250 WHP Supernatural 3.4 Build (Page 3/47)
pmbrunelle OCT 11, 06:55 PM

quote
Originally posted by La fiera:
I'm working on another crank and it will be much lighter and have much work,
it will be for this block but with a much higher HP goal, same thing; NA.



Isn't a good crankshaft, a good crankshaft, period?

What would you do for an NA engine's crankshaft that wouldn't also be good for an engine having a power-adder?
Blacktree OCT 11, 07:06 PM
It takes power to rev up an engine. The less mass the engine has to spin up, the more power can be delivered to the wheels.
La fiera OCT 11, 09:26 PM
I'm sorry for not being more clear PMBrunnelle, It's exactly what Blackthree described. Make it as light as possible
and being NA I can make it lighter rather than stronger. With that in mind the rods will be of a lighter material and longer
so I can get a shorter and lighter piston.
I don't know if I mentioned it yet but I'm working on a set of 3500 aluminium heads to complement that bottom end I just
mentioned and my goal for that set up is 300+ WHP.
But that is going to take a little bit of time.
First I want to use this engine on my Fiero and start doing Time Trials. I also want to make the car lighter to decrease
my power to weight ratio for the same reason, less weight = more usable power.

[This message has been edited by La fiera (edited 10-11-2017).]

Francis T OCT 12, 10:27 AM
I would suggest limiting your targeted peak power to around 5k - 5.5k RPM if you have an iron crankshaft, especially with a 3.4 - which is a stroked 2.8- too much reciprocating mass.

I got lucky - cost me $110- and brought one of the last -discontinued- Eagle STEEL crankshafts, else I would not have built my 2.8 for high RPM use.
BTW Venola makes good forged pistons that are priced good.
Francis T OCT 12, 05:38 PM

quote
Originally posted by Dennis LaGrua:

The goal of 250 RWHP from a 3.4L pr engine is a very aggressive one. I've built these engines and even
with a turbo have not reached this goal. You can improve the performance but the engine breathes poorly.
With loads of boost like 20 psi you might reach your goal but N/A I say no way.



We've -trueleo racing- have seen our customer's 2.8 engines with our headers and intake manifolds make more than 210HP and those were with stock or mild cams, stock heads, stock pistons, and stock ECU chips! BTW on the flow bench with our intake the 2.8 iron heads flowed enough CFM to support 300+ HP.

It will no-doubt take a lot of dyno time and probably, more than a few chip burns to get the tuning spot-on.
That said, I don't think his or my goal HP is impossible.

NOTE: I did not state the above to get new customers, whereas do to my medical issues and my son's very successful road racing program, we no longer make products for the 2.8 - 3.4 engines.

[This message has been edited by Francis T (edited 10-12-2017).]

Blacktree OCT 12, 05:50 PM
The 3.4 V6 bottom end is safe up to about 6500-7000 RPM (assuming it's in good condition). But anything beyond that is pushing your luck. Looks like Rei is going to improve the odds with lighter weight pistons and rods. That will push the RPM envelope a little higher.

Edit to add: for what it's worth, I'm going to be following in Rei's footsteps. Although I won't be taking the engine build quite as far as he is. But I also have a crazy intake manifold (from Ryan Falconer), and a "secret weapon" camshaft that Rei made for me. Plus the heads will be race ported. And I already have the Trueleo headers. Should make for a lively engine.

[This message has been edited by Blacktree (edited 10-12-2017).]

La fiera OCT 12, 06:32 PM
Well my redline is 7100RPM and my engine gets there pretty quick. But right now I have the rev limiter set up at 6800 for one reason,
When the engine gets to the rev limiter it cuts off fuel and spark (makes big BOOM and shoots flames!) and I can flat shift and even though I have flat shift capability in
the MegaSquirt I prefer the rev limiter method. The car just pulls like a freight train non stop in all the gears, I love my 4:10 gears with the welded diff!!

Mike, let mie know when you put that head, cam and intake combo. I can assist you with the tuning specially low to mid range with that cam, the stock timing table simply wont work. But don't worry we got you covered
Blacktree OCT 12, 06:51 PM
Awesome!

Edit to add: Can't you select what the ECM does to limit the revs? I know with my 7730 setup, I can have it retard the spark, cut the fuel, or both. Maybe there's a setting in the MegaSquirt for that?

(PS: I prefer to use the spark retard only, because that's easier on the engine)

[This message has been edited by Blacktree (edited 10-12-2017).]

La fiera OCT 12, 11:06 PM

quote
Originally posted by Blacktree:

Awesome!

Edit to add: Can't you select what the ECM does to limit the revs? I know with my 7730 setup, I can have it retard the spark, cut the fuel, or both. Maybe there's a setting in the MegaSquirt for that?

(PS: I prefer to use the spark retard only, because that's easier on the engine)




Yes I can. I'ts very adjustable. I can cut spark only, fuel only or both. But I think it makes that POP and make flames because the injectors are high in the
runners and even though it cuts the fuel and spark, there is some fuel on the walls of the manifold that when digested and gone through the hot exhaust pipes
raw that fuel is at the right temperature to ignite but it can't because there is no oxygen, once it gets to the tip of the exhaust it ignites and you can see the flames and
hear it.
I also have the high rpm decel (7100 to 4500) at -0.3 timing and enriched on purpose it makes loud poping sounds and the flames can be seen from miles!!!
Its awesome!!!
I have it like that so it can help with the scavenging of the exhaust thus increasing my intake draw in also. It works pretty good and keeps my throttle response sharp.
I have stainless steel racing valves designed for that torture.
One thing I tell you, you know when you see most of the cars when they hit full throttle and all you see is black smoke? You don't see that in mine, mine burns clean and the AFR's are right on target.
But don't worry, once you are ready just let me know and I'll make a special trip!

[This message has been edited by La fiera (edited 10-12-2017).]

Francis T OCT 13, 12:34 AM

quote
Originally posted by La fiera:

It makes loud poping sounds and the flames can be seen from miles!!!
Its awesome!!!
I have it like that so it can help with the scavenging of the exhaust thus increasing my intake draw in also. It works pretty good and keeps my throttle response sharp.
I have stainless steel racing valves designed for that torture.
One thing I tell you, you know when you see most of the cars when they hit full throttle and all you see is black smoke? You don't see that in mine, mine burns clean and the AFR's are right on target.
But don't worry, once you are ready just let me know and I'll make a special trip!



Yup unspent fuel meeting say a hot muffer would do that. Back in my younger, more devious days before the invention of steering wheel locks, we discovered that turning the ignition off for maybe 5 seconds on say a highway and then back on would produce a nice loud boom. It could and often did explode the muffler. Yeah, we used it to scare AHs on the highways. Lol it was especially effective when going through an underpass.
To avert such you may want to cut the fuel off too.