Random Ls question

[L67ss]

Oh. I was meaning because the boost kicks in at a lower rpm.

 

[86pontiac2+2]

Random answer:
Start with like 15:1 compression, port match everything, use the smallest pulley available, shot of 300hp NOS, E85, faucet size injectors, humongous fuel delivery system, improved oiling/cooling system, TUNE and hope for hp to crank numbers to get remotely close. Or turbo it.

 

[motorheadmike]

Could I have made more power with a turbo? Sure. But, turbos don't have the same street presence as a blower with straight cut gears and a thundering exhaust note.

 

[L67ss]

Or low rpm torque. I have a buddy with a 99 Monte with a turbocharged 3800 easily making 100 more HP than the supercharged 3800 in my 97 Monte yet they both run nearly identical quarter mile times

 

[UNGN]

Or low rpm torque. I have a buddy with a 99 Monte with a turbocharged 3800 easily making 100 more HP than the supercharged 3800 in my 97 Monte yet they both run nearly identical quarter mile times

A turbo 3800 with a loose converter will make more torque than any tires on a Front wheel drive 99 Monte can handle. If the times are identical because of wheel spin, that is a dumb comparison. My 3.8L runs 11.50@118 and spools at 2400RPM. I bet it makes more "low end torque" than an equivalent supercharged motor.

An automatic car with a turbo should be launching with the turbo fully spooled. If it isn't, the driver is doing it wrong.

Operator error is not the turbo's fault.

 

[L67ss]

Actually on a 4t65 you wouldn't want engine at the rpms to fully spool. Would scatter the trans all over the track lol

 

[81cutlass]

Why do you want or need 1000hp? You want to run 8's? Say hello to billet internal th400's, driving around on MT ET pro's with spools, cable drive fuel pumps and forged rotating assemblies. Can it be done on more stock stuff, yeah, but its going to take years of testing.

Turbo's are to a point more efficient than blowers since you can harness the lost thermal energy of the exhaust a bit.

But arguing efficiency is all BS for hotrod world. We don't care about the VE of the engine and the minor fuel consumption difference between them. A 700hp running at 65% efficiency is the same as a 700hp engine running at 72% efficiency. Marginally higher fuel and air consumption? Meh, theres bigger fish to fry.

Honestly, get a used C5/c6 vette blower from an AAcorvettes kit or something and stick it on whatever LS engine you want. Or buy an LSA blower used on ebay and the adapter plates or a 6.2 square port and a cam and make 600hp. Do 70mph rolling burnouts on anything but a drag radial.

 

[L67ss]

Oh I'm not trying to build it. Just a local guy claims to have built it and the parts list didn't add up to me. Also no dyno sheets lol

 

[64nailhead]

But yeah compared to each other at a given boost level(let's say 10-11 psi like my dd) parasitic loss is almost equal. Now on a supercharger the loss comes at a lower rpm as does the boost

And what do you think drives the exhaust running the turbo? Yup the crank. Again no such thing as free hp

Ive read actually comparisons and parasitic loss is roughly the same

Wow - this is some misinformation. Parasitic loss between a turbo and SC is almost the equal, the crank is running the turbo, - no, no, no.

The parasitic loss of a SC in comparison to TC is an exponential function of boost level. Turbo's are driven by a combination of heat and exhaust pressure. Saying a turbo makes no power at low rpm's is beyond incorrect. If one could load (make heat) the motor at low rpm (low exhaust flow), then the boost will be equivalant and so will the HP and TQ on the same motor. The issue with a SC (or blower) is that as the rpm's increase linearly, the parasitic loss (wasted HP) increases exponentially.

Which is better? Depends on your application and budget. Turbo = low cost and SC = high cost. When street driving (red light racing) a SC is hard to beat below 7000rpm's. But if max effort is the goal, then the turbo will run right past the SC IMHO. Also remember what is occurring when the wastegate dumps, the turbo is dumping excess energy at no expense to performance as rpm's increase, but the SC is requiring increased power to be driven whether the boost controlling device is dumping boost or adding boost.

 

[L67ss]

Does the turbo move without the crank moving? No. And with the bbv open drag would about the same as a turbo. And I don't care if the exhaust coming out of the head is 5000° it'll still lag as you need airflow to spool a turbo. And yes output for out put cost to run HP wise is almost dead even