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At what point do you delete DI injectors?

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I have a Huracan making 1600hp currently. I am just trying to figure out when I should, if ever, delete my DI injectors or if I can just keep going bigger on the port injectors? My car is currently controlled by stock ECU's and I have a 3rd set of injectors controlled by Motec. I have purchased the real Huracan Motec kit that replaces the stock ECU's but I have not installed it as of yet. I am trying to decide if I should run all 3 Motecs with the DI and the dual port injectors or consider deleting the DI injectors and just running both port injectors with the 2 Motecs.

This, DI or port, has been discussed in other threads - IIRC, the recommendation is to continue using the DI as the fuel is important to prevent overheating/melting the tips.

Best option may be to use the DI for normal, off-boost, fuelling, then when approaching their limits, drop them back to, say, 90% duty for cooling, and suppliment with the ports system(s).


I would actually remove the injectors and use a block off kit that T1 has to physically delete them. Honestly I wouldn't mind keeping them as I will have control of all 3 of my injectors. I just dont want to risk damaging my engine. It always weirds me out how you are injecting half your mixture with the port injectors so you essentially have a lean mixture until the DI injectors come into play during the compression stroke. I didnt know if that lean initial mix could cause pre ignition or not under 2k plus HP levels.

Your running some very serious power.. 1600hp.. 😳

My experience with DI injectors is at the 400hp level with only 1600cc and a turbo, but I think it’s still relevant.

Use both, that’s my plan it’s what the OEM’s do.

Motec should give you the ability the blend the DI and port.

Do you have access to larger DI injectors and DI Pumps.

ExtremeDI do some good stuff. I’m planning to add port to my setup, to take some load of the DI system.

I'd say DI injectors should stay as combustion chamber cooling feature which is even more important at such a high power level where even a small difference in temperatures can have very huge impact on final outcome...

Wouldn't port injection have more time to cool the air charge? I wonder why the high HP cars end up deleting it then?

One of the DI advantages is that it gets better fuel atomisation and better cooling effect as the fuel immediately evaporates when injected into combustion chamber. That combination allows to have higher CR or ignition timing which provides more power...


Lots of folks run 80-100% injector duty with port only, so they aren't getting their fuel into the cylinder all at once either.

The port injected fuel has more time to cool the air charge outside the cylinder, but I believe the in cylinder cooling DI offers with relatively early SOI and very high injection pressure is still useful.

DI injection is really precise and has great atomization which is helpful when cold starting ethanol fuel if you're running it.

When it comes to big power cars, removing things for the sake of weight reduction, simplicity, improved access to items, quicker engine remove/reinstall sometimes trumps what's ideal for engine operation.

In the meantime, just remember to keep the DI injectors spraying under load so they don't get damaged.

Quite often the only reason why big HP builds have the DI removed is that the ECU that is being used to control the engine doesn't have support for DI.

DI can also increase the dynamic CR of the engine when the fuel is injected with the valves closed.

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