DIY LS3 swap kit - long term testing & improvements

[pillbox]

Congratulations on your success! Looking forward to a complete BOM and CAD package.

[TRS]

Fun Fact comming to my mind just this moment:

Just in case I decide to build a home once more and just in case I also decide to get 5 bags of concrete from home depot with the GT, 40kg each, and I carry them in the trunk I would archive same total weight and same bias as a Corvette C7 GrandSport. Just hypothtical I mean...

[Irace86.2.0]

That sounds good and bad when you say it like that.

[TRS]

I dont see that much bad news there. Sure, 50/50 is optimal they say. But I think every race engineer would love to accept a free 15% weight reduction, even if its concentrated on one end of the vehicle.

Adopted there are two identical vehicles and the weight of one of them gets reduced on the rear end by 15%, it is clear that the other is the one with the better balanced handling. But would you even say that the one without reduction is also the faster one on the track? Sure, depends on the track layout (or the type of competition), but in most cases I would say the lighter one should make the race.

To be clear with that, I dont want to make a statement that a swaped 86 is faster/better/whatever compared to C7 GS. There are many many more differences between those two Cars than only weight and bias. I wouldnt go out on a limb and make such a statememt.

This beeing said, I realy like the handling, also with the swap. At least that far I was able to test it yet. The slalom videos of @spitsnaugle also dont make the impression of a car out of balance. Sure, 50/50 is the dream mark and would result in lower lap times. But I realy have the impression that this imperfection is within totaly acceptable limits.

On the other hand it is also possible to do a FI build on the FA20. I did Turbo builds before, for myself a 1.8T 20V in pretty much the same as a Golf Mk4. It was over 400HP and I realy liked the techniques and the Turbo torque and so one. But there were always things running on the edge. Finally it was the gearbox which was the weak point in that build. Everything else was optmized somewhen to hould up daily use and also rough driving. But the trans I had to overhaul or exchange every 8-10k miles. I didnt see any sence in expensive transmission swaps also available for those cars. I just dont want to spend more money for a trans then the whole rest of the car is worth. It came the day I decided to sell this car and save some money to build our house...

Hmm, 2 month later I purchased the 86, promissing to do no modifications on that car to be able to sell it quickly, just in case I need to. Now, find my mistake...

Long story Short, for my perpektive the LS swap was a great decission as far as I can say now. Sure, getting this thing street legal is still an open point. But the engine, the trans, axles and driveshaft can handle the power. They are not running out of spec. Under normal circumstances they will hold up daily use and also spirited driving for a long time. The weight penalty I have to accept therefore is absolutely fine for me. Pricewise a FI build with compareable durability and power is not cheaper and will not consume much less fuel. And the best thing: Turbo torque is nice. LS V8 Torque is just outstanding. I would say no 2L Turbo with 450HP will spool imidiatly the milisecond you hit the pedal at 1000rpm. And for now I just love it. Might be a consequence that Im already used to drive turbos with good torque + power and beeing kind of bored over the years.

[Irace86.2.0]

Weight distribution is important, but so is where the weight is distributed like is it central or polar, and of course where the weight is compared to the drive wheels, besides total weight and a million other factors.


Take the C8 Corvette. The weight distribution is 40/60, which is far from 50/50, but that extra weight over the rear wheels really makes a difference 0-60 and around a track.


I would assume any disadvantages the C7 had over the C8 because of weight distribution would only be that much worse with more weight further forward, if that makes sense. Total weight is definitely important too, and maybe it is more important than how easy it is to put the power to the wheels, but maybe not too. I don't know.

[TRS]

Some numbers:

0-100kmh = 4.1s (dry, normal Road, Federal RS-R 595)

I think with a little more Training and warm tire and road a 3.x should be possible. Traction seems very good. Once the clutch in closed full throttle in gear 1 is possible with no wheelspin.

11.75L per 100km with normal driving style, 1/3 Autobahn @ 130kmh, 1/3 over land, 1/3 city

About 18L per 100km @ spirited driving

9.5L per 100km "hypermiling" @ 100kmh cruise control

[R_E_L]

Unbelievable work, thank you for this gift to the community! Couple questions (they may be obvious but I'm still trying to familiarize myself with the details of these swaps). Does the stock emissions equipment for the LS/LT engines not fit in our cars? If I were ever to try something this crazy down the road I'd want to be road legal too, which is complicated in California. Also I've read that some people are not able to keep the front sway bar when installing these engines due to clearance issues, were you able to work around that?

[TRS]

With the mounts I developed and the GTO pan it's absolutely possible to keep the sway bar. Its all a matter of engine placement.

For california you are absolutely able to stay street legal. (from what I know about the regulations there) Only thing you have to do in addition to my swap is to implement the GM pressure sensor to the fuel tank and exchange the Toyota vacuum EVAP test pump for the GM solenoid valve. What Toyota is doing with a vacuum pump and a valve is done by GM with a valve only and the heat expansion of the fuel due to exhaust heat. Qiestionable is if the calculations done by the ECU for that test are suitable for the 86 fuel tank volume. But besides that the System should work if you add those two components.

Concerning the converters: No, the OEM converters will not fit an 86 chassis. But there are several good options out there. Just keep in mind that you have to Plan for about 600 bucks per converter to have a reliable unit and you need two of them.

After correctly setting up my exhaust System I was able to perform all internal emission DTC Tests for the GM ECU. That should be all for CA as far as I know. In Germany this is by far not enough. Only advantage is that the EVAP Regulations are less critical here, so I dont need that vacuum test stuff. This beeing said, the EU Version of the 86 doesnt even have this vacuum test System. Just a conventinal chaar coal filter. Thats all.

[Zer0]

Unfortunately in California you must use unmodified OEM cat's that came on the engine from the car that you sourced the swap from. You could get a kit C.A.R.B certified but thats a different route and will cost $10,000-$20,000

California dosen't care about how clean the emissions are. They focus on stopping swaps by making it way harder than it needs to be to meet regulations that are unnecessary to meet emission standards, or price you out of it altogether.

[Irace86.2.0]

Originally Posted by Zer0

Unfortunately in California you must use unmodified OEM cat's that came on the engine from the car that you sourced the swap from. You could get a kit C.A.R.B certified but thats a different route and will cost $10,000-$20,000

California dosen't care about how clean the emissions are. They focus on stopping swaps by making it way harder than it needs to be to meet regulations that are unnecessary to meet emission standards, or price you out of it altogether.

What's the clearance of the stock Camaro LS3 headers with the OEM cats in an 86 chassis?

[Zer0]

Originally Posted by Irace86.2.0

What's the clearance of the stock Camaro LS3 headers with the OEM cats in an 86 chassis?

Not sure I'm using a LT4 engine with C7 corvette manifolds and cats. I think camaro manifolds would be easier.

[Irace86.2.0]

Originally Posted by Zer0

Not sure I'm using a LT4 engine with C7 corvette manifolds and cats. I think camaro manifolds would be easier.

If the clearance is close, but obstructed then I’m sure a little bending and persuasion with a hammer could make it work.

[Zer0]

The lt4 manifolds and cats worked out for me but its not plug, and play.

[TRS]

The gen5 camaro manifolds should fit, but everything from there will be very problematic, especially on the left Hand side due to the steering column. I would gues one could need to raise the car from Stock height to even get the converters under the car. Routing arround the steering column and front axle with the camaro 5 Downpipe I would gues is impossible if you dont change the tubing.