Dermot style question.....

[Evil_Dr_Fish]

Hi guys.... (particularly Dermot?! )

I just wanted to get opinions on how far you (in a 'devoid of all liability', 'non legally binding' sense) reckon you can push the boost before you really ought to have some form of inlet cooling (albeit C.C or W.I - that's a whole other thread!)

I have changed those nasty old iron pistons for the Nikasil process ones etc so they're not an issue... in theory, the lump itself should be good for over 300bhp. The Maserati / Citroen gearbox we estimated would be good for 250-260 bhp? (any other opinions?) That's by going on Lotus assuming approximately a 15% leeway in their components and they pushed the HC car to 215bhp.

It's (I guess) all just a question of inlet temperature / pre-ignition?

Are there other factors?

Cheers,

Robin

[Dermot]

Robin,

There are a number of issues. Engine knock will loom very quickly and that is a real engine breaker if you do not have knock sensor. When knock occurs is complicated to predict, for example it is related to fuel quality, A/F ratio, inlet temp and your engine.

As you up the boost you will start to go outside the maximum efficency window of the turbo compressor map, inlet temps will rise and you can get thermal run away very easily.

There is even a senario in which increasing the boost lowers your overall power output. Just based on an air density model 1 dec C increase will lose you approx .5 hp.

I don't know what boost you are running at the moment, I would take it up .1 bar at a time, at the same time get some carful dyno work done. You also need to worry about your fueling.

Dermot

[Evil_Dr_Fish]

Hmm.. ok - sounds like there's potentially a lot more to it than I thought!

Currently it's just at a stock 0.55 bar (I think taht's correct)

We were thinking of adding a bleed valve and taking it up to 0.8 - 0.9 bar (max)

I guessed fuelling would need to be 'upped' or at least adjusted in some way in order to add an appropriate ammount of combustible 'material' to all that densely packed oxygen....

I appreciate that knock can occur anywhere depending on teh individual set up (as you say...) but surely that turbo situation (losing power) would be more at the extremes than just upping it by about 0.2 - 0.3 bar?

Or am I really not understanding the physics here?!

[Dermot]

Robin,

Be careful with bleed valves, can are prone to giving boost spikes.

You are running fairl modest bosot at .55 bar, I would suspect that 0.2 -0.3 increase should be OK, if you fuel it up to compensate that has a slight cooling and anti-knock effect as well.

Fit a proper accurate boost gauge.

D.

Hmm.. ok - sounds like there's potentially a lot more to it than I thought!

Currently it's just at a stock 0.55 bar (I think taht's correct)

We were thinking of adding a bleed valve and taking it up to 0.8 - 0.9 bar (max)

I guessed fuelling would need to be 'upped' or at least adjusted in some way in order to add an appropriate ammount of combustible 'material' to all that densely packed oxygen....

I appreciate that knock can occur anywhere depending on teh individual set up (as you say...) but surely that turbo situation (losing power) would be more at the extremes than just upping it by about 0.2 - 0.3 bar?

Or am I really not understanding the physics here?!

<{POST_SNAPBACK}>

[Evil_Dr_Fish]

Thanks for that Dermot

[Evil_Dr_Fish]

Thinking about it some more... Would fitting a Boost Controller similar to yours be better than a bleed valve?

It would also fulfill the "Accurate Gauge" role and give me high and low power modes....

[MrDangerUS]

Robin,

I'm really glad that you started working on your (orphaned for a while - LOL) Esprit!

You won't be able to run more than 10psig, because the overboost module will cut off the pumps. 10 psig for CIS Jetro Esprits is a max.

I am replacing my previously added AEM-1 boost controller with Innovate SCG-1 (AFR+boost controller+duty cycle+gauge=all in one)
http://www.innovatemotorsports.com/products/scg1.php

Very neat gadget, which also gives a data logging capabilities (you'll need to buy Innovate PL-1 data logger).
The Innovate Motorsports SCG-1 is a revolutionary approach to boost control that integrates an advanced standalone boost controller with Innovate’s industry leading DirectDigital™ wideband air fuel ratio technology. When we decided to build a boost controller, we knew we had to offer more capabilities than other products available today, while still maintaining the user friendly functionality demanded by our customers. Instead of repackaging the same boost control technology that has been used for decades, we choose to pair our advanced O² sensor control technology with our all-new, proprietary solenoid control that provides superior boost control accuracy, response and safety. We also added a user programmable shift light and housed the entire package in a compact gauge body for ease of installation and use. As with all of our air/fuel ratio products, the SCG-1 utilizes the only 100% digital wideband air/fuel ratio technology to provide real time feedback to the SCG-1. This air/fuel information is displayed on an integrated OLED display along with manifold pressure and wastegate duty status. The air/fuel ratio information is also used to provide a user definable boost cut that enhances the safety margin over most competitors offerings that only rely on over boost threshold. The SCG-1 has a full-programmable analog output ideal for applications using standalone ECU’s, piggy-back ECU’s or external data loggers. The SCG-1 also has a digital input/output for integration with our other Modular Tuning System (MTS) devices. This same digital output can be used to record air/fuel ratio, solenoid duty cycle, engine speed and manifold pressure with our free LogWorks PC software to help you dial in a perfect boost curve.

All-in-one, intelligent boost control and wideband air/fuel ratio gauge
Controller and display housed in 52mm (2 1/6”) diameter gauge body
Interchangeable face plates & bezels: Black & silver bezel, black & white face plates included
No PC required for configuration
OLED user configurable display
Boost, shift light, Air/Fuel ratio
AFR or Lambda, inHG, PSI, kPa, or BAR
Includes high resolution solenoid
4 BAR map sensor, pressure range -29 inHG to 43.5 PSI (-1 to 3 BAR)
User programmable boost cut safety using Air/Fuel and Pressure references
Programmable solenoid duty cycle with separate gain control function
Peak hold function
Patented DirectDigital™ wideband sensor control, the only 100% digital wideband air/fuel ratio technology!
Wideband O² Compatible with several fuel types (Leaded, Unleaded, Diesel, E85 & more)
Ability to calibrate O² sensor for maximum accuracy
Configurable linear 0-5v analog output for wideband O² for use with piggy back or stand alone ECU’s as well as external data loggers
Innovate MTS serial in/out (for use with other Innovate & 3rd party MTS enabled devices to add additional logging channels)
4 channels of log-able data with powerful LogWorks PC Software (MAP, RPM, A/F, WG duty)
.

Edited June 25, 2016 by MrDangerUS

[MrDangerUS]

On 3/26/2005 at 13:58, Evil_Dr_Fish said:

Hi guys.... (particularly Dermot?! )

I just wanted to get opinions on how far you (in a 'devoid of all liability', 'non legally binding' sense) reckon you can push the boost before you really ought to have some form of inlet cooling (albeit C.C or W.I - that's a whole other thread!)

Robin

Pre 89 cars have absolutely NO anti-knock sensing processor. You have to add your own!

All pre-89' Turbos are missing several key engine management systems, like reliable boost controller, ECU, electronic spark management and anti-knock protection.

Just Google this phrase "   1986-88 Bosch CIS K-Jetronic injected Esprit specific items " 

Consequences of not having the anti-knock countermeasures may be quite dire, see post #68 and #72 .

Crude anti-knock processor was implemented in 1989 MY, when Delco Engine Management system/ECU was introduced.
That is what I have installed on my car instead! For details, go there: J&S Vampire

On 84-88 Esprit turbos equipped with OE Lucas Hi-Energy Ignition, a single channel Vampire should work fine, but to be on the safe (modern) side, an upgrade to Pertronix Ignitor pick-up and Flame Thrower Coil would be a prudent precaution.

If one decides to graft-in a Megajolt-E and Ford EDIS (wasted spark, dual coil) ignition system, the Dual Channel processor is required. Megajolt/E | Autosport Labs

Normally, the Vampire is disabled below 1750 RPM, because Ford ECU fires triple spark(s) below this rpm threshold and confuses the processor.
Since you’ll be using Pertronix or Megajolt-E, the Vampire should be modified (specify your system configuration before ordering ) to enable detection at 1250 RPM and sensitivity should be amplified quite a bit for our engines . Parts needed: 8mm ID Bosch"doughnut" knock sensor and a 15 ft sensor cable, gauge with 5 ft cable; all included in the kit. John at J&S will take a good care of that.

In addition, one needs to make an aluminum “boss” with M8 threaded hole and epoxy it to the block between cyl 3 & 4, just above the oil sender unit, at the same location where the later SE car Delco ECU listens to the engine knock.

On 89+ cars, Delco ECU  anti knock (primitive) processor retards all cylinders upon detecting a knock in any one cylinder, therefore robbing the power from other cylinders!
The SafeGuard Vampire controls the timing of each individual cylinder in proportion to the degree of detonation occurring, thus maximizing performance and preventing engine damage.
Vampire has a dual mode switch and retards only the individual knocking suspect, or “retard all”. Also, it has a 2° and 4° Nitrous Retard setting/switch.
MSD coil PN 8241 can be safely used in place of the OEM EDIS coil with excellent results. Avoid any aftermarket "hi performance" coils which look like fluted factory chimney stacks (junk!).

Using a single knock sensor, Vampire detects the onset of detonation and retards the timing on a "per cylinder basis", up to a total of ten increments.
A mode switch lets you select a maximum of either ten degrees or twenty degrees of knock retard.
In the ten degree range, each increment is one degree; double that for the twenty degree range.

When knock is detected, software determines knock intensity and decides how many increments to retard this cylinder the next time it fires.
The software retards in proportion to the knock event, up to a maximum of seven steps with one knock event.

The system is always trying to re-advance to stock timing. In the ten degree mode, it re-advances at the rate of one degree every twenty revolutions; double that in the twenty degree mode.

The system does not need a cam or crankshaft reference sensor to determine which cylinder to retard. The unit is programmed to "know" that the knocking cylinder is the one that just fired, and that it won't fire again for two more revolutions. When the knocking cylinder comes around to fire again, software dials in the retard amount for that cylinder. It does this as each cylinder goes by, building up a different retard amount for each cylinder.
The detection algorithm employs a "knock window" to listen for knock at the appropriate time in the combustion cycle.
 

If you have any questions, please PM me at MrDangerUS@hotmail.com for private consultation. LOL

 

 

Edited June 25, 2016 by MrDangerUS

[Bibs]

11 year old topic mate, now locked.