Max power with 92 octane pump gas, no E-blends

[PInimodulo]

Hello everyone,

I’m in the middle of my second (and probably last) round of upgrades on my 2020, and wanted to get some thoughts from people who’ve been through this.

Current setup:
AA catted downpipe
xMOD exhaust
MHD Stage 2
About to install:
Remnant Performance Omega 65 turbo
Gamma intake manifold

My goal is to get as close as possible to 600 WHP on straight pump gas (with torque at no more than 550 ft-lb to avoid tranny issues) No E blends, no meth. The downside is I’m stuck with 92 octane here in Seattle, so I know that limits things a bit. I read the GR Supra 101: Routes to big power by the way.
I talked to David Shoup’s team, and they mentioned I’ll need at least S58 injectors and ideally an upgraded HPFP. Even with that, they said I might not even hit 550 WHP, which was a bit sad.
So now I’m wondering, I know cams usually aren’t needed unless you’re pushing way higher power, and I know it’s a bigger job, but do you think a performance cam could help close that gap a bit? Maybe squeeze out an extra 30–40 WHP while staying on pump gas? Also, I kind of like the idea of raising the RPM limit as much as safely possible and shifting the powerband a bit higher, which could help reduce tire slip and maybe ease some stress on the transmission at the same time.
Not sure I’ll go that route yet since it depends on budget, but figured I’d ask before I rule it out.
Would love to hear what you guys think or if anyone’s tried something similar on pump gas.
Thanks a lot for any insights!

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[Hammerhead13579]

I posted something similar to this last year about getting 500whp on 91 octane with a small hybrid. Everyone just talked shit and said I need to read up more about how to make power and/or just use ethanol.
Anyway, that's when I thought I didn't have access to any Ethanol. But just because the closest pump around me and you is in Snoqualmie doesn't mean you can't get ethanol - I just got 2 VP racing jugs full of E98 from a shop at Pacific Raceways. You can get barrels from them too and they deliver.

So instead of trying to get "cute" with your build - just accept that you will make less power on "91" (our 92 really isn't any better) or get some E like everyone always says. Let me know if you want more info on the shop.

 

[Evolution]

I talked to David Shoup’s team, and they mentioned I’ll need at least S58 injectors and ideally an upgraded HPFP. Even with that, they said I might not even hit 550 WHP, which was a bit sad.

tons of people are doing 500whp on e40 with stock fuel system. If you upgrade the injectors and hpfp, your goal is more than easy on pump gas, fueling wise.

 

[PInimodulo]

Yes, fueling wise but still needing E blends that as I stated I want to avoid.

 

[Evolution]

Yes, fueling wise but still needing E blends that as I stated I want to avoid.

I was just stating that if people can make 500whp on e40 and a stock fuel system, you can make 600whp on pump gas with a hpfp and injector upgrade no problem. How you get to that power level on pump is your problem and I have no comment there. Again, previous comment was towards fueling only since what I quoted was confusing on if you were questioning if you were limited to octane or fuel demand.

 

[i3igpete]

A 900-hp rated turbo will get you to 600whp on pump gas, but there are some caveats.

Ideally, you'd want to pick the compressor wheel thats at peak efficiency very near redline. The omega 65 fits the bill on the compressor side, but the "hybrid-like" design (big compressor, small turbine) is great for low end spool chokes the exhaust side of the cylinder head at the high rpm. Note that the definition of hybrid here is the old-school one, such as "t3/t4" or "td04/td05". Not the bmw definition of hybrid meaning "stock housing, upgraded wheels" .

You need to pick a turbine wheel that is significantly larger than the compressor. Less exhaust manifold pressure allows better voleff. Additionally, a top mount's runner volume allows some buffer for exhaust pulses to queue up. This is where the precision 6466 or garrett g35-900 come in. These are working against you on the omega 65. This smaller turbine wheel and the stock-like runner volume mean that it's great for spool and brute forcing power with PSI. This is all bad for airflow to completely empty the cylinders and keeping the head cool, when you're trying to make power with knock-limited pump gas.

The net effect is that for pump gas you want to right-shift the powerband as much as possible, to make all conditions "just right" at the same time to avoid knock and get the most mass flow for the given manifold pressure.

 

[licklobster]

Meth tank and injector would skip the E and negate the need for bigger injectors and easily put you past 600, but it would be a constant maintenance/fill thing.

The stock heads dont flow well enough to benefit much from cams at rpm limits a stock engine will live at, + the extraordinary expense of cams kind of rules that out as practical for this type of setting. You only really need cams (or engine porting) when you want to extend your rpm range.

 

[PInimodulo]

I was just stating that if people can make 500whp on e40 and a stock fuel system, you can make 600whp on pump gas with a hpfp and injector upgrade no problem. How you get to that power level on pump is your problem and I have no comment there. Again, previous comment was towards fueling only since what I quoted was confusing on if you were questioning if you were limited to octane or fuel demand.

Thanks for your response and explanation Sean, I am sorry if I sounded mad, it was not my intention. And yes, fueling wise I should be more than set for that level, but we need to find the right combination/way to make it that high.

 

[PInimodulo]

A 900-hp rated turbo will get you to 600whp on pump gas, but there are some caveats.

Ideally, you'd want to pick the compressor wheel thats at peak efficiency very near redline. The omega 65 fits the bill on the compressor side, but the "hybrid-like" design (big compressor, small turbine) is great for low end spool chokes the exhaust side of the cylinder head at the high rpm. Note that the definition of hybrid here is the old-school one, such as "t3/t4" or "td04/td05". Not the bmw definition of hybrid meaning "stock housing, upgraded wheels" .

You need to pick a turbine wheel that is significantly larger than the compressor. Less exhaust manifold pressure allows better voleff. Additionally, a top mount's runner volume allows some buffer for exhaust pulses to queue up. This is where the precision 6466 or garrett g35-900 come in. These are working against you on the omega 65. This smaller turbine wheel and the stock-like runner volume mean that it's great for spool and brute forcing power with PSI. This is all bad for airflow to completely empty the cylinders and keeping the head cool, when you're trying to make power with knock-limited pump gas.

The net effect is that for pump gas you want to right-shift the powerband as much as possible, to make all conditions "just right" at the same time to avoid knock and get the most mass flow for the given manifold pressure.

Thanks! Yes, a bigger top mount would help, but I am not really inclined to do that, plus I already bought the Remnant one. With luck we will get it to perform good enough for my goals!

 

[PInimodulo]

Meth tank and injector would skip the E and negate the need for bigger injectors and easily put you past 600, but it would be a constant maintenance/fill thing.

The stock heads dont flow well enough to benefit much from cams at rpm limits a stock engine will live at, + the extraordinary expense of cams kind of rules that out as practical for this type of setting. You only really need cams (or engine porting) when you want to extend your rpm range.

Yes Chris, I would love all those things that the cam gives, like the extended RPM range and a shift of the powerband to a higher section of the RPM range.
I used to have a Datsun 240Z with cams and then a bridge ported RX7, and I love that high revving, higher RPM power kick feeling.
But yes, the price for that would make it pretty hard and to get the benefits I would have to do some porting, polishing of the head and maybe even the valves, which would be awesome to do, but I dont thing I have the time.

 

[i3igpete]

As great as the BMW valvetronic system is, the aftermarket companies still haven't caught up. That's why aftermarket cams on this engine typically only get you a half mm more Maxlift.

The intermediate lever is the limiting factor, and as far as I know, nobody makes a replacement. If you stick on a cam with too much lift, you essentially just run off the tip of the intermediate lever. You need to upgrade both the main cam and intermediate lever (a.k.a. SwingCam) to truly get higher lift. Then the torsional spring (which also has no aftermarket replacement).

 

[PInimodulo]

As great as the BMW valvetronic system is, the aftermarket companies still haven't caught up. That's why aftermarket cams on this engine typically only get you a half mm more Maxlift.

The intermediate lever is the limiting factor, and as far as I know, nobody makes a replacement. If you stick on a cam with too much lift, you essentially just run off the tip of the intermediate lever. You need to upgrade both the main cam and intermediate lever (a.k.a. SwingCam) to truly get higher lift. Then the torsional spring (which also has no aftermarket replacement).

Interesting! Thanks for the explanation!

 

[razorlab]

Having a 2020 with higher compression is not going to do you any favors chasing power with pump gas.

 

[PInimodulo]

Having a 2020 with higher compression is not going to do you any favors chasing power with pump gas.

Yeah, definitely. We will see how far we can push it safely.

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