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.

 

Excited to hear what kind of power it will put down. I'll be doing a similar build on my L98 shortly.

 

Stock tpis big mouth, already port matched to the heads. Plenum matched to runner and 52mm tb

 

What gears does it have I it?

 

3.27

 

interesting

 

It runs lol base tune and needs iac set, est connected, and start tuning

 

sounds good , cant wait to drive it ..

 

very nice. I want to build the same kind of motor for my car. How much compression is it running? Any guess on the power and torque numbers?

 

It should be mid 9's to 1 comp. i got an idea for power but want to wait til i get some logs in to see

 

I have that cam and am on the fence if I want to go with it. where is it installed straight up? Dan

 

I believe cam card calls for 108 icl. Thats "dot to dot" straight up on the timing set. I degree all cams to double check events.

Cam sounds good and should be a killer street deal

 

So that's a cammed MAF motor and it started and ran with no tuning? That's awesome

 

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

 

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

 

Most will, MAP cars are harder to sneak by

 

Whats up with the IROC ray?

 

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.

 

Lol just realized car was in 4th gear on dyno. Ran to 150 mph. Car is a 3.27 gear not 2.77 so numbers are alittle low than what they could be. Makes sense now

 

I'm glad to see those numbers. I'm looking to build a 355 small block for my car with similar components.

 

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

 

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

 

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

 

What are the specs on the cam?

 

https://www.thirdgen.org/forums/tech...ubstitute.html

 

The cam card says 219/228 but its basically a hot cam with slightly faster lobes. Running with a 1.6 rocker for .536" lift.

Hp carries well but mainly that torque curve carries from 2800 to 4200 extremely strong

 

A little disappointing to me the intake still peaks power at 4500. I take it the runners aren't siamesed at all? I bet the average numbers are pretty good though.

 

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

 

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.

 

You can but you need port volume and or siamesed runners

This is only a 180 cc head. The big rpm tpi setups are welded up bases on 1205-1206 ports. Custom runners etc

 

How is this project going? I'm very interested in how it drives.

 

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

 

272 doesn't seem too bad.. How much would it dyno stock typically?

 

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

 

thanks for the info umm what about the converter is it stock?

 

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.

 

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.

 

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

 

sub-

 

Still would be a great combo to drive on the street. Cool, I get heads and cam and won't worry about the short block too much.

 

If you did a bigger cam and 195 heads, i would prefer more compression. 10-10.5:1 easily with a 224+ deg cam

This one is 219/228 and would like more intake manifold to rev higher but overall its a good driver

 

got the car back from justin yesterday and it runs awesome. great job justin !!