Tibby Posted May 25, 2011 Share Posted May 25, 2011 How do you like the 4.8? I've been tossing the idea around of going with a 4.8 instead of the 6.0L. I have this tremendous fear of spending more money then needed just to make my car less fun. Most of the internet trolls peg the 4.8 as a dog. How does it compare to the 5.3 on and off boost? Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 26, 2011 Author Share Posted May 26, 2011 (edited) The 4.8 with the turbo I've got spools pretty darn fast. So its hard to determine how it is out of boost. Compared with the 5.3, I have to run about 2 - 2.5psi more to make up for the smaller engine. But that's okay, on the street the car is completely useless anyways. Spins the tires very badly if I punch it while cruising down the highway at 65mph. If you asked me if I'm disappointed that I went for a 4.8 rather then one of the others, I would say no. Nothing beats telling people its the smaller engine out of the bunch, and watching their reactions. I also ran the 5.3 with 317 heads, as well as my current motor. So I'm sure the low compression really doesn't help too much when its out of boost anyways. They both feel the same. Edited May 26, 2011 by ColtGT4g63 Quote Link to comment Share on other sites More sharing options...
Cable Posted May 26, 2011 Share Posted May 26, 2011 Next time throw your 5.3 dished pistons (along with the 5.3 rods) in the 4.8 and you'll lower the compression even more. Quote Link to comment Share on other sites More sharing options...
Tibby Posted May 26, 2011 Share Posted May 26, 2011 If you asked me if I'm disappointed that I went for a 4.8 rather then one of the others, I would say no. Good to hear. I really wanted to go with the 6.0 at first for the ease of getting me where i wanted to go with power. But the more I thought about it I'm not sure that the bigger cube motor will make my car more fun. Faster for sure but fun I don't know. Its easy to have your judgement clouded with big HP numbers and make your car more serious then a street car should be. Sorry to clog up your thread with my rambling but It's very hard to find any info on the LR4 motors outside the towing obsessed truck world. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 26, 2011 Author Share Posted May 26, 2011 (edited) Tibby - I'm sure I'll be able to make enough power in my 4.8 to run a 9. Which should be plenty. I swear the most fun I've had in my car was with the 6spd manual and the 5.7, I could jump in and drive that thing anywhere. And also run low 7's in the 1/8th without having to worry about a thing. Things are more complicated now and I certainly don't have as much fun with it outside of the track, But when I'm at the track its a complete blast! Cable - The piston tops of my old 5.3 are flat tops. Check it out: So the only difference between the 5.3 and the 4.8 is the stroke? Maybe I should turn the rev limiter up?? Edited May 26, 2011 by ColtGT4g63 Quote Link to comment Share on other sites More sharing options...
Cable Posted May 27, 2011 Share Posted May 27, 2011 What year was the 5.3? I ask because no Gen III 5.3 had flat top pistons prior to going to Gen IV and even then the only 5.3's that had 243 heads (same used on the LS6/LS2) got flat tops, the rest had dish pistons. So if your 5.3 is a Gen III, I'd be willing to bet its really a 4.8 litre, although it was sold to you as a 5.3 (a common scam these days). Both 4.8's and 5.3's share the same block. The stroke (and rod length) is the primary difference between the 4.8/5.3. The 4.8 has a stroke of 3.267". The 5.3 has a 3.622" stroke, which is also the same stroke for all other LS series engines except the 427 LS7 (4.00"). Unless the pan is pulled to check crankshaft casting numbers, there is no easy way to tell the difference. If you can get the casting number off the '5.3' crankshaft, I can confirm the stroke in a few seconds. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 27, 2011 Author Share Posted May 27, 2011 That's some good info to know. I'll have to go measure the stroke to confirm, but after reading what you wrote... I wouldn't be surprised to find out that it really was a 4.8L. And with that being said. I guess I really ran a 6.6 and trapped 106 with a 4.8! Wahoo!!! Quote Link to comment Share on other sites More sharing options...
sq_creations Posted May 27, 2011 Share Posted May 27, 2011 Sucks to hear about your old motor but happy to hear you got it back together and running strong again. Nice job bro! Quote Link to comment Share on other sites More sharing options...
Cable Posted May 27, 2011 Share Posted May 27, 2011 I am seriously thinking about leaving my LQ4 out of my car and tossing in an extra 5.3 I have sitting in my garage at this point... That why I don't trash my fresh 6.0 in an accident... Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 27, 2011 Author Share Posted May 27, 2011 I've ran that old motor SOOOO lean, and made plenty of mistakes on it. And it kept running like a champ. These truck motors are pretty darn forgiving! Quote Link to comment Share on other sites More sharing options...
RebekahsZ Posted May 28, 2011 Share Posted May 28, 2011 How much driveshaft, diff and axle carnage have you had along the way to getting to this point? Please list current driveline setup, gearing, wheels and tires. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 28, 2011 Author Share Posted May 28, 2011 (edited) Q45 rear diff with the custom axles. 280Z stub axles, regular 'ol 2.5" steel driveshaft with 1310 U-joints. There really isn't much diff angle at all. 3.54 gears, Mickey Thompson E/T drag 26 x 8.5 x 15 with tubes and wheel bolts / locks mounted on some stock wheels. still 4 lug in the rear. I broke two axles when the rear end stuff was stock. Have not broken anything since swapping to the set up listed above. I've done a best 60ft of 1.483 And done countless transbrake launch's Edited May 28, 2011 by ColtGT4g63 Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 28, 2011 Author Share Posted May 28, 2011 Just measured the stroke. Its a 4.8! WAAAAAAAAH!! Quote Link to comment Share on other sites More sharing options...
Cable Posted May 29, 2011 Share Posted May 29, 2011 Just measured the stroke. Its a 4.8! WAAAAAAAAH!! Figured as much. Sorry to be the guy to break the news to you dude. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 29, 2011 Author Share Posted May 29, 2011 No worries. It went fast, and is now resting in peace. I know what to look for now when motor shopping, so I do appreciate the info. Quote Link to comment Share on other sites More sharing options...
Tibby Posted May 29, 2011 Share Posted May 29, 2011 Now the billion dollar question is... Why does it take a few more psi to make the same power if the motor is still on the same 4.8l platform? Air leak, bad compression, change in intake tract? I don't want to pee in anyones cheerios but this just struck me as odd. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted May 29, 2011 Author Share Posted May 29, 2011 I thought the same thing and have come up with a couple possibilities. On my old motor I had a couple things different then what I've got on my new motor. Old motor: I used my "bigger" S400 turbo. The one with the 1.32 A/R exhaust housing, and 96mm wheel. New motor: I'm using a smaller S400 with a 1.1 housing and 83mm exhaust wheel. Old motor: used the MegaSquirt to control the ignition, which didn't seem like a very reliable way to do it. When looking at the timing with a timing light, the timing mark would jump 5* - 6* So I may have been running more timing before then I thought I was. New motor: Using the MSD 6010 unit to control the ignition timing. At the track, I noticed that my trap speed did not change too much when going from 8psi - 11.5 psi. It stayed around 100mph. When I set the boost up to 12.9psi, I also bumped the timing from 13* up to 15* and it trapped 3mph more. So I really don't know if it was the timing, or the boost that helped. All I know is that on my old set up I was able to get 106mph trap speed out of it,(with a messed up launch even) at about 11.X psi. So I may throw the larger turbo back on there and give it another try. I'm going to the dyno in 2 weeks here, so we'll see how well this little 4.8 can handle some power. I am also going to be running the car on E85 from now on. So it should make things interesting. Quote Link to comment Share on other sites More sharing options...
ColtGT4g63 Posted July 31, 2011 Author Share Posted July 31, 2011 Okay guys, I know I am long over due for an Update so here is one hell of an update. Back in May I went to the track and wasn't able to get more then 103mph out of it, at nearly 13psi. In the past at the same boost I've gone 105 - 106mph! Here is a video I edited of my night out at the track back in May. So after this track day I started running E85 in the car, because race gas is just getting too expensive! I also took the car to the dyno and put down a max of 504hp and 459tq. This was at about 12 - 13psi. Looking at the dyno graph there is a pretty steep drop off just after 5k. So I was racking my brain trying to figure out why. *light bulb goes off!!!* Way back when I trapped 106, I was using an LS6 intake, and a bigger exhaust side on my turbo. Makes sense I guess. And when I went to the track in may, I was on an LS1 intake and a smaller A/R exhaust housing and smaller turbine wheel. So After the dyno I swap the intake back to the LS6, and swap the turbo back over to the larger exhaust side turbo. Also had to upgrade the fuel system a bit due to the E85. So I make all the changes, and take the car back out to the track last night. VERY pleased with the results! 1st run: 6.5 @ 106.8 with a 1.49 60ft.! 12.7psi 2nd / 3rd runs 6.6's @ 107 mph. 1.5 60ft's 14psi. 4th run 6.5 @ 108.4mph with a 1.50 60ft. 15psi. At this point I was at 100% duty cycle on my injectors and decided to call it a night. I drove to work that morning, drove to the track afterwards, then drove to In n out, then drove home. As I upped the boost at the track, I noticed that my traction started getting a little worse. I guess I'm finally at that power level. Here is a video I edited of some of the dyno stuff, and then one of my runs out at the track last night. enjoy! Quote Link to comment Share on other sites More sharing options...
Turbo Meister Posted August 1, 2011 Share Posted August 1, 2011 Looking Good!!! Getting Better Every Time... Quote Link to comment Share on other sites More sharing options...
sq_creations Posted August 1, 2011 Share Posted August 1, 2011 Very Nice. So what converter did you end up going with? Quote Link to comment Share on other sites More sharing options...
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