More displacement and better tuning fixes that issue. I mean sure you still have to spool the turbo and all but lag eh you can tune around that. When I get my pos back together again I'll show you lol. I think it all comes down what rpm you decide to boost your turbo at as well. I eman if you think your going to start your spool at liek 2k well then yeah that would be turbo lag. But if your starting spool at like 4k when your in the powerband it tends to go away pretty quick.

 

​​​​​​I Don't drive around much at 4-8+k RPM so I'd definitely be bored.
I can floor the gas from a roll and spin my cheapy tires across the intersection.

 

Lol then you get the idiots "do a burn out" lol

 

That's funny because I HAVE had people say that. I don't even know how to reply to them.

 

I just put together a 9:1 2.0L with a Boostlab 67x for my Evo 8. Having closed loop boost control, closed loop fueling, emap for expansion ratio, and full flexfuel capability with running an Emtron KV8 standalone and 12 tooth Kiggly crank trigger the combo should be able to make 900whp reliably on E85-90.

 

Will higher compression spool turbo faster? My current setup with 10.5 compression is around 5-6 full boost depending what gear. I know stm using 11.5 compression on their high hp builds 🤷‍♂️

 

No, higher compression won't spool the turbo faster.

Read this article it explains Compression and Boost really well
https://dsportmag.com/the-tech/boost...sion-benefits/

 

Great article thanks a lot!! But I still did not decided what compression ratio should I build. I dont want the car be slow off boost because even on my old engine 10.5:1 compression the car is slow off boost and I dont want to be even slower. On my gsc s3 cams feel like a turtle until I hit 4500rpm or higher. To my understanding same setup but lower compression will make the car even slower ( less torque ) off boost so in my case anything below 4500 rpms

 

Slow off boost is related to cam timing, with the Evo 8 being non-mivec you will need to adjust cam timing to change how the power band lays out over the rpm's. Evo 8 you have to deal with trade-off with cam timing adjustments where as with an Evo 9 which has mivec you can spool a turbo so much faster because of the variable valve timing.

 

Cams are set to 0 and 0 . Should I advance them or retard or there is some other tricks to set them? Some time ago I spoke with the cams guru and he told me that gsc s3 cams works the best when set up 0 and 0 so I set them up this way.

 

@Ted B

 

Have you thought about dropping down to GSC S2's? Put some meat in the mid-range.

 

The GSC S3 cam has a long 238 degree duration @1mm with LCs at 108/116 and a resulting LSA of 112 degrees. This cam timing is excellent for what the cam is designed to do - deliver big power upstairs in drag racing applications. Predictably, it's going to be soft on the bottom, and is not going to spool an 800hp turbo on a 2.0L motor well on the street, particularly not in low gear with an open T3 turbine side. Advancing the intake cam 1 degree and retarding the exhaust cam 1 degree (+1/-1) will make the idle bumpier, but the resulting tighter LSA will shift mechanical efficiency toward the midrange, which should help nominally, albeit at the expense of a few hp on top. On the street however, that is a good trade.

In the interest of not hijacking this fun discussion regarding static compression ratio (SCR), we can reiterate that a higher SCR in this case improves torque nominally at off-boost speeds, where the engine is mechanically inefficient and in a state of a low dynamic compression due to the long cam timing. Raising the SCR however, does not help spool the turbo. If anything, increasing thermal efficiency (the effect of raising the SCR) points to the opposite direction.

 

Compression and boost really dont mix. A full point of compression is only a ~3% power gain in an NA application. Adding compression in a turbo application much past 9:1 just means you end up running less timing, and you get to point where it simply limits power.

Our cars make ~150wtq off boost on a GREAT day. I don't think the 6-7% (12ftlbs) gain from 9:1 to 11:1 SCR will be very noticable. It's much more important to select a camshaft and turbocharger that matches what you're trying to do.

 

How much SCR to run is one of those perpetual questions for which there is no one-size-fits-all answer, largely being a matter of available fuel octane with respect to a host of other variables. We should clarify that an engine on boost making 400hp and 400ft/lb @ 5252rpm should benefit from 12-20hp at that point with an equal bump in torque with an increase of one full point of SCR (fuel octane permitting and with appropriate tuning), so it does present nominal improvements in thermal efficiency (and fuel economy) across the board and under all operating conditions. This is why we see newer DI engines being engineered with SCRs that are impractical with our port injected predecessors.

Where fuel octane limitations begin to hamper our ability to achieve MBT (Mean Best Torque) ignition timing however, is the inflection point whereby the ignition retard necessary to avoid knock begins costing more power than is gained by the higher SCR. This isn't really a concern for the drag racing Honda K24s out there running 13:1 SCR and lots of boost on methanol, where there is a fine line between MBT tuning and destruction. More impressive to me were the BMW stock-block 1.5L turbo F1 engines of the 1980s, which had a 7.5:1 SCR and used a ton of boost to get 1200+hp for qualifying and 850hp for the actual race, all achieved on gasoline limited to 102 RON, which is ~97 AKI (US).