FRS 4.8 LS swap

[kurty85]

Originally Posted by mrg666

Man, you bought the wrong engine!

I did not buy the wrong engine! Have you ever seen how much abuse little 4.8's can take? They have a 3.78 bore x 3.27 stroke with a longer rod than any other ls. This lowers piston speed, which decreases wear on the cylinder walls. Check out 1200hp 4.8 ls on google. Interesting read. I am shooting for 300 to the tire with the current setup and have 2 6765 billet precision turbos for later. I want to make 1000/1000 and it is entirely possible. Should come at 18-22 psi. Denmah on ls tech made 1078 on a stock 6.0 in a colorado. Bottom line, people throw away 4.8's and go for 6.0's, ls7's, etc. I got my engine for 500 bucks. Im in for a penny a pound to prove that 4.8's more than have what it takes!

[all4spl]

I hate to say this but this platform is not designed for 1000whp. the wheelbase is very short, car is light, and can only support but so much of a tire in the rear. Good looking build so far but it's going to be scary. What are you doing with the heater core lines?

[kurty85]

Originally Posted by all4spl

I hate to say this but this platform is not designed for 1000whp. the wheelbase is very short, car is light, and can only support but so much of a tire in the rear. Good looking build so far but it's going to be scary. What are you doing with the heater core lines?

I threaded the side of the waterpump and used pipe plugs instead of the tubes. The tubes literally have glue to hold them in so I just yanked them with heat and used a npt pipe tap and bought a summit plug kit. The heater core lines themselves not connected due to being in Guam and never using heat. I cut them back to even with the firewall. Maybe sometime later I will look at hooking them up.

[mrg666]

Originally Posted by kurty85

I did not buy the wrong engine! Have you ever seen how much abuse little 4.8's can take? They have a 3.78 bore x 3.27 stroke with a longer rod than any other ls. This lowers piston speed, which decreases wear on the cylinder walls. Check out 1200hp 4.8 ls on google. Interesting read. I am shooting for 300 to the tire with the current setup and have 2 6765 billet precision turbos for later. I want to make 1000/1000 and it is entirely possible. Should come at 18-22 psi. Denmah on ls tech made 1078 on a stock 6.0 in a colorado. Bottom line, people throw away 4.8's and go for 6.0's, ls7's, etc. I got my engine for 500 bucks. Im in for a penny a pound to prove that 4.8's more than have what it takes!

i read in your OP that you didn't like the turbo setup. If you are not able to setup a reliable turbo configuration with FA20, what makes you think a twin-turbo LS swap will be better? That is why, I thought the best option would be to aim the higher power withl a larger NA engine. Can't you get more than 300hp with this engine without turbo?

[kurty85]

Originally Posted by mrg666

i read in your OP that you didn't like the turbo setup. If you are not able to setup a reliable turbo configuration with FA20, what makes you think a twin-turbo LS swap will be better? That is why, I thought the best option would be to aim the higher power withl a larger NA engine. Can't you get more than 300hp with this engine without turbo?

My setup was reliable. I drove it from January of 2015 to December of 2016. I did not like the cam sensor issue I had and felt like it was going to go at any time. I had a very safe tune also. There are many people in this forum who have had issues with a turbo fa20. I would say many of the swaps are done because the FA20 blew up! A 4.8 LS n/a could probably get to 400-425 at the tire n/a with a nice cam and headwork but that is not enough. I want to see what the 4.8 can do with twin turbos. But I will get it going n/a first and sort out any bugs.

[wutsaiu]

If you can get 1000hp from a 4.8 and make it survive more than a few dynos and drag strip passes I will be impressed. I had 500whp from a 4.8 reliably but 1000hp is much more. I have to ask though, are you making a straight line car? The iron block isn't light.

[kurty85]

Originally Posted by wutsaiu

If you can get 1000hp from a 4.8 and make it survive more than a few dynos and drag strip passes I will be impressed. I had 500whp from a 4.8 reliably but 1000hp is much more. I have to ask though, are you making a straight line car? The iron block isn't light.

4.8's are well proven to perform well under boost and all anyone needs to do is read up on the subject. I chose the iron block for cost. Plus they handle boost well. Block weighs 216 dry. But i have also taken off power steering, ac, all the heavy parts and swapped for ls2 parts. Probably will do drag strip at first. What was the part from dss to convert the rear end you bought? Different pinion yoke or 4 bolt converter to 1350 yoke?

[all4spl]

there is an 89lb different between iron and aluminum. it isn't too terrible.

[wutsaiu]

Originally Posted by kurty85

4.8's are well proven to perform well under boost and all anyone needs to do is read up on the subject. I chose the iron block for cost. Plus they handle boost well. Block weighs 216 dry. But i have also taken off power steering, ac, all the heavy parts and swapped for ls2 parts. Probably will do drag strip at first. What was the part from dss to convert the rear end you bought? Different pinion yoke or 4 bolt converter to 1350 yoke?

I contacted them (DSS) directly and asked them for the piece. I don't believe they have it for sale on their page but since they make driveshafts for these cars I knew they could get one. I don't know if mine is 1350, might be 1330.

[Helios]

Originally Posted by all4spl

there is an 89lb different between iron and aluminum. it isn't too terrible.

Exactly! And the relocation of the battery to the trunk helps to offset that added weight.

[kurty85]

Finally had enough of the clutch master cylinder getting in the way of the valve cover. Move the MC to the right and bent the linkage inside the car. Clears the valve cover completely now. Also ordered a driveshaft from DSS. 3" aluminum and 48 1/8 inches long. Used an FRS 4 bolt at the rear and GM 26 spline. Was surprised it came to only 509. Just need a wiring harness now and exhaust and it should be able to run soon.

[kurty85]

Finally making some solid progress. Coolant system is done, filled up, and bled. Installed the dipstick, filled up the oil with no leaks. Put the coils on the valve covers, new spark plug wires installed. Was able to bleed the brakes and the clutch master cylinder. Rear coilovers on. Starter installed. Next is to tighten up everything in the rear and reinstall the back half of the exhaust. Next up is wiring, wiring, wiring...Got my MRS device and removed all the dash pieces to put it in. Waiting on the PSI LS2 E40 wiring harness, DSS driveshaft, and GTOG8GTA shifter.

One question about the harness is that it is made for 2 side knock sensors, but I have 2 in the valley. Anyone know of an adapter from single wire knock sensors to ls2 style 2 wire knock sensors?

Figured out which exhaust manifolds I will use too. LS3 exhaust manifolds exit in the center which should make it easy to hook up (2) 2 bolt flanges to a y pipe. Got an adapter for a 2 bolt to 3" v band so I can use the whole rest of my full blown exhaust, which is 3" to a vibrant 5" muffler.

[all4spl]

Do you think the GTO shifter will align perfectly or will you need to make some changes? I also have the F body trans and that may be a good solution for me.

[MRS-Colin]

How would you rate the installation ease of the MRS device? were the instructions thorough enough?