ECU Retune ceiling

[spoiledred94]

I have a few true performance mods. FDR change, 1.8 roller rockers, CAI etc. I ordered a new EPROM burn, which is in progress. I don't really know what changes to ask for. The pre burn info sheet was easy enough to fill out, but lacks depth. What can I change for the best performance (track ONLY)? Timing, shift points etc are something I don't know how to set.

[willwren]

You're on un-tested ground. Nobody has ever really bothered to mess with the L27 before, and it isn't likely in the future.

[95naSTA]

You'll need a wideband to really dial in your WOT a/f. WOT O2 voltage will get you close but you'll never know for sure.
Then you can (hopefully continue to) moniter knock and increase timing from there.
You're not going to want to raise the shift points much if at all on an L27.

[willwren]

And even if you did, you'd need a dyno run or two to determine them.

And then you'd only be netting yourself another 5 or 10hp at best, and you'd still be running in the 16's (or whatever it's running these days). It's an awful lot of bother for wasted money and time and very little (if any) gain. Your car only had 170hp to begin with, and you're still well under 200 now (probably about 180 at best). That equates to about 144 horsepower to the wheels at best.

Don't waste your money on another tune. Go L67 first. That's the best upgrade for the money.

[01bonneSC]

I would just buy a camaro or mustang.

[95naSTA]

People have done more with less factory hp. I remember Don talking about some ballsy LN3s/L27s.

Here's a 265hp LN3 Fiero:
http://www.fiero.nl/forum/Archives/Arch ... 56533.html

[willwren]

But we're talking about a 180hp L27 here. Not a performance-built machine.

[mhfromphila]

Spoiledred94 I would not do the retune yet. Go to the JY get a L27 LIM and do a Port and polish. If you have the time and the cash then get a set of JY S1 heads (93 and up so your rocker bolts fit) port and polish the heads.I don't know if you can get 93 octane on the west coast but if you can ,than shave your heads a little.I know you have some exhaust work ,but is the pipe size 2.25 or 2.50? 2.50 is the max. for a L27. Have you check your exhaust manifolds for cracks? After all this work then do the retune. But you will be doing a lot of work and $$$ for a car that may do 15.8 -15.6 on a good day.

[spoiledred94]

I am pretty happy you guys took the time (well except Jake )

The l27 car may not be a great performance platform, but it is a good car to learn with.

95naSTA (couldn't find your name in the "first name only" thread)

You seem to know what you're talking about. Though I don't. What is a WOT O2 voltage? I know my TPS needs adjustment, but I don't know what a wideband is unless it's a type of scanner. I have a scanner. Is there more than 1 kind for my car?

Will,

I'll keep this short. IDK jack about HP gain #'s. The CAI is billed as 20ish and the rollers are about the same. The exhaust work is an HP increase I think. I'd like to drive a more muscly version of this setup just to get an idea what 200+ HP is like.

mhfromphila (couldn't find your name on the list either)

My pipes are 2.5" ID so I am at the limit now

The p&p job sounds good for a winter project I think. Can I get the JY parts and work em over over the winter and then do install later so I can drive my car?

Great suggestions for HP gains. The timing question though... This ECU will not be driven on the street too much. I have other more applicable versions for that. The bill is paid. It just has to be burned by Ryan. If nothing else I can nix the fuel cutoff at 108 mph

Kris

EDIT:

I looked around an found a couple demo vids on Porting and Polishing and it didn't look too bad. My priority is the burn right now then the holidays. Ryan said he could "optimize" for a general performance increase. Can't do much at all with the few real mods I have.

[willwren]

Your intake is 5hp at best, just like mine and everyone else's. The intake does less on the L27 than any other motor, as the other motors all flow more than the L27. The rockers are 20hp on an L67, not on an L27. They gained you 5-10hp. The exhaust did nothing for you, because you're not outflowing what you had. You're flowing less than half through the motor than quite a few L67's here.

P/P an L27 LIM is a waste of time. It's a good casting to begin with, just like the Series 1 L67 LIM. It's the L36 that has the problem. There's maybe 1-2 hp to be gained there. Polishing the heads will be a waste of time IMO, as you're not flowing anywhere near the flow limit of the stock ports.

You have to increase FLOW through the motor to have any reason to increase port sizes on any component. The only way to increase how much flows is through a power-adder or valvetrain mods.


You really need to come to terms with the fact that you're not going to get any appreciable horsepower gain with an L27 until you throw a power-adder on there. Be happy with the bulletproof design of the motor, and the natural low-end torque. The design of the motor is great, but it wasn't meant to flow, and wasn't designed as a high rpm horsepower motor at all. It seems to me that you're expecting it to perform and react to mods like an L36, and that will never happen. The L36 was a near-total redesign for horsepower at higher rpm's.

[mhfromphila]

I'm with Willwren on this. I don't think is going to give you looking for, time $$$,and work involved. As far as tuning search is were to start. KR is the enemy check for it with your scanner.

[Jrs3800]

The 1995 L27 is the only odd ball out of all the L27's produced... The Buick LeSabre, the Olds Chevy and Pontiac vans for 95 as well as the Series I Supercharged for 95 are odd in that they use some of the series II parts...

But in the end these engine flow no better than any L27 produced... The 95's if it has a series II oil pan( also meaning it has a series II Crank ) will spin through the revs faster and the crank lost weight( again 95 Only )....

Can an L27 be made to make power... Yes... But it would take a lot of time and money.. If I do anything with my 95 L27 in the shed, it will get the proper pistons for boost, as well as the SC rods and have an M62 parked on top with the correct tune.....

At most, you are making 180-190 HP... Keep in mind the series II was designed to be more of a midrange performer with a decent top end.. And on its worst day in an H body it would make 205 Hp...

I understand what you are trying and wanting to do, but see it mostly as a waste of $$$.... And I am not sure how your car is running...

A local here has made several track runs with his Buick Le Sabre... 1993 with the L27, a ported lower( yes I did that for him ) and the ports on the heads are kissed... as well we installed a 1997 4T60E with the 3.06 gear ratio.... His originally was a 2.84 ratio... We found the correct 1993 Mem Cal with the 3.06 ratio from a 1993 Bonneville...

On a stock intake, stock injectors, Stock rockers, 100% stock exhaust... He was doing 16.1 - 16.3... His launches were a little brutal... I think he could have pulled a 15.9-16.0 with a good launch... If we installed the 1.8 rockers on his car I would bet on 15.6-15.8 with a good launch...

The 1997 trans is 100% stock and have never been altered with the exception of me changing the internal harness so that it would function with the 93's electrical... Porting of the lower and kissed heads only happened due to the intake gaskets needing replacement..

Now, short of an L67 myself and the owner both know his car will not get much faster if any at all... We would be extremely lucky to squeek a 15.8 out of the car in average conditions...

[01bonneSC]

I am pretty happy you guys took the time (well except Jake )

Just trying to help ya go fast, which is what you seem like you want to do, for cheap. Plain and simple.

[willwren]

Your advice in this topic is more than practical. Far more practical than what he thinks he can do with his L27.

[00Beast]

For reference, a Wide-band is an O2 sensor that reads to a gauge your true fuel ratio. It's used for tuning.

[01bonneSC]

For reference, a Wide-band is an O2 sensor that reads to a gauge your true fuel ratio. It's used for tuning.

Also read as "not cheap". They are pretty darn pricey, so if you can borrow one or buy a whole kit(sensor, wiring, gauge) it would be the way to go.

[spoiledred94]

I was aware the SP chip would do little to increase my HP. I was looking at it to finish my performance enhancements. It's not all that much. But you have given me ideas. The P&P, and Series II parts swap would be something I would like to do. But, it seems what I really should do is do all of this to a Series II L67. Again I understand that this would be a huge amount of work and cost a lot for little gain. I just don't want out of this car I don't think I have to worry about KR with my car the way it is do I? P&Ping a set of JY heads over the winter would be a good way to learn how to P&P. I can check ref but would a valve job be something to tackle while doing the heads? New car? Not going to happen this winter.

[95naSTA]

I think Don laid it out for you pretty good.

Do you want to go faster than mid/high 15s? If so, stop messing with a rockered L27.

Do you want to spend a ton of time and money get as close as you can to 14s n/a L27?
You need to send the heads out to someone that actually knows what they're doing, mill the crap out of them, mill the LIM, big cam, long tubes, etc.

And if you don't know what any of that means, don't ask, find answers through research.

I didn't answer your question before because it would have taken 2 seconds to google search wideband or WOT O2.

[spoiledred94]

Point made, but in my defense, this thread has gotten way off topic. I was hoping to pick up some help on the Sinister burn. No doubt I am failing to ask myself those important questions. Like what do I want from this car? Would I be better off sitting tight until I can buy a Series two SC? Do I want to kick down HARD (for me) cash to get a crank and cams made? I don't want to give up the ghost on greater performance for my L27, but honestly 5 hp gains ea for 3 or 4 mods for thousands of dollars is beyond me. As Will made me aware my car cannot handle a lot more hp without a bottom end beef up. I don't know what you guys meant by sharing all the big kick mods. I'm happy you gave me a peek at them though.

[Jrs3800]

At most with your current mods, I would raise the 1-2 and 2-3 shifts roughly 200 Rpms( no reason to go any further ), if you are KR free and you are positive of this...!!!!! You could add 1-2 degrees of timing... Alter you fan turn on to come on at say 200F and off at 190F( That is if you are using a 180 T stat ).... Beyond that I don't know what you could adjust...