BigRedCoupe

Hello Corvette Forum,

I've been big on the Subaru world for the past 10 years. 4 Subarus total right now, modded out 2002 WRX ~300hp, Classic RS Impreza, Turbo Outback Wagon (Sunday sled) and Classic Forester. I am looking to trade/sell 1 or more of the Subarus for a 92+ Corvette. I like the LT1 (optispark and all) but what I really care about the the ECU. Subaru since 2002 has had an easily open-source modified Turbo ECUs, a $10 cable and free software and you can modify the whole ECU, not just spark timing and AFR but things like fan temp on/off, fuel pump duty, two-stage rev limiter and boatloads more. Being able to monitor and change the ECU tables mean a lot to me. Is this possible as DIY flash and cable or do they all need closed source programmed/burned chip PROM? I know being OBDI limits it heavily.
The only other things in the c4 I care about is the J55 HD brake package and z51/z52 suspension. The FX3 suspension would be nice but I doubt I'll find it. The only thing I think I'd like to do it replace all the bushings with poly and the rear mono-leaf. I know they will squeak, I'll deal with it. I know most Corvettes have issue with cooling due to limited airflow at standstill so an all alloy radiator and oil cooler would be added (any other reason editable ECUs are nice is to set the fan trigger temps and 1 or 2 fans on/off).
Are there stock steering fluid coolers?
99% of the C4 are auto so 6 speeds are not going to be happening and I am not interested in the earlier Doug-Nash 4+3.
Let me know what you think. Will I like the tail happy RWD Corvette after the "point-and-shoot" AWD ease of control in my WRX?

gilhuly

Hello and welcome to the forum!

for informed answers check out the C4 tech section
https://www.corvetteforum.com/forums...erformance-48/

FX VETTE

Welcome to the CF!

Vetteman Jack

Moving this to C4 Tech.

fredk

I have a story for you. Not a track story but a 1/4 mile. My son and I were having fun at a test and tune day. A young guy in a Sti asked me to race him. at the time I just had headers and gears. I beat him 5 times in a row and he left shaking his head. Don't underestimate our old girls.

Tom400CFI

You can buy hardware to program and burn your own chips. Others can give you the details, as I'm not well versed in that area.


Bushing shouldn't squeak if they're lubed properly, but with stiffer bushings the suspension is a "binding" design. Rod ends are ideal and "Banski" makes kits for that.



The Corvette cooling system works great...when properly maintained. It gets the "rep" of having cooling system issues from three sources;
1. the cooling fans don't turn on until ~230*F, and that scares people...they aren't used to or comfortable with it.
2. the coolant gauge LOOKS like it's almost reading 260*F, when the fans come on at ~230. That scares people...they aren't used to or comfortable with it.
3. People don't maintain their cooling system and cooling performance suffers. Then you get threads about "these cars overheat easily".

If you get an LT1 car, do some proper PM and set the fans to come on at ~210*F, you should be great. As an example, I've autocrossed my LT1 in temps approaching 100*F..with "dual drivers" so it got beat with no breaks. I ran the AC and the temps never went above ~205 or so.


Yes. LT1 cars have power steering cooler, stock.



IDk how fun it would be with an auto...*I* would hold out for a stick car for sure. More reliable, more fun, more gear ratios and faster. The C4 is a fun car to drive but I can't say if you'll like it compared to a WRX...that is a personal thing.


.

bjankuski

The 1992 car does use a flash chip but it is possible to buy the equipment needed burn your own chips and tune the cars. A source to do this is Moates. He sells all the equipment and maybe even the TunerPro software. Another software and equipment provider is CATS, they have an LT1 package that provides everything you need.

If you want to do real time tuning and not burn a chip Moates has a few options that allow you to use a laptop to make changes on the fly and then burn a chip when you are all done. Some guys never burn a chip and run the car all the time on the emulator.

DGXR

6-speed cars are more expensive. But if you have good reasons to want/need a 6-speed, the higher price is definitely worth it, in my opinion. The ZF S6-40 is a tough transmission.

Going from turbo AWD to torquey RWD car, obviously your driving style will require adjustment. But after you have adjusted, I think you will find it just as fun and actually more rewarding

Pwnage1337

more info on the turbo outback?

Sounds fun... Lol

BigRedCoupe

2005 Subaru Outback 2.5XT Limited. Loaded out, winter package (heated leather, auto heated mirrors, LSD) , 5-speed auto with steering wheel sport-shift. It's all stock, clean and is a dream but I don't need 5 cars right now.

BigRedCoupe

Thanks for the detailed reply. Sounds like the cooling issue is much like the Optispark; poor maintenance and neglect are the root cause and not only the component design (but that was changed with the drain vents too).
Did you get the ECU flashed to lower the fan-on to 210F?
As for the bushings, which ends are binding? My understanding is that the rear is Independent leaf sprung and the front is double wishbone AKA a parallel linkage. Rod ends and heim-joints links are great for sure but over-kill for a road car. I just like using bushing to eliminate lost motion as a simple way to clean up the chassis and use the power you make more efficiently.

BigRedCoupe

Thanks for this great info about ECU tuning. Have you used either method?

QCVette

Welcome to the forum.

The '93 and older use a prom that your burn separately and then swap into the car's ECU.

The '94 and '95 can be tuned by flashing the ECU without changing any prom. Try checking Moates.net for some cables and links to software and files.

The '96 is OBD2 and also is flashable, but I am not sure that many (or any) good DIY tunes are available. (Although you can swap to a '94 or '95 ECU.

I don't like the FX3 or F45 adjustable suspensions because of the expense of the shocks where there are some very good choices for non adjustables (I like Bilstein Z51 shocks) that I think may perform better.

Springs and sways can be swapped. See the following link for listings of the stock setups.
http://www.corvetteactioncenter.com/...usp_chart.html

All of the '95 and '96 both have the J55 brakes. '94 and older it was optional.

Good luck and have fun.

hcbph

I'm going to make the same suggestion I've made before. If you get a Vette, drive it a while before making changes. Get to know the car, what's good about it and what's not. Then make plans to make whatever changes you deem appropriate. Myself, I took over 2 years to decide that my car accelerated and braked just fine for what I wanted. What I didn't care for was the way it handled those curvy, windy back roads so that's where I put my attention. Once I got that taken care of it was a whole lot better than most and a joy to ride in those situations.

Your usage will dictate what you want to do about it.

Tom400CFI

No, I am comfortable with the temps...and if, for what ever reason, I don't like it (like the autorx race for example), I just turn on the AC (which turns the fan on).



That makes sense for your intended purpose. But so you know, the trailing arms get twisted by camber change of the knuckle...so there is binding there. The lower lateral link gets moved for/aft at the knuckle end by the short trailing arms, so there is a little there too. Not terrible though...not like a 4 link rear in a domestic solid axle car.

bjankuski

I have used both and either works fine, I prefer CATS (Tunercat) but that is just me. Most people use Tunerpro since it is cheaper and has a built in scanner.

BigRedCoupe

Thanks, these are all good points. I'd be happy to get it to be equal to show room numbers, after all the first c4s are 33+ years old now abd rust never sleeps...Seems like a long shot but maybe I can get my *** in gear to sell or trade some of these Subaru.

BigRedCoupe

From that matric it looks like I want the Z07 or Z51 RPO code chassis. Good to know.

hcbph

One nice thing about Vettes is the lack of sheet metal bodies to reduce rust exposure. The bodies aren't perfect as there can be cracks or damage over time but like everything else it's fixable.

Mechanics are Chevy so there are many options there. Rebuilding or replacing mechanicals are available. OEM bushings were rubber while replacements are only available in poly. An upgrade I did to mine was the Banski suspension kit is well worth the consideration if that's where your interest is.

IMO usual areas that need to be attended to in many cases are the paint (including clearcoat), electronics and abs. Some of those parts can be difficult to find but most can be found somewhere if needed. Paint can be redone but it can cost more than many of the cars are worth unless you can do it yourself.

C4's are like any other car of this era in some respects. The newest is over 20 yrs old and the old is over 30. Things can age out just due to age in many cases. IMO it's better to find a car that has been driven a few thousand miles each year than a garage queen that's never been moved. It keeps seals etc tight and parts lubricated if they're driven on a regular basis.

If you find a car, you can always come back here for analysis and opinions on possible purchases. It's also beneficial to have a prepurchase examination done of a car to avoid those with more hidden issues.

Good luck, hope it all works out for you.