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View Full Version : Using water injection instead of an intercooler?


keithmac
11-03-2005, 10:44 PM
Hello, just bumped into this forum and having a look around.

I`m currently supercharging a VW Golf mk2 16 and looking into the possiblity of using water injection instead of an intercooler.

Looking to run approx 1 bar of boost on UK 98 ron fuel, maybe going a bit higher if this proves reliable.

I`m in a rush tonight but will be back on tomorrow, if this topic has been covered many times then do accept my oppologies :oops:

Any links to old topics on this subject or comments would be apreciated.

Cheers, Keith.

Richard L
16-03-2005, 03:32 PM
Most Jackson Racing Miatas (MX5) are supercharged without intercooler, they just supply a water injection system, works very well.

keithmac
16-03-2005, 09:28 PM
Yeh I`ve been having a bit of a dig about and it does seem a good solution seen as most of the time it`ll be driven off boost anyway.

I was looking at the Aquamist 1s, just a boost switch to come on at 5 psi, seems a good starting point.

I`ll be using a washer bottle in the boot with de-mineralised water (don`t want a false afr reading), take it the VW screenwash pump will be up to the job for priming?

JohnA
20-03-2005, 08:00 AM
...
Looking to run approx 1 bar of boost on UK 98 ron fuel, maybe going a bit higher if this proves reliable. ....

98 RON fuel has stopped being available in the UK years ago mate. (at the pumps, because racing fuel can be had elsewhere ofcourse)

97RON is the maximum you can get from Super Unleaded, and 95 from regular unleaded, supermarkets, optimax etc (just as the pump labels claim)

(Wild guess here :lol: but don't be deceived by Shell's bull insinuations that optimax is 98+, it is only rated as 95.
Yesterday for example my knock sensor went crazy, and the tank was full of optimax. It doesn't do that even on BP standard!
Very incosistent fuel, and marketed misleadingly too)

ubcnme
22-03-2005, 08:58 AM
Hi I use my water injection as an intercooler. I four .3mm aquamist jets and 4 inline check valves with it. I get good results No detonation at all Im running 15 psi. you can check out my install on this forum. :smile:

keithmac
23-03-2005, 10:31 PM
Cheers for the input, I always use Optimax, car used to be on k-jet and pinked on 95ron fuel but not Optimax. I`ve heard some garages `cutting` it wit normal unleaded and other people say it can go off (full of aditived to bump the octane up).

May have to try BP Ultima if I get knocks?

ubcnme interested to here you run 4 jets, will have to have a good look at your install, my idea was to run the water directly after the charger to give it the longest run with the air to aid chargecooling (also from charger to throttlebody is just over a foot long, air temp sensor will be just before the TB) I take it yours are after the air temp sensor and nearly a direct port system? I can see how this will prevent knock but not really aid chargcooling?


Still new to all this so if I`m talking a load of balls please tell me :D

Nice to here some people having go results without an i/c over 90% of people I mention water injection to seem to dismiss it as too complictated or prone to failure which gets quite annoying..

Richard L
23-03-2005, 10:56 PM
If you have a choice of using an intercooler, it is the best solution. Not every car uses intercooler especially supercharged ones.

Due to the high vacuum in the inlet tract, it is not always possible to fit an remote (not bolted onto the engine) intercooler unless solid induction pipe is used.

For big power application, the intercooler can be restrictive - a car has only a certain amount of frontal area - 1000 bhp engine requires 10 times the frontal area n- unfortunately the car doesn't get any bigger proportional to power.

Lysander
28-03-2005, 02:41 PM
Unfortunately my car was not available with an intercooler, and aftermarket kits are well over 1,000 USD. So WI it is :cool: I'll let you know how it goes after dyno tuning in April.

bripab007
11-04-2005, 07:24 PM
Most Jackson Racing Miatas (MX5) are supercharged without intercooler, they just supply a water injection system, works very well.

Actually, I'm not aware of any Jackson Racing-supplied water injection kits for the their M45, Miata supercharger kit. They do offer a water-to-air intercooler upgrade kit, but that is not necessary on the base kit's ~6psi. Some timing is retarded on the kit in stock form as well. I guess the question would then be whether to inject before or after the 'charger...or both?

Slump
11-04-2005, 08:42 PM
Most Jackson Racing Miatas (MX5) are supercharged without intercooler, they just supply a water injection system, works very well.

Actually, I'm not aware of any Jackson Racing-supplied water injection kits for the their M45, Miata supercharger kit.

http://www.jacksonracing.com/Shop/ViewProducts.aspx?PlateIndexID=38405

keithmac
22-04-2005, 07:05 PM
Right got hold of an ERL race pump which I`ll be stripping and recondtioning hopefully. Decided to got water injection only, although I now have the problem of going pre or post G-charger, would thrmal shock to the casings or bearings be an issue? Think it`s magnesium casings?

keithmac
01-11-2005, 08:30 PM
Just digging this one back up :smile:

I`ve been running 10psi with my 350cc fuel injectors at 100%dc using a 0.8mm water jet on an earl race pump and it behaved fine, no knocking and 45c MAT with no intercooler.

Upgraded the S/Charger pulley and I`m now at 1 bar boost, running 500cc injectors at 80%DC, MAT`s over 50c so I`m going to try a bigger jet(s) first, if that doesn`t bring the MAT down enough I`ll be into intercooler teritory.

Just off to dig out the flow vs jet size graph on here..