aussie-revhead

Hi guys, there is a huge wealth of experience here and I am looking for advice on a build. I have been building an iron block motor for an N/A build for my weekend street car but family stuff got in the way and the build stalled, then ideas change on the way too so I am looking at putting a single turbo on it. I'm not looking to break world records but I'm getting older and I want this build to be worth it. So what do you guys think I should realistically aim for in a streetable turbo LS? My LY6 block is 4.065 so the walls will prevent massive boost right? Should I keep this thing N/A and start again on a turbo only motor? I want to run it on premium 98 pump fuel to keep it simple, E85 isn't common here. It will have an automatic and the donor body is yet to be decided but most full size Australian cars are around 3800lb.

I know stock LS1 turbos get some serious power with bolt-on gear only but I want it to last too, so I am happy to upgrade what is needed but an LSX block and luxuries like that are way beyond the budget.

My personal goal is to run anything in the 9 second zone (a boosted LS should easily do that) and running an 8 would be amazing.

I am open to ideas, feedback, anything you guys want to share, so fire away.

Cheers

stevieturbo

Space, budget and ability will dictate what can or cannot be done. Whether that's your ability or that of fabricators you choose. Single turbos can take up a fair bit of room.

But with a strongly built trans, and engine etc...9's should be easy. 8's perhaps less so, but comfortable 9's should not be a problem. If you intend on using 98RON only, then I would definitely keep the CR to around 9.0:1, no higher.

If you may add methanol injection or similar, then you could bump that a bit higher...but TBH, I'd still err on the safe side. There's negligible loss for big margins on safety vs pushing higher CR's

Cant comment on wall thickness of the block though

stevieturbo

Crikey...didnt think this one was so old !!! I think there might have been another one on the forum

https://ls1tech.com/forums/forced-in...ion-wagon.html

stevieturbo

Or another build ( he's on this forum too ). Clearly much milder, but fab basics etc are all still same challenges.

https://www.ls1gto.com/forums/showthread.php?t=837586

TastyBacon

iTrader: (1)

As I understand it, 98 RON is equivalent to 93 AKI. Why limit yourself to 9.0:1 compression on 93 octane pump gas? Plenty of people stateside running 9.5-10:1 on "premium" pump gas, which ranges anywhere from 91-93 AKI.

stevieturbo

How many of them are running 8's or low 9's on that pump gas only ?

The only limitation will be a CR that's too high and you become knock limited.

9.0:1 CR is in no way whatsoever a limitation to making power, it will help make the power safely.

TastyBacon

iTrader: (1)

My fault for reading too fast, I didn't catch the 8s/9s goal in the original post. Carry on...

Forcefed86

iTrader: (4)

8-9’s at 3800 lbs is no small goal. Is that without driver as well? Without a ton of $ in parts it won’t be very reliable or what I’d call “street friendly” and comfortable without serious cash. Get something light weight and/or give up all the creature comforts and you can fudge that a bit. I always try to tell my friends it’s easier to own 2 cars than to make 1 dual purpose car. Get something lighter weight if you want to run 8-9s with it. Then buy another to cruise the streets and you’ll be money ahead. Def. don’t run a hogged out bore 6.0 for those goals.

IMO “building” and engine doesn’t mean it will be more reliable most of the time. Not only are you at the mercy of a machine shop to get things right... (rarely happens for me) but fact is at these power levels things go wrong, period. Built engine or not, something will break eventually. So why have a mint tied up in the long block? Personally I like to keep the engine long block bone stock. Add a cam/springs and spend the big money on the driveline, turbo system, fuel system, and ECU. When every things “right” the Stock short blocks are damn tough. Buy a spare long block (or 2) and have it ready to drop in. Design the turbo kit in a way that makes it friendly to remove. Then plop in new engines as necessary. Engines are the cheap part and should be treated as disposable IMO. Unless you plan to run a nice aftermarket block to match an aftermarket rotating assy you aren’t doing yourself much of a favor. The good rotating assembly will just wiggle around in an OEM block at big load/power levels.


I’ve run basically “cam only” GEN4 4.8, 5.3, and 6.0 in my 3100lb car with very street friendly gearing. All have easy 8 sec potential. The 6.0 is the best suited IMO as it works best with the least amount of RPM on a factory intake TB etc. The 5.3 and especially the 4.8 need to be revved higher. So aftermarket top ends, intakes, etc suit them better. I also don’t like the shorter gearing needed to keep the little motors happy on a street car. That can be offset with the OD 4l80e but again you are adding big expense there.

stevieturbo

I wouldnt see 9's being difficult, 8's will definitely be a challenge though without some assistance in terms of fuel

Forcefed86

iTrader: (4)

Guess it depends if we are talk’n a 9.0, 9.5, or 9.99. Pretty hard at a 4000lb race weight. While being comfortable and “street friendly”. Esp. if they want all the creature comforts. OD trans, AC, etc.

Matt Happel’s truck is a good example. 3850ish lb race weight going high 9’s around 900whp. That’s cutting a lot of corners with low reliability and lacking all the comfort amenities. Add more weight, ride comfort and reliability into that build and the budget would need to go up substantially.

https://ls1tech.com/forums/forced-in...e-3850lbs.html

stevieturbo

My own car is manual and around 3800lbs. Someday I will get back to a dragstrip and would expect to comfortably run 9's, hopefully mid 9's.
Whilst I do also use water/meth, I'd be pretty sure I could still run 9's on pump alone too.....but I never built mine to specifically run pump only for that sort of use ( although most of the time I do ) so it's not a fair comparison as to how far it could be pushed when built with that in mind.

If mine was an auto....it seems most can knock almost a full second off their times vs manual. Although I doubt mine would drop that far

Last time I was at the strip a couple of years ago....before the ******* clutch slipped ( which is another whole story ), I did 10 flat at 152 with a poor 60ft of 1.76s
Next run was a little better until 3rd gear then the clutch just slipped like ****. If the 60ft dropped to similar to what I'd done 10 years ago circa 1.5s, the time should very comfortably be mid 9's

stevieturbo

https://ls1tech.com/forums/forced-in...0-pumpgas.html

aussie-revhead

Thanks for the replies guys

@forcefed - Those are great points but we don't have any light weight cars here that can take a V8 easily, we have some old 70's cars that are small enough but that's not what I want to drive and I'm not looking at building a trailer sailor or the equation would be very different (super light tube car with a turbo LS would be an exciting prospect). I know of a guy with a single turbo on a stocker 5.7 (common LS over here) and he has run 10.1 but yes he has broken a few shorts on the way too.

What car are you using at 3100lb?

I'm not really sure which way to go with this build, it's not our main transport so I don't expect it to be smooth and pull 30+ mpg

@stevieturbo - Clutch slipping 152 mph run .... You sir should be aiming at 8's with an auto and full respect to a mid 9 with a manual.

stevieturbo

the clutch had held for a few runs around 152/153 after the initial slippage, but then as I tried launching a little harder etc, it gave up and started slipping again.

But there is no reason you cannot achieve the goals and be very smooth etc. 30+mpg is dreaming though lol