E85 with stock VVT NB2
 

I'm lazy and don't want to search the details.

stock fuel system from a 99 (pump regulator, lines, etc) with a relatively stock NB2 VVT motor with NB2 VVT injectors some exhaust and intake upgrades. Assuming proper ECU tune for E85. Will the fuel system supply enough E85? or do I need upgrades there too?

it should

Yes.

So I guess there is at least a 30% margin of flow rate then on the stock setup.

log WOT and see what the maximum duty cycle you hit on the injectors?

I've got no experience with it, but I'm surprised to see you guys saying it'll be fine. I thought you'd need some injectors. In for results I guess.

https://www.miataturbo.net/engine-pe...jectors-86827/

https://www.miataturbo.net/engine-pe...e-gains-76251/

[NA] 135whp with stock NA8 long block - MX-5 Miata Forum

With the 60psi fuel system you should be fine.

^ Good stuff, I didn't realize how many people had done it. Looks like you can find some pretty solid gains too.

Plenty. Good for about 175whp N/A on corn. That's the primary reason the NB is the car to have in NASA PTE/TTE, uses fewer points. NA with less fuel pressure and lower flowing injectors only supports about 125~130whp on corn.

good to know. swapping in a full 99 fuel system into a 1990. VVT motor, VICS intake manifold, Racing beat Header, Fujitsubo cat back. Going to run Corn.

Because CSP car.

keep the parts coming.

Good setup. Play with VICS on/off all through the rev range. We found some nice gains with two switching points. NB2 injectors have a wee bit more capacity than NB1. SCCA legal built NB2 CSP motor can make about 168whp /140tq Djet SAE corrected on small tires, 225's. A tad less on 275's.

Yep got NB2 injectors and fuel rail came with the head we got. Had to die grind a bit on the manifold to get the NB2 fuel rail to fit with the VICS manifold. Might have got carried away on the die grinding and broke out the saws-all and the welder as I managed to whittle about 2 lbs of aluminum off of it including all the features related to EGR both inside and out LOL.

Car made 150 hp today on 92 pump gas. Then swapped to E85 which was more like E78. Fiddled with timing and fuel ofsett tuning for corn. Car made almost no more power on corn maybe 3 ft-lbs in the mid range max Actually Lost power with more timing than we were using for pump and was hitting 100% duty cycle at about 5800 rpm.

what were the afr's on e85?

Something is off. Even if you reach MBT on gas, there is still 4-5% on corn. If you don't reach MBT, the gains are often closer to 7%. What is fuel offset? Injection timing? No need on a NB that is port injected with small injectors. Just make sure injection timing is phased with VVT in your software.
You can just input -360° and it won't care unless you have big cams and lots overlap.
Safe gas tune is 12.8 near peak torque tapering to 13.0 at high rpm when VE drops off. Corn can run a tad richer, Lambda corrected to effective 12.5~12.8.
How much timing on top? Gas on an stock cam NB2 is usually about 32° =/- 2°. E85 I have seen stock cam NB1's and 2 keep making more torque/power until 38-40°

Afr on corn was going to 15 with injectors at 100% duty. We were not making more power with more timing mid range corn or gas. up top gas we were up to 26-28 but more timing didnt make more power.

Not unhappy with 150 on pump gas. Pretty strong for a stock motor. Fairly confident though our 99 fuel susten with stock 2002 injectors does not have capacity for jump to E85. Also based on the gains we were able to get at lower rpm tuning for E85. I think of we had enough injector E85 might only gain 5 ~10 hp. If we are lucky. Maybe its that North West pump gas is actually pretty good already. I know my beast won' t run for shit on anything out of a pump in California.

Were you making more power with E85 than with pump gas at ~5500rpm?

We are making over 130wtq and 150whp with e78 at 90% injector duty cycle on 01 injectors that were cleaned before install and a regulator from a NB at the rail. It made about +7 tq and hp at the wheels on corn. AFR's in the low to mid 13's seemed best as measured on the cars wbo2. This is uncorrected to uncorrected comparison on same dyno. The engine ecu was changed between the switch to corn so that may have had an impact and I suspect it did.

Your post was a bit misleading. It sounded like your afr's were correct and you did not make power but clearly you completely ran out of injector so you don't know if the corn would make more power or not. NB FPR on stock NB2 has just enough headroom for E85. We find it varies from car to car. Out of probably 8 cars we have set up like that, two ran out of injector. NB1 is more likely to run out of injector then in be too because of cams and slightly smaller injector.

This sounds about right. We got very little gains in the rpm range before running out of injector by getting the Afr diled in for E85. Timing wise if we ran either more or less timing than we optimized for gas it made less power. It wanted the same exact timing. The gains were small though under 5 hp/ tq in that range almost in the noise of run to run dyno variation.

Because of the very small difference it looked like was going to make we aborted throwing more money at it tring to source bigger injectors while it was on the dyno swap them out and spend another day tuning.

It has NB 1 fuel system pump, regulator, lines, fuel, rail. But has NB2 injectors.

I'll be going to bigger injectors soon to find out if e98 will make any more power and of course just to have some headroom as 90% dc is just too much.

I also would like to do a CSP engine build after Nats. I told myself I have to be somewhat competitive as the extra power won't do any good if I'm 3 seconds back. Then we'll see how close I can get to Emilio's estimate of 168/140. Or is that from first-hand knowledge?

I presume you mean NA6, since NA8's can make that much on 93e10 :p. When I tired to tune for e85 I hit max duty cycle around 5000rpm's on my 97. AFR's would hangout around 12.8-13, but obviously the fuel was just pooling and it didn't feel right in the upper RPM's WOT. An already not smooth revving motor felt even more trucky.

Thought Id update this. after switching to Deatschwerks 450cc injectors and spending more time fine tuning both for 92-pump and E85 the E85 was good for about a 7 hp gain and with across the range gains everywhere. ~157 hp 143 ft-lbs blue is E85 red is 92pump.

Please allow my to junk up this thread for a second. On a 95 with a VVT swap, could I replicate these results with the addition of a 99+ fuel pump? The motor with have a 99-00 fuel rail and NB2 injectors - at that point is the only missing piece a newer fuel pump, or are my factory lines an issue?

Its an NB2 VVT motor rebuilt with factory overbore and head shaved to minimum spec, with NB1 fuel system lines rail dampers regulator and all. added flex fuel sensor. 450cc injectors. Modified NB1 intake manifold with functioning VICS. few other secret sauce things that are all legal for the class.

Sorry, I guess I wasn't referring so much to the numbers but to the notion that the NB1/2 fuel lines were an integral part of the "E85 on a 'stock' fuel system formula."

Lines are fine, pressure @ injectors is different. USDM NB1/2 is 60psi non-reference. NA is 43.5 referenced. So, NB2 injectors + some way to run 60psi fuel system at WOT = probably G2G.

One of these kits:
https://supermiata.com/Walbro-190LPH-HP-Fuel-Pump.aspx

And an external adjustable fuel pressure regulator (Turbosmart actually makes a really good unit) and you can hit pretty much any power that a reasonable N/A Miata engine is capable of.

We were seeing 92% dc on a stock junkyard un-opened VVT engine on ~E80. That engine was making 132wtq, 155whp. That was with a factory pump, lines and rail from a 95 and regulator and injectors from a NB.