Turbo: After market custom installs

[Turbo Kitty]

My turbo system is an after market, 100% custom install. This tends to limit the number of people that I can exchange info with because the great majority of turbo enthusiasts, anywhere, belong to some given OEM "family". It's either the factory Mitsu's, or the Subaru's, or Dodge's, or the Nissan's, Supra's, etc., but rarely a "new-born", after market "creation".

My Turbo Kitty was not born blown; we converted it.
The car is a 1994 Jaguar XJS with a 4.0L straight 6, with ported head.

A T04E with ceramic bearings and internal wastegate is at the heart of the system. Because we went with no intercooler and because the 9.5:1 compression ratio was not altered, the boost was capped at 8 PSI. In place of the IC we installed a boost-dependent water methanol injection system and, just in case we also installed an MSD spark retard controller. Fuel delivery remained OEM, including the injectors, but for the boosted segment two extra injectors were added and controlled from a Split Second extra injectors controller.

The car also features nitrous injection, which nowadays is only used to eliminate any possible turbo lag via 60 HP jets and a 3 PSI Hobbs kill switch; or, it has a driver-controlled switch to keep it going "as necessary..."

One of the problems with this situation is that turbo, dyno or tuning shops only cater to guaranteed-volume systems, such as the ones listed above. You go custom and their turbo know-how quickly becomes questionable. In fact, I can sure use some tips or recommendations of this kind, within So. California

So, this is why I'd like to know if there is anybody in this Forum who owns a custom and/or after market turbo install. I can sure use other's experiences, or share my own.

Hope to hear something,
Regards

[Turbo Kitty]

Just a bit of info that I left out.
I also own a supercharged 4.0L Jaguar; it's an XJR.
This gives me great means to compare turbos vs. superchargers and to put in perspective performance improvements and tweaks that I carry on my turbo kitty.

[ebxr8240]

I guess the system would be close to the 4.0 Ford six here in Aussie..
We fit GT45/40 or T04Z to the sohc engines.. Ford a few years back bought out the XR6T 4.0 which is twin cam and 24 valve engine..Long stroke of nearly 4"..
These engines through Nizpro have made over 1000 h.p at the fly...
Click on dyno runs...
Browser Warning
Dyno http://us1.webpublications.com.au/st...0hp-engine.avi
The std engine has 270 kw....362 h.p in std form...Through T5/6 tremech or 6 speed ZF auto...

[Turbo Kitty]

Ipressive run, mate

[skipster04]

What kind of information are you looking for? My car started life as a 1.8l none turbo and is now 2.0l turbo... all done by me in the driveway and tuned on the street with an innovate LC-1 wideband and the trusty butt dyno.... how are you controlling the fuel to the engine? do you have a stand alone fuel management or have you alterd the stock ecu? and it sounds like to me you just need to find a dyno that knows what they are doing. also what brand turbo are you running and what are the specs, and if its chinese that fine thats gat i've run reliably for 2 years now.

[Turbo Kitty]

Like I stated on a previous post, my fuel delivery below boost is 100% stock with zero alterations. At boost, two additional injectors (right before the throttle) provide the extra fuel and are controlled from a Split Second "Extra injector controller". Another Split Second item is a voltage clamp at the mass airflow meter so the ECU never sees "above stock" airflow. Right now I only have water methanol injection (Snow Performance) to cool down the charge, but we're working on a custom intercooler setup. I recently got my (internal) wastegate ported and resized because of substantial boost creep. Have a Turbonetics BOV, MSD spark retard with cockpit control and a manual boost controller made in Aussie land. Also have cockpit mounted AEM wideband AFR gauge, AutoMeter boost, fuel pressure and intake air temp gauges.

I see boost building up to about 7 to 8 PSI but I'm not that impressed with the power it is making. I own a V8 XJR for reference and there's just no comparison in power. My AFR at full throttle is between 11.8 and 12 with the W/M starting to shoot at about 5 PSI. If I keep my foot on the floor, it still wants to creep up to 10 PSI, problem is that when it shifts (auto) the boost must be spiking because it back fires (loud caugh from underneath). I'm failing to determine what is limiting the power that appears to be missing. Maybe I need to shell out $700.00 and get a pro tune (again)? Last time the tuner could not make power and gave up, but still cost me $700.00. (turns out that I had a plugged catalyst) "Don't know the car enough to know why I'm not getting power", he said. The only thing I have not done myself is to alter the fuel map with my laptop. I think that the AFR indicated is fine and I wouldn't know where and why to start altering it.

What do you think, mate?

[skipster04]

the backfire would be from being a bit on the rich side and that could also explain the power issues. If you had a plugged cat when you first tuned and you've since had that fixed that would change everything compleatly especially if you used the wideband that goes in the exhaust that dyno's usially have. also do you have a wideband o2 sensor in your exhaust before your cat? the fuel map is what is going to change your a/f. do they require emissions testing where your at because if not, take that thing out, it will make your turbo spool much faster without the back pressure it creates. also $700 for a tune?! wow you need to find a differnt shop.

[Turbo Kitty]

I think you may be right. It could be that the W/M injection is contributing to the rich condition. Perhaps I should re-tune it to about 12.5:1 WOT WITH the W/M spraying and see what happens. And yes, I do have a wideband AFR gauge in the cockpit and the sensor is located before the cat. Regarding the cat, I do have to keep it to pass emissions, but I believe that with the new cat the flow improved a lot, in fact so much that the turbo started seriously creeping up. We had to cut a much bigger hole in the internal wastegate to keep it "quiet".

Yeah, $700.00 for a tune and I don't think that I can find a cheaper one, not here in So Cal, anyways. So, I must deal with the fact that I just need to dive in and begin to do some tuning work on my own. I can learn a lot in doing so, and I'll eventually have full control of what happens with my system. I have read several articles that suggest that tuning can be achieved without necessarily using a dyno, but rather driving/testing/re-adjusting over and over, provided that you have the pertinent software, a laptop with the necessary interface, a wideband AFR gauge and an accurate boost gauge on board. I have all. I'll keep you posted.

Thanks for the input, mate.
Ever heard of Grange Hermitage?

[ebxr8240]

You need an ECU that reads boost..
Check EMS Stinger ,Haltech E6X,
Microtech ecu's but in your case run it as piggy back..
Fore engine fuel and timing only.. Leave std ecu for idle control, auto etc..

[Turbo Kitty]

Do you mean in addition to the Split Second Extra Injector Controller that I mentioned above? It is a boost-dependant mini-ECU and it can be tuned with a laptop. We installed that because we chose not to go with after market injectors and the OEM injectors started acting funny when we increased the fuel pressure to them.