine once in 3rd gear. Will test later this week and try to get back in the dyno room
As you can see the torque "curve" is a big shelf of power
Current graph in 4th gear. I believe the little wiggle in the middle was converter locking up as i did not set the unlock prevention threshold high enough. Also saw a little knock there so i took 2 deg out. It should be fine once in 3rd gear. Will test later this week and try to get back in the dyno room
As you can see the torque "curve" is a big shelf of power
The following users liked this post:
Richard Endress (07-05-2022)
The following users liked this post:
Richard Endress (07-05-2022)
#28
Re: L98 heads/cam/intake build
No just big tubes. Big mouth base. Port matched to the head size. Which is just under 1205 port gaskets
Its pretty flat from 4200-4700. cam wants to go higher. Intake is holding that back some. Will try to take it to 5000 to see if it hangs on more. My guess it will
Bigger runners like these just boost power in the same rpm band as its tuned length. to pull more rpm they need to be even bigger but then you run into issues with radius of the bend. Have to sit the plenum up alot higher then
Its pretty flat from 4200-4700. cam wants to go higher. Intake is holding that back some. Will try to take it to 5000 to see if it hangs on more. My guess it will
Bigger runners like these just boost power in the same rpm band as its tuned length. to pull more rpm they need to be even bigger but then you run into issues with radius of the bend. Have to sit the plenum up alot higher then
The following users liked this post:
Richard Endress (07-05-2022)
#29
Member
iTrader: (2)
Join Date: May 2013
Location: Texas
Posts: 235
Likes: 0
Received 1 Like
on
1 Post
Car: 1989 GTA
Engine: LS coming soon
Transmission: 80E coming soon
Axle/Gears: S60/35 Spline/S-Trac/3.73
Re: L98 heads/cam/intake build
According to the graph, it's going to be a beast on the street! Hope the owner has at least 17x9's for better tire selection.
I too am baffled by the low rpm cut off! I thought you could get TPI motors pulling hard up to or past 5500? Guessing he doesn't want an HSR on it.
I too am baffled by the low rpm cut off! I thought you could get TPI motors pulling hard up to or past 5500? Guessing he doesn't want an HSR on it.
The following users liked this post:
Richard Endress (07-05-2022)
The following users liked this post:
Richard Endress (07-05-2022)
#32
Re: L98 heads/cam/intake build
Dyno'd again in 3rd gear to see if it changed power and gutted maf. No change lol did pick up more grams air flow in the log but made it slightly richer so had to remove some fuel
Runs and drives great, just figured it be nearer 300 hp than 272, but its a nice street car
Dyno'd to 4800 and trans shifted into od. Even when gear selector was in drive. Power was flat to 4800 and would go higher if trans was adjusted
Runs and drives great, just figured it be nearer 300 hp than 272, but its a nice street car
Dyno'd to 4800 and trans shifted into od. Even when gear selector was in drive. Power was flat to 4800 and would go higher if trans was adjusted
The following users liked this post:
Richard Endress (07-05-2022)
The following users liked this post:
Richard Endress (07-05-2022)
#34
Re: L98 heads/cam/intake build
Exhaust only L98 could be anywhere from 200-225, full bolt on tpi cars can see 230-240, it depends on condition of motor and the dyno.
So there is a decent gain in power with the heads cam stuff. More if it was allowed to rev higher with siamesed runner or stealth ram miniram deal
So there is a decent gain in power with the heads cam stuff. More if it was allowed to rev higher with siamesed runner or stealth ram miniram deal
The following users liked this post:
Richard Endress (07-05-2022)
#36
Supreme Member
iTrader: (2)
Join Date: Mar 2014
Location: South Ms
Posts: 4,422
Received 721 Likes
on
490 Posts
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: L98 heads/cam/intake build
Yea I thought a bone stock L98 was around 190 RWHP so 270 doesn't seem too bad! Bet its a hell of a street car. Id be very happy with it myself.
#37
Supreme Member
iTrader: (3)
Re: L98 heads/cam/intake build
How much more power do you think it would make if the pistons were swapped out for something that would push the compression to the 10.1 - 10.5 range?
This is a great project. I'm thinking about running a very similar set up in my car. Yeah, just have to get a 5,500rpm governor and that would fix the shifting problem. Those are still great numbers. Especially the torque, TPI's claim to fame lol.
This is a great project. I'm thinking about running a very similar set up in my car. Yeah, just have to get a 5,500rpm governor and that would fix the shifting problem. Those are still great numbers. Especially the torque, TPI's claim to fame lol.
#38
Re: L98 heads/cam/intake build
Not a whole lot more maybe 15-20 hp. The pistons are flat tops with a big channel relief for valves. Different than my old 89 which had slight dish
It has a 2800 stall, i think a yank or precision industries. Not sure but its perfect for this setup. Well over 300 ftlbs from 2500-4700
It has a 2800 stall, i think a yank or precision industries. Not sure but its perfect for this setup. Well over 300 ftlbs from 2500-4700
#40
Supreme Member
iTrader: (3)
Re: L98 heads/cam/intake build
Not a whole lot more maybe 15-20 hp. The pistons are flat tops with a big channel relief for valves. Different than my old 89 which had slight dish
It has a 2800 stall, i think a yank or precision industries. Not sure but its perfect for this setup. Well over 300 ftlbs from 2500-4700
It has a 2800 stall, i think a yank or precision industries. Not sure but its perfect for this setup. Well over 300 ftlbs from 2500-4700
Thread
Thread Starter
Forum
Replies
Last Post
Aaron's 87
Aftermarket Product Review
4
11-04-2000 09:32 AM