Author Topic: old 1.5 diesel power questions (Read 3915 times)

gldgti · « **on:** October 02, 2004, 04:50:05 pm »

HI everyone,
Im new here, but i've been reading lots of posts for a couple of weeks, so not entirely unaquainted...

my question refers to my '79 GLD. I've just done a new head gasket and rings swap to her earlier this week, and she's driving nicely. I understand most of you guys are running 1.9 or 1.6's, but noone with the old 1.5's it seems.

anyway, I'm just really wanting to know if there is much i can do to get a little more power/economy without spending any money (relatively speaking).

I fitted a 2" custom exhaust system to her last year, which has her breathing a little easier, and I have read up on the dynamic injector pump timing - which i'll do tomorrow. I have a custom grille and am plannign on fabricating a nice 3" or so pipe with a big ram type intake next to the radiator, which wil get me lots of nice cool air. Ive changed the injector pump adjustment to give me more fuel (further travel on the throttle lever) too.

so, is there much else i can do?

Ive already fabricated a custom lower stress bar to help in not having to accellerate - and it works really well to - she's cornering like a dream!

thanks guys!

oh yeah - i use bio-diesel too

pics of my car at http://scramjetsite.8m.com

RAMMSTEIN · « **Reply #1 on:** October 02, 2004, 05:18:49 pm »

Hi there!

Welcome on board!

1.5 and 1.6 Normally aspirated (NA) diesels can't be much tuned.

So you did advance the pump and have a better exhaust...mmmm

Most people would say that you're pretty much done and to swap a turbo diesel in there....not me.

You can probably fit GTD's bigger injectors and put a booster like NO2 or methanol....

So here are my suggestions: more fuel in (injectors) and a bottle or 2 (big Cummins use both to achieve 11's on the quarter mile).

Can anybody verify if the GTD injectors fit the 1.5 and 1.6? :arrow: :?:

Dr. Diesel · « **Reply #2 on:** October 02, 2004, 08:28:30 pm »

Give Giles a call at superior fuel injection 905-475-1122. His N/A diesel rabbit parts delivery car gained 22hp at the wheels just from installing one of his modded pumps. The 1.5L is only 4 hp less than the 1.6L and will respond nicely to a modded pump. Nitrous works good too, but you'd need a device to add fuel, either a TD pump, or some other mechanism.

gldgti · « **Reply #3 on:** October 04, 2004, 06:00:12 am »

thanks for the suggestions and the welcome...

advanced the pump a little today, and found the car was significantly better. more torque at least.

pics of my car at..

http://scramjetsite.8m.com

BlackTieTD · « **Reply #4 on:** October 04, 2004, 09:44:03 am »

hey i had the old 1.5.... took the 'easy' route to more power and swapped it out for the 1.6TD though.

your car looks nice... keep up the good work. the NA diesels can be fast in such a light chassis if you get everything just right.

gldgti · « **Reply #5 on:** October 05, 2004, 04:56:02 pm »

thanks, i try to keep her looking good.

I'm a little intrigued by the post about 22hp gain at wheels just from a modded injector pump? is that for real? (obviously not for a 1.5...)

My longer term aspirations for the car is to do a 1.9tdi swap, but thats about 3 years away (when i finish uni and actually have some money).

Back on the IDI stuff, how important is it to get lots of air? and if i was to heavily modify the airbox, and start cutting big holes in it for more air hoses and run them straight to the front grille where i get clean cold air, am i likely to get a decent power increase?

thanks

racer_x · « **Reply #6 on:** October 05, 2004, 06:54:41 pm »

I'm a little skeptical about that claim of 22whp gained on the injection pump. There's power to be had there, but I don't know if there's that much. Unless the thing was in really bad shape when it started, and some of the gain is from repairing serious problems.

As for flowing more air in, it helps a bit. I run a "cowl induction" setup. I cut the front of the airbox and glued in a 3" thin wall PVC pipe. Then I fitted a small flange with a 3" thin wall PVC pipe to the "rain gutter" below the windshield. I have a flexible 3" duct between that flange and the inlet pipe on the airbox.

It seemed to help a bit at high speeds. Accelerating from 55mph to 70mph goes quicker with the cowl induction setup than with the stock airbox snorkel. It might help a little at low speeds, but the effect is greater at higher (for a diesel) speeds.

Dr. Diesel · « **Reply #7 on:** October 06, 2004, 03:32:23 am »

22 whp as measured (and re-measured, and re-re-measured) by a Gtech. Don't forget, hp is a function of RPM. Stock diesel pumps start choking off fuel delivery around 2800 rpm. Among other improvements, Giles' pumps simply deliver full fuel at much high rpm. Simply stated, it's allowing the engine to make the power it's naturally capable of. Ask any of the dudes on here who went for a scoot in that car during the last GTG. It's not unbelievable!

Red Rabbit · « **Reply #8 on:** October 06, 2004, 08:55:46 am »

Can this modded injection pump be used on a TB or just N/A's?.....and how much does one of these units go for?

BlackTieTD · « **Reply #9 on:** October 06, 2004, 02:15:07 pm »

...even more gains to be made when applied to TD engines....

i can't wait until i get my rabbit tuned up (new clutch) so i can send my pump out to giles. :lol:

janb · « **Reply #10 on:** October 06, 2004, 08:48:53 pm »

I have a few 1.5's
They actually like to rev better than 1.6 (shorter stroke)

It will like a tad increase in fueling (clockwise on fuel load screw) upper right rear of pump (likely has crimped 'stop') only 1/8 turn at a time, as engine can 'run-away' (do while running)

next time you have intake manifold off, polish and match ports, better yet use A2 intake ('85 -92)

be sure you have double down pipe (standard on north america 1.5's)

Might try 'ram induction' you should have a nice 200mm square area next to radiator, trim out grill for increased flow

lots of air; and fuel enough to smoke black on full acceleration

I like my 1.5's, but they are tough on head gaskets (11mm) I give them 10% extra torque, seems to help.

gldgti · « **Reply #11 on:** October 07, 2004, 07:18:47 am »

fuel load screw....heard lots of posts about that one - i'll have to find it.

ive got the dual downpipe, no probs there.

interesting what you said about the head gaskets....do you mean they tend to take them out if you rev them too hard or all the time, or if you over rev them? (i mean, rev higher than the 5450rpm max that haynes tells not to...) also interesting about the extra torque.

it all seems to figure though - the 1.5 is a fairly revvy engine (for a diesel ;-) - all the power is above 3000rpm really - since its almost faster to accellerate from 100km/h to 110 than from 80-90 (4th gear)....

BlackTieTD · « **Reply #12 on:** October 07, 2004, 08:51:04 am »

Quote from: "gldgti"

interesting what you said about the head gaskets....do you mean they tend to take them out if you rev them too hard or all the time, or if you over rev them? (i mean, rev higher than the 5450rpm max that haynes tells not to...) also interesting about the extra torque.

thats what happened to the old 1.5 in my rabbit. head gasket blew apart inside the engine (no major external leak) and one morning i came out to a coolant resevoir filled with oil. i didn't over-rev... might have driven it hard but i was careful not to rev it high much. could have been the original head gasket though, who knows.