Jump to content
SAU Community

Turbo maximum hp question

Cool Hand Luke

By Cool Hand Luke,
in Engines & Forced Induction

 Share

Recommended Posts

Cool Hand Luke Community Regular

Cool Hand Luke

Posted
Posted

If a car is developing the maximum hp that a turbo can develop, and you do other modifications to the car such as head, cams etc will you get a hp increase? The reason why im asking as the turbo i currently have cant develop any more hp on the car, no matter how much more boost i run. Im rebuilding the engine (sr20) with solid lifters, cams, rods and head modifications and are curious if the turbo will hold the engine back.

Im running an external hks wastegate but its quite small, what would the effects be if the wastegate is too small? Or what advantages are there going to a larger one?

Link to comment
https://www.sau.com.au/forums/topic/62867-turbo-maximum-hp-question/
Share on other sites
Cubes Grand Master

Cubes

Posted
Posted

Once you run off the efficiency envelope the turbo will heat the air. At some point superheating which is why you don't see any power Increase when increasing boost, sure slightly more air will enter the motor with the higher boost but the draw back will be that it is hotter and less dense.

Headwork, cams etc improves VE (cylinder filling) which allows you to cram air in to the pots with less resistance.

More air = more power.

Less boost = denser air = more oxygen = more power.

Smaller wastegates will allow you to hold higher boost levels without boost tapering off. The only problem with them is if you select a wastegate to small it could cause boost creep where boost keeps heading north as you increase the rev's.

I'm sure you have heard of this happeneing on some bad T3/4 highflows when their internal gate hasn't been enlarged.

A wastegate that is too large, will increase spool time slightly in turn reducing the power under the curve slightly.

It may even be so extreme as boost has trouble being held constant as when the large wastegate opens it bypasses soo much exhaust gas boost will drop below its set level, the wastegate will then close and may cause a wavering boost level.

Run the turbo with the new motor and if you want more power upgrade then. :D

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • PranK
      Chris' Toyota Mark ii JZX110

      By PranK · Posted

      This looks great! Awesome to have the 5 speed with an LSD in this. The Recaro's look like SR2's or SR3's. It's a shame they've been retrimmed as they would have looked sweet in their original colours. I think I'd want my agent to be a little more up front and informative too. I've never imported but I reckon it would make me a little nervous, so the more info the better.
    • soviet_merlin
      Duncan's V37.......race car?

      By soviet_merlin · Posted

      Thanks for doing that Duncan! Makes you a good person in my books. We don't get kangaroos or wombats here. But we have bats and it's similar. AFAIK it's often the mums with a baby attached that get hit because they drop lower when starting from a tree. If you hit an animal, check on it. https://www.ifaw.org/au/resources/wildlife-rescue-app An app to get the closest wildlife rescue contact.
    • Murray_Calavera
      Jacks that fit under GTR lips that can reach the subframe?

      By Murray_Calavera · Posted

      My dream is also to have a proper hoist, but I don't think it will ever happen. My quickjack is probably as close as I'll ever get, it really is very good though. 
    • Duncan
      Duncan's V37.......race car?

      By Duncan · Posted

      Yeah we keep on in the dailies, it is pretty poor how many animals get hit and the driver leaves without checking....have saved a couple of little ones over the years. Bit of a gruesome job though, pouches generally need to be cut open because they are so tight and often the joey doesn't realise mum is gone so they are still locked onto the teat. I checked the modules in front of the DS wheel where an oil cooler should go.... There is the radar unit - that can go for race use) One of the 2 HX water pumps, the silver cylinder. That needs to be kept but might be able to be relocated But the bad news, the big computer mounted vertically in front of the wheel (blocking any potential air exit) is the electric steering computer. That is required until/unless i do a hydraulic steering conversion, and in CAD based modern car design it is not like I can just pop a big unit like that somewhere else (plus the loom would be too short anywhere else too). So, the passenger side is OK to clear out (just use a smaller washer reservoir, potentially elsewhere), but the DS no beuno
    • Duncan
      Chris' Toyota Mark ii JZX110

      By Duncan · Posted

      Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
×
×
  • Create New...