SC400 to be faster then 400hp Vette?

[Anaema]

don't bother with extrude honing. all it does is make the ports bigger and cleans them up a bit.

thats the point... more airflow means same HP on less boost. which means less detonation.

 

[Pro]

all NA flow figures at however many inches of water are irrelevant once fed 3psi or more of boost.

porting and polishing (or extrude honing) does very little in the way of making a significant difference to anything except a worked NA engine.

and there is no way you'll run mid 12s in a soarer with an NA 1UZ cheaper than if you force feed it.

i guess you could just feed it a 300hp shot of NOS but then where's the fun in that?

 

[Anaema]

but hey, every little thing you can do to beat those damn corvettes.

 

[Pro]

it's expensive for the amount of gain you get.

you could get the same power by winding in a few more psi of boost.

 

[Anaema]

im not gunna argue about it any more because its not my car, and its not my choice what mods get made.


a high boost 1UZ could use a big intercooler with a nitrous intercooler kit filled with CO2 to freeze the air.

 

[jibby]

Pro240c - 300hp and a shot of nos is not all that bad, it has been fun and very reliable to me. It really gets the car moving when ever you need it too.. Ask me if I would rather be running a forced air induction? Absolutely, but I would prefer to supercharge rather then turbo charge, I just don't appreciate the delay time with turbo's and I know more about supercharging in general. Turbo's also tend to break easier and require more tweaking then a good supercharger setup. Atleast that applies to American Chevy's from what I remember years back, maybe turbo's have improved since.. I always remember my turbo's losing boost over time, especially with the 300zx twin turbo I owned, just would fail regularly after abusing and racing the car...

In regards to your differential ratio advise, my setup is very rude at lowend, don't think changing the ratio would help all that much, and it would reduce my top speed and throw off my speedo. I am not to sure I want to mess with that. When I installed the 1993 Supra tt torsen LSD on my sc400 I believe it had slightly different gearing ratios then the stock sc400 non LSD? I may be wrong but I noticed a change when I swapped, for the better.

However I am jazzed up, why you ask? I just got my rims back today and fat new rear tires, and after 3 months, I finally got a UPS confirmation that my headers and Y pipes will come in tomarrow's mail. Got my EGR blocker kit ready. So it is all coming together with my ride. My car was quick before, but after the electric fan swap, tuning, rewiring the grounds, headers and Y pipes, and the wider rims and tires, I expect my car to run faster 0-60, I believe in the high mid to high 4's. Your Tranny suggestions have been noted, thanks to all.

Ps. Pro240c can I borrow your automotive knowledge, it sounds like you really know your stuff....thanks

 

[Pro]

thats the point... more airflow means same HP on less boost. which means less detonation.

good tuning like i mentioned will eliminate any detonation.

jibby, the 300ZXs were notorious for being an unreliable system if not maintained PERFECTLY by Nissan.

turbochargers and superchargers are as reliable as each other these days - the older ones were unreliable only if you shut the engine down hot. the oil would stagnate and heat up in the core and fry it. you used to have to fit a "turbo timer" to idle the car after driving.

these days, water cooling means this won't happen half as easily. it can happen, but just idling at a set of light will be enough to cool the turbo down.

there are a number of tricks to improve spool up time, including pipe reducers, bigger cams, lightweight impellers and ballbearing cores.

and thanks for the compliment but there are many more people on this forum who are WAY more knowledgable than me. i just take my experience from crazy things i used to do with weird engines in my spare time as a high school student.

 

[jibby]

Well 240... you sound like a pro to me...and I guess turbo cooling has come along way since I last checked, which was around 8 years ago when I owned the 300zx twin...

I can't resist in my excitement - check out the difference in my rears now. I am not bragging, as I know my car is inferior then most on this forum, and these tires are not as fat as some either, but for me I am just thrilled. Those are stock sc430 tires on the smaller wheel.. Should be getting some better traction now I would think.

 

[rdm20fan]

rdm20fan- This does sound promising on what you said you did to build up your tranny, how much hp was your tranny supporting after the upgrades? This is the info I was looking for....I may be pm'ing you shortly, I hope you don't mind...

I don't mind at all. I'm not on this site very often though.
I'm making 510 at the rear wheels, and have not had a problem with the trans failing. When the trans was stock, it failed all at once though. no sign of slipping, and it went with 370RW about 2 weeks after the turbo install.

Raybestos Blue Friction disc, and Koleen steels are susposed to hold 300% over stock. but that doesn't mean something else in the trans may not go instead.

We changed how hard the trans shifts also. It's not the smooth shift it was before, but it's not rock hard either. it's much more of a sporty shift.

Chris is looking into fitting more clutches to also increase the holding capasity, and very firm shifts, but I don't think this would be what your looking for.

Hope I can help, and share my experiences with anyone who is interested.

 

[cjsupra90]

Jibby, my suguestion is to run turbocharger over supercharger. The bad part about a turbo is they tents to be more work and cost to actually install then a supercharger and is the reason why most american auto manufactures still tend to side with superchargers. There are a number of bennifits that the turbo has over the suprecharger. For one, as pro240c points out, spool up time is no longer really an issue as long as its sized correctly and you get the extra goodies. Other bennifits are if you use a blower style supercharger, they are not as effiecent as a centrifical compressor (i.e. turbocharger or paxton, vortec, ect. style supercharger) and blower style chargers are a lot harder to intercool which is something that you really want. Other bennifets are, if sized and done correctly, the turbo will waste less power from the motor (in the way of added backpressure on the motor) the pressurize the intake then any belt driven compressor. I know that there are a number of other bennifits that are infavor of the turbo but they are not comming to mind at the moment. (long rough day.)

Good luck in your quest to beat a vette. not easy, but can definitly be done.

(remember, the vette is a fair bit lighter also so you'll need more torque and power)

 

[jibby]

RDM20...Wow that must be one fast automatic sc400 you have, fantastic... I was starting to wonder if anyone has even tried modifying the stock tranny, good work. I would love to run my SC up against yours 0-80, I am very sure you would pull away with 510 at the rears. How much hp is that at the crank? That's right you can chirp those rears in your third gear, mine only chirps in second....Sweet...

Curious did your stock tranny blowout in the second gear and what is the pricing on the raybestos blue friction disc, and Koleen steels? Being that you live near Chicago these parts can be aquired in the states. That is good news. 510hp at the rears, wow, that would work for me.. There is hope yet....Thanks for the replies.. Also sorry to see your Chicago Bears are not in the SuperBowl they did have a great Defense just need a little more offense...See ya

 

[jibby]

cjsupra90- Thanks for your thoughts on the differences between Supercharging and Turbocharging.. I guess turbo's have come along way in the last 7 or 8 years from what I am reading. I just thought turbo's are headaches waiting to happen, finicky, delayed reaction, overheat and fail easily. I guess that has all changed... Anyway, I still am in love with the blower/supercharger, it appears that the T.S. Whipple gets the job done and then some on a few of these SC's, and what about all the Soarer owners using and running those Eaton's. I haven't heard of two many complaints on those superchargers, however, I have read many threads with turbo problems and complaints with many misc. problems.

I must say I really don't know enough about the turbo's to speak intellengently about them, but I have done my homework on supercharging. I appreciate the input but I am still a ways away from introducing air forced induction to my sc, so I will think about this all later and live with my nos for now. See ya

 

[Anaema]

turbos get better top end HP than any kind of supercharger. it has to do with running the supercharger off the crankshaft.

 

[Pro]

not exactly Anaema but close - a good supercharged setup is still quicker that ANY turbo setup because it has more average power.

the supercharger runs off the crankshaft because the only other way to drive it is electrically - and we all know how plausible that idea is (turbozet anyone...?).

that said, there's a guy over here called Andrew Jordan who runs i THINK an MP112 on an SR20DET. he removed the turbo and has MORE top end grunt than he started with.

with supercharging setups (and i only found this out recently) you can basically assemble a highly strung out NA engine and bolt a supercharger to it (minus the 13.0:1 static CR and all!). whatever mods work with NA engines work with supercharged engines.

big NA mods also work with turbo engines, but you have to select your compressor sizes carefull so that it provides +ve manifold pressure once the engine's volumetric efficiency increases otherwise the turbo will overboost. not so bad if you're only running low boost, but if your engine can only handle 1bar and all of a sudden it sees 1.6bar - well, think *BANG*.

 

[jibby]

Talk to me pro240c, supercharging is the way for me....

 

[hnknrob]

whatever mods work with NA engines work with supercharged engines.

n/a and forced inductoin require different cam durations as well as the lower compression ratio you mentioned.

a couple advantages of turbocharging over supercharging are a) its alot easier, as well as cheaper, to change boost levels of a turbocharger than a supercharger and b) ive had bad experiences with supercharger belts slipping, which sucks beyond explanation when you hear a slipping belt while youre trying to beat the car next to you down the 1320.

now there is a fix for the centrifugal superchargers' belt slipping, you switch from the serpentine belt to a cog belt and pulley system. but this switch is hard to source parts for in alot of cases, as well as causing quite a bit in the way of fitment issues.

 

[Pro]

n/a and forced inductoin require different cam durations as well as the lower compression ratio you mentioned.
.

i suggest you talk to Barry from Datsport in Adelaide then.

he built a 180B coupe with a supercharged L18 back in the mid 70s that BLITZED the SBC field in speedway and held the lap record until only a few years ago.

this man has been building SC engines for years and his experience contradicts the very statement i have quoted.

like people saying you can't turbo a large port (bridge or peripheral) rotary. you can, and i it has been done successfully WITHOUT relocating the port position. it's all to do with compressor selection.

you choose a turbo or supercharger that supplies boost at a higher revs to compensate for the overlap. at higher revs the overlap is pretty much eliminated because the VE of the engine has increased to a certain point that allows boost to build safely.

so, you choose a turbo with a bigger exhaust housing (A/R 1.15+) or a larger supercharger (M112 over an M60 for example) to make the charger boost higher in the rev range.

you can run huge overlap and have a large turbo/supercharger.

and i will prove it with my new setup.

 

[hnknrob]

this man has been building SC engines for years and his experience contradicts the very statement i have quoted.

im not saying you cant run a cam(s) with lots of overlap. but your statement contradicts my experience as well as the reccomendation of any camshaft manufacturer i can think of, as well as most of north america's drag racing teams and their engines, past and present included. like i said, im not saying you cant. im just saying in my experience, its not necessarily something you should.

one thing ive just realized though is it seems that north american and australian theories on what makes a superior straight line vehicle have gone in somewhat different directions.

 

[Pro]

true - we have the only 8.5 sec untubbed street car too (rotorworx KE20 corolla).

a lot of olskool ideas about what works and what doesn't can finally bite the dust thanks in large to fuel injection. it seems that in the US, EFI is still in it's infancy which is wierd because a US company put the idea in a motorvehicle in the mid fifties (desoto i think? had a 230something cube hemi in it).

you are 100% right when it comes to "other" people's recommendations - like cam makers and racers etc.

circuit / oval track / corner racers will swear you can't do it, drag racers will swear you can. look at a funny car - massive overlap, 13.0:1 static CR and over 2bar of boost should be a combo that blows up. often it does, and these engines need a rebuild after every pass but these are the extreme side of the coin.

track racers need good bottom-midrange to top redline performance with no lag. this means minimal overlap but lots of lift.

my point is either can be done - and quite successfully, even on a street/drag car. you just need to pick your cams and compressors carefully for what you intend to use the car for.

to say it's wrong, a bad idea or can't be done is nonsense. it's the matching of two glorified air pumps in series - it's not that hard.

 

[Pro]

i'd like to hear from more people on this theory too.