Confused about mods effecting stock bin

[BigBanks78]

1990 2.3l quad 4 Dohc 16 valve 5 speed in a fiero

Is there anyone out there that can give me an idea of why the stock ve table is way rich. The mods I did were port matching exhaust to the stock 4-2-1 header, (exhaust ports were very necked down!!!) made them more aerodynamic too. Only cleaned up intake ports.

I understand and header will scavenge and it will be flowing a lot more air due to larger ports but having a little trouble under standing what these changes did to the engine characteristics. The ve table looks completely different! And wondering what other parameters are going to b way the heck off. Raising injector pw seems to do good but lowering accel enrich seems to do good too? Will opening exhaust lower need for accel and power enrichment.

Basicly asking how a pro with a lot of experience would start this tune and what they might expect the engine to do or how it changed?

Thank you for your help!!!

[steveo]

lets see your old vs new ve table

[1project2many]

Assuming you didn't forget a vacuum line to the pressure regulator, is there any chance you inadvertently reduced airflow into or out of the head?

[BigBanks78]

I get some up in a bit. I have changed some others I'll put up too.

[BigBanks78]

I got a microscope on this thing and not finding anything mechanical. I can't see anything, idles at 30+ kpa but in origanal car intake was behind radiator cooling fan so MAT was probly always 150+f now it's in the back of a fiero getting close to outside temps, intake ran out rear fender. I could have screwed the ports up, the way they flow?!? But don't think so???
hadnt had much time to get on here but I'll show u what I think is weird I a couple hours

[BigBanks78]

The blue lines are the completely stock bin file. I think mat is measured in Fahrenheit not Celcius though! The advance in mat timing makes Blm go as much as 4 blocks lean where stock Blm goes as much as 15 blocks rich. And the change starts to happen at 75-78f.

[BigBanks78]

My tables r not perfect but close except 2000-2200rpm 30-50 kpa is still 121 Blm and 2400-3000rpm 30-50kpa is 118-123blm. Upper rpm 4000-5000 shoul b fairly close but not sure above that.

[Xnke]

Opening up the exhaust ports was probably a bad move. If you've really opened up the port and smoothed things out and gain a lot of low-lift flow, you will get a lot of exhaust gas reversion into the chamber, which will mean the intake can't pull enough air in to burn the intake fuel charge.

That'll result in the stock VE tables being extremely rich.

[BigBanks78]

I am working with a low out put engine, big valve head. I ported the exhaust like I did because the high output head has much larger exhaust ports.
If there is reversion and the intake valve are not the restriction, it can be fixed by opening the intake manifold runners or air intake system like filter, intake tube or larger throttle body right ? I can weld aluminum and fabricate whatever so I can make a bug tube intake manifold.

I am learning how to tune with this set up, but, I will b supercharging this engine, so I probly just need to figure out which compressor I'm gonna use and do it right? Sounds that way to me anyway. I guess I wanted to get the hang of it first. I have a supercharger off a 3.8l Buick, but also have a supercharger off a c230 Mercedes's that only suppose to work at low speeds so that will be paired with a turbocharger if I use it.

I had this thing running great end of last summer (tuned it in 100degree weather) but cold weather moved in and messed with tune or I lost a file somehow. It was fast enough to scare me a lil so I know it has power and that's why I'm so frustrated.

[BigBanks78]

Sorry I also added 10 degrees timing on whole table and a couple more degrees in high kpa... I haven't boosted yet because I'm driving it to work and back until I get all the boost parts together, I cobble all the parts I need before I start something.
Anyway thanks for the info, I will be checking stuff again with exhaust reversion in mind! :-)

[Xnke]

Which Mercedes unit? Do you have photographs of each blower?

They're both Eatons, one is probably an M62 (but could be an M45) and would be basically the same as the Cobalt SS unit when fitted to your 2.4L quad four. It would be the better fit, but you would need to either lock the pulley on all the time or change it for a non-clutched one. I think you can pick up the non-clutched pulleys on Ebay now, actually.

The 3.8L is *probably* an M90, and would be somewhat laggy when driven to the same boost pressure, but that may be acceptable if you are street driving, as it returns better fuel economy on the highway and at low throttle positions.

Supercharging an engine must be done as a *SYSTEM* not as a collection of parts. It's taken me 6 months to assemble my supercharged V6 for the truck and it's not in the frame yet.

Just as suggestion, but DO NOT modify the car you rely on for daily transport to your day job...it WILL bite you in the ass every chance it can until you're 90% sure it's done and perfect, and most employers aren't sympathetic to the "motoring enthusiast"...

If you're planning to boost a quad four, the first thing to do is a plan. Your plan seems to change almost daily, from reading your posts. If you'd like, PM me here and I'll help you lay out a plan that will be workable, tailored to your goals and then you can start a thread on what you are actually going to be doing and how you plan to do it. It will be a great help to the guys here who are trying to help you out, and will help things go a LOT smoother!

Anyway, back to your current problem.

Why did you add 10 degrees of timing to the WHOLE table??? That's a LOT of timing in some areas, and can really kill your torque output, if it isn't detonating away your pistons! Too much timing REDUCES torque by making the piston work to come up the bore. I'd pull that 10 degrees right back out again. If you have not modified the combustion chambers, there is no need to alter the factory timing table at this stage of the game.

If we suspect reversion (I do) then step one is to run the engine around the block a few times at varying RPMs, then park it, and pull the intake manifold. Check your ports for black soot blown up into them, measure how far into the manifold it goes, and then scrub them till they are clean aluminum, ports and intake manifold. You should see very little soot-almost none-if you are not experiencing reversion effects. I would not expect to see soot past the intake manifold flange if there is no reversion *problem*, but you might see some soot in the valve bowl and the deeper parts of the intake port, depending on how hot the factory cams are. Now that you know if you still suspect reversion, you can make another run, through the whole RPM range at WOT (might need to do that in a low gear going uphill to load the engine enough not to go straight to jail....) and check your ports again for soot, take measurments, etc and compare them.

Next, measure the intake port diameter, cross sectional area, and measure where in the port the minimum cross section is at-the tightest point in the port. Then, you need to know the valve diameter, and the inside diameter of the valve seat and the valve bowl itself. You need the same data for the exhaust port-both the stock port and your newly modified port. Also, some photos will be handy in figuring out if you've killed exhaust flow or if you've improved it with your porting. Most of the time, your exhaust port exit should be *smaller* than the header flange hole, you want a small step on the exit of the port to help kill reversion effects.

If you've improved your exhaust, you may need a well-matched header to take advantage of it. Let's get you going in the right direction (where the engine wants MORE fuel, not less!) and then take it from there.

[Xnke]

Also, are you absolutely certain you got your camshaft timing exactly in the factory position? That could make exactly the same kind of difference!

[BigBanks78]

Very interesting!!! Ok on porting, I left exhaust ports maybe 3/16ths all the way around smaller than header, read polishing ports creates heat so went over with sand cloth rolls after porting. I have pics before and after I will find. I will be indexing cams soon, I have to drill a hole in cam covers to do so though but I have extras :-) My dad built a Oldsmobile 403 some yrs ago and found the stock roller cam from a late 80's 307 to be 10 degrees retarded [center line I think] past what cams are usually, he said for passive egr. He took the 10 degrees out and started over and he said that fixed what ever problem he was having. So that's where indexing the cams idea came from, after I read ur post about reversion. Hopefully that's it because this engine, 1990 2.3l actual Quad-4, has no egr valve but has all kinds of egr parameters in bin??weird!!!!

I added 10 on timing table because there was no power and no knock, I added little more in places that r dipping in ve. Adding more timing in 2000-2200rpm 40-60kpa really perks the engine up. I have set power enrich timing back to stock because just what u said, sparking before piston comes up, feels like deceleration when pe comes in.

I usually spend a lot of time figuring out what I'm gonna do to a car, I just grab stuff I may need if it's cheap. I have the whole 99 c230 car, cost me $150 maybe. Got 3.8 supercharger for less than $50 at a salvage yard new year sale.
I have 5 cars, I know all about working on ur daily driver :-) I switch back and forth but my regal gets 6 miles or so to a gallon so don't drive it much :-))

Anyway runnin out of time I will get those pics up and tell u more in a lil bit. Thanks bro

[BigBanks78]

Header is same size as gasket. I'm going to run a bore scope down intake and try running with out filter and intake tube to see if there is a restriction some where, hopefully I didn't leave a rag in it.......
Oh and I'm all over the place because this thing is confusing the crap out of me, I don't know what more than half the parameters do (most don't do what I think they should) and I apparently don't know the correct terminology to ask a question that relates to what I'm experiencing with car :-) plus wife and kids run me ragged. And my computer skills suck! I asked about how to make a spreadsheet for the xdf I'm using, someone told he how I just haven't had time to sit and relearn xl.

Im usually pretty good at collecting parts for my projects but it take me couple yrs some times to get them all. I had my fiero for at least 7 yrs before I started on it, bought a grand am for engine and stuff, striped what I thought I needed and had that stuff for 3yrs, munchie 5 speed is brand new, traded a Saginaw for it several yrs ago and have been getting little interior and body stuff along the way. I'll read urs again and answer what I missed

[BigBanks78]

I won't be supercharging anytime soon, I would like to learn how to tune with this the way it is (so I can put mpfi on 455 in my regal) if I melt pistons in this 4cyl it's not a big deal I have another in storage building, and to drive something that gets fairly good gas mileage (with as much power I can get) while I get stuff for regal. I didn't think tuning would make me want to shoot myself in the face :-)